Polyfunctional CD4 T-cells correlate with in vitro mycobacterial growth inhibition following Mycobacterium bovis BCG-vaccination of infants

BackgroundVaccination with Bacillus Calmette Guerin (BCG) protects infants against childhood tuberculosis however the immune mechanisms involved are not well understood. Further elucidation of the infant immune response to BCG will aid with the identification of immune correlates of protection against tuberculosis and with the design of new improved vaccines. The purpose of this study was to investigate BCG-induced CD4+ T-cell responses in blood samples from infants for cytokine secretion profiles thought to be important for protection against tuberculosis and compare these to PBMC-mediated in vitro mycobacterial growth inhibition.MethodsBlood from BCG-vaccinated or unvaccinated infants was stimulated overnight with Mycobacterium tuberculosis (M. tb) purified protein derivative (PPD) or controls and intracellular cytokine staining and flow cytometry used to measure CD4+ T-cell responses. PBMC cryopreserved at the time of sample collection were thawed and incubated with live BCG for four days following which inhibition of BCG growth was determined.ResultsPPD-specific IFNγ+TNFα+IL-2+CD4+ T-cells represented the dominant T-cell response at 4 months and 1 year after infant BCG. These responses were undetectable in age-matched unvaccinated infants. IL-17+ CD4+ T-cells were significantly more frequent in vaccinated infants at 4 months but not at 1-year post-BCG. PBMC-mediated inhibition of mycobacterial growth was significantly enhanced at 4 months post-BCG as compared to unvaccinated controls. In an analysis of all samples with both datasets available, mycobacterial growth inhibition correlated significantly with the frequency of polyfunctional (IFNγ+TNFα+IL-2+) CD4+ T-cells.ConclusionsThese data suggest that BCG vaccination of infants induces specific polyfunctional T-helper-1 and T-helper-17 responses and the ability, in the PBMC compartment, to inhibit the growth of mycobacteria in vitro. We also demonstrate that polyfunctional T-helper-1 cells may play a role in growth inhibition as evidenced by a significant correlation between the two.     

Varicella vaccination elicits a humoral and cellular response in children with rheumatic diseases using immune suppressive treatment

ObjectiveTo assess humoral and cellular responses to live-attenuated varicella zoster virus (VZV) vaccination of patients with juvenile idiopathic arthritis (JIA), juvenile dermatomyositis (JDM) or juvenile scleroderma (JScle) compared to those of healthy controls (HC).MethodsBefore, 4–6 weeks and one year after VZV vaccination, blood samples of patients and HC were collected. VZV-specific antibody concentrations were measured by ELISA and multiplex immune-assay. IFN-γ ELISpot assays were performed to assess VZV-specific T-cell responses. Cytokine production upon VZV stimulation were measured with a Luminex-assay.Results49 patients (39 JIA, 5 JDM, 5 JScle) and 18 HC were included. All patients used methotrexate (MTX), 16 also used corticosteroids, 3 patients used biologics. No disease flares were reported after vaccination. Antibody response to the vaccine was similar in patients and controls (p = 0.139). Use of immunosuppressive drugs did not affect the response (p = 0.203). A second vaccination (n = 21) increased VZV-specific antibody concentrations (p = 0.02). VZV-specific T-cells increased after vaccination (p = 0.043), with a cytokine profile suggesting a VZV-specific Th1 and cytotoxic T-cell response.ConclusionThe humoral response to VZV vaccination in patients with pediatric rheumatic diseases (PRD) is similar to that of HC. Generally, patients are able to mount a VZV-specific cellular response.This study has been registered in the Brazilian Clinical Trials Registry under number U1111-1189-9837.     

Characteristics of immune memory 10–15 years after primary hepatitis B vaccination

Background and aimsThe definition of immune memory after hepatitis B vaccination is still under debate. Therefore, we analysed hepatitis B surface antigen (HBsAg)-specific memory in more detail by investigating the kinetics of humoral and cellular responses after hepatitis B booster vaccination.MethodsThe anti-HBs kinetics of 23 individuals with anti-HBs titres below 10 IU/l, who had been vaccinated 10–15 years ago, was monitored at day 0, 3, 7, 14 and 28 after booster vaccination. HBsAg-specific IFNγ- and IL5-secreting cells in enriched CD4⁺ fraction were measured at day 0, 7 and 28 post-booster by enzyme-linked immunospot assay (ELISpot).Results22 of 23 subjects showed similar anti-HBs kinetic curves, including 3 of 4 subjects who did not reach anti-HBs titres of 10 IU/l. The steep anti-HBs increase started between day 3 and 7 and peaked around day 14. A plateau or only minimal changes were visible between day 14 and 28. 17.4% of subjects showed pre-booster cellular responses, and this rate had increased to 47.8% and 56.5% after 7 and 28 days, respectively. The kinetic patterns of T cell responses differed considerably among subjects. A dominance of Th2 responses (IL5 secretion) over Th1 responses (IFNγ secretion) could be observed.ConclusionsThe presence of B cell memory could be shown by a typical anamnestic anti-HBs response curve after a booster dose in all but one individual. In contrast, T cell responses to booster vaccination, which occurred in approximately 50% of participants, were rather heterogeneous.     

Humoral,T-cell and B-cell immune responses to seasonal influenza vaccine in solid organ transplant recipients receiving anti-T cell therapies

BackgroundWe analyzed the impact of the anti-T-cell agents basiliximab and antithymocyte globulins (ATG) on antibody and cell-mediated immune responses after influenza vaccination in solid-organ transplant recipients.Methods71 kidney and heart transplant recipients (basiliximab [n = 43] and ATG [n = 28]) received the trivalent influenza vaccine. Antibody responses were measured at baseline and 6 weeks post-vaccination by hemagglutination inhibition assay; T-cell responses were measured by IFN-γ ELISpot assays and intracellular cytokine staining (ICS); and influenza-specific memory B-cell (MBC) responses were evaluated using ELISpot.ResultsMedian time of vaccination from transplantation was 29 months (IQR 8–73). Post-vaccination seroconversion rates were 26.8% for H1N1, 34.1% for H3N2 and 4.9% for influenza B in the basiliximab group and 35.7% for H1N1, 42.9% for H3N2 and 14.3% for influenza B in the ATG group (p = 0.44, p = 0.61, and p = 0.21, respectively). The number of influenza-specific IFN-γ-producing cells increased significantly after vaccination (from 35 to 67.5 SFC/10⁶ PBMC, p = 0.0007), but no differences between treatment groups were observed (p = 0.88). Median number of IgG-MBC did not increase after vaccination (H1N1, p = 0.94; H3N2 p = 0.34; B, p = 0.79), irrespective of the type of anti-T-cell therapy.ConclusionsAfter influenza vaccination, a significant increase in antibody and T-cell immune responses but not in MBC responses was observed in transplant recipients. Immune responses were not significantly different between groups that received basiliximab or ATG.     

Effects of prior influenza virus vaccination on maternal antibody responses: Implications for achieving protection in the newborns

BackgroundIn the US, influenza vaccination is recommended annually to everyone ≥6 months. Prior receipt of influenza vaccine can dampen antibody responses to subsequent vaccination. This may have implications for pregnant women and their newborns, groups at high risk for complications from influenza infection.ObjectiveThis study examined effects of prior vaccination on maternal and cord blood antibody levels in a cohort of pregnant women in the US.Study designInfluenza antibody titers were measured in 141 pregnant women via the hemagglutination inhibition (HAI) assay prior to receipt of quadrivalent influenza vaccine, 30 days post-vaccination, and at delivery (maternal and cord blood). Logistic regression analyses adjusting for age, BMI, parity, gestational age at vaccination, and year of vaccination compared HAI titers, seroprotection, and seroconversion in women with versus without vaccination in the prior year.ResultsCompared to those without vaccination in the previous year (n = 50), women with prior vaccination (n = 91) exhibited higher baseline antibody titers and/or seroprotection rates against all four strains after controlling for covariates. Prior vaccination also predicted lower antibody responses and seroconversion rates at one month post-vaccination. However, at delivery, there were no significant differences in antibody titers or seroprotection rates in women or newborns, and no meaningful differences in the efficiency of antibody transfer, as indicated by the ratio of cord blood to maternal antibody titers at the time of delivery.ConclusionIn this cohort of pregnant women, receipt of influenza vaccine the previous year predicted higher baseline antibody titers and decreased antibody responses at one month post-vaccination against all influenza strains. However, prior maternal vaccination did not significantly affect either maternal antibody levels at delivery or antibody levels transferred to the neonate. This study is registered with the NIH as a clinical trial (NCT02148874).     

Greater activation of peripheral T follicular helper cells following high dose influenza vaccine in older adults forecasts seroconversion

BackgroundInfluenza related morbidity and mortality disproportionately impacts older adults. The serologic response to vaccine is diminished in older adults; however, high dose inactivated influenza vaccine (HD IIV) has shown improved rates of seroconversion compared to standard dose (SD IIV). We hypothesize this may be due to the superior ability of high dose vaccine to activate T follicular helper (Tfh) cells and provide B cell dependent T cell help.MethodsWe measured peripheral Tfh (pTfh) activation in 50 community dwelling adults 65 years or older who were randomly assigned to receive either the HD IIV or SD IIV.ResultsThe HD vaccination elicited significantly higher levels of ICOS expression on pTfh cells, at day 7 compared to SD vaccination (p = 0.02). The magnitude of the increase in ICOS+ pTfh cells from baseline to day 7 was predictive of seroconversion for both influenza A and B vaccination.ConclusionStrong Tfh activation in response to influenza vaccination forecasts successful seroconversion in older adults, and HD IIV elicits greater Tfh activation than SD IIV. Future vaccine studies should focus on ways to further optimize the Tfh response.     

Vitamin D levels and influenza vaccine immunogenicity among HIV-infected and HIV-uninfected adults

BackgroundVaccination is the most important preventive strategy against influenza, however post-vaccination antibody responses are often inadequate especially among HIV-infected persons. Vitamin D deficiency has been suggested to adversely influence immune responses and is highly prevalent among HIV-infected adults. Therefore, we evaluated the association between 25-hydroxyvitamin D [25(OH)D] levels and post-influenza vaccination responses.MethodsWe conducted a prospective cohort study evaluating the immunogenicity of monovalent influenza A (H1N1) vaccination among both HIV-infected and HIV-uninfected adults (18–50 years of age) during the 2009–2010 influenza season. Antibody titers were evaluated at baseline, day 28, and 6 months post-vaccination using hemagluttination inhibition assays. Serum 25(OH)D levels were measured at day 28. Univariate and multivariate regression analyses examined the association between 25(OH)D levels [categorized as <20 ng/ml (deficiency) vs. ⩾20 ng/ml] with the primary outcome of seroconversion. Secondary outcomes included seroprotection; a ⩾4-fold increase in titers; and geometric mean titers post-vaccination. Analyses were repeated using 25(OH)D levels as a continuous variable.ResultsA total of 128 adults [64 HIV-infected (median CD4 count 580 cells/mm³) and 64 HIV-uninfected] were included. Seroconversion at day 28 post-vaccination was achieved in fewer HIV-infected participants compared with HIV-uninfected participants (56% vs. 74%, p = 0.03). Vitamin D deficiency was more prevalent among HIV-infected persons vs. HIV-uninfected persons (25% vs. 17%), although not significantly different (p = 0.39). There were no associations found between lower 25(OH)D levels and poorer antibody responses at day 28 or 6 months for any of the study outcomes among either HIV-infected or HIV-uninfected adults.ConclusionVitamin D deficiency was common among both HIV-infected and HIV-uninfected adults, but lower levels did not predict antibody responses after H1N1 (2009) influenza vaccination. Low 25(OH)D levels do not explain poorer post-vaccination responses among HIV-infected persons.     

Key differences in B cell activation patterns and immune correlates among treated HIV-infected patients versus healthy controls following influenza vaccination

BackgroundThere is increasing recognition of the role of B cell dysfunction in HIV pathogenesis, but little is known about how these perturbations may influence responses to vaccinations.MethodsHealthy controls (n = 16) and antiretroviral therapy (ART)-treated aviremic HIV-infected subjects (n = 26) receiving standard-of-care annual influenza vaccinations were enrolled in the present study. Total bacterial 16 S rDNA levels were assessed by quantitative polymerase chain reactions in plasma. Serologic responses were characterized by ELISA, hemagglutination inhibition assay (HI), and microneutralization, and cell-mediated responses were assessed by ELISPOT (antigen-specific IgG+ antibody-secreting cells (ASCs)) and flow cytometry at pre-vaccination (D0), day 7–10 (D7) and day 14–21 (D14) post-vaccination.ResultsDecreased peripheral CD4+ T cell absolute counts and increased frequencies of cycling and apoptotic B cells were found at baseline in HIV-infected subjects relative to healthy controls. In healthy controls, post-vaccination neutralizing activities were related to the frequencies of vaccine-mediated apoptosis and cycling of B cells, but not to CD4+ T cell counts. In patients, both baseline and post-vaccination neutralizing activities were directly correlated with plasma level of bacterial 16S rDNA. However, overall vaccine responses including antibody titers and fold changes were comparable or greater in HIV-infected subjects relative to healthy controls.ConclusionB cell function correlates with measures of recall humoral immunity in response to seasonal influenza vaccination in healthy controls but not in ART-treated patients.     

Morning vaccination enhances antibody response over afternoon vaccination: A cluster-randomised trial

ObjectivesOlder adults are less able to produce a protective antibody response to vaccinations. One factor that contributes to this is immune ageing. Here we examined whether diurnal variations in immune responses might extend to the antibody response to vaccination.DesignWe utilised a cluster-randomised trial design.Setting24 General Practices (GPs) across the West Midlands, UK who were assigned to morning (9–11 am; 15 surgeries) or afternoon (3–5 pm; 9 surgeries) vaccination times for the annual UK influenza vaccination programme.Participants276 adults (aged 65+ years and without a current infection or immune disorder or taking immunosuppressant medication).InterventionsParticipants were vaccinated in the morning or afternoon between 2011 and 2013.Main outcome measuresThe primary outcome was the change in antibody titres to the three vaccine influenza strains from pre-vaccination to one month post-vaccination. Secondary outcomes of serum cytokines and steroid hormone concentrations were analysed at baseline to identify relationships with antibody responses.ResultsThe increase in antibody levels due to vaccination differed between morning and afternoon administration; mean difference (95% CI) for H1N1 A-strain, 293.3 (30.97–555.66) p = .03, B-strain, 15.89 (3.42–28.36) p = .01, but not H3N2 A-strain, 47.0 (−52.43 to 146.46) p = .35; those vaccinated in the morning had a greater antibody response. Cytokines and steroid hormones were not related to antibody responses. No adverse events were reported.ConclusionsThis simple manipulation in the timing of vaccine administration to favour morning vaccination may be beneficial for the influenza antibody response in older adults, with potential implications for vaccination strategies generally.Trial registrationThis trial is registered with the ISRCTN (ISRCTN70898162).     

Baseline serum interleukin-6 to interleukin-2 ratio is associated with the response to seasonal trivalent influenza vaccine in solid organ transplant recipients

BackgroundThe analysis of pre- and post-vaccination B-cell-associated cytokines might be useful in predicting the immunogenicity of seasonal trivalent influenza vaccine (TIV) in solid organ transplant (SOT) recipients.MethodsWe performed a subanalysis of a clinical trial that compared the safety and efficacy of high-dose intradermal (ID) versus intramuscular (IM) TIV in SOT recipients. Serum levels of selected cytokines (interferon [IFN]-γ, interleukin [IL]-2, IL-4, IL-5, IL-6, IL-12 and IL-21, and tumor necrosis factor [TNF]-α) were measured pre- and one month post-vaccination in 155 patients (with 84 and 71 receiving the ID and IM vaccines, respectively). Cytokine profiles were compared according to vaccine response (seroconversion [≥4-fold increase in hemagglutination inhibition antibody titers] to ≥1 influenza vaccine antigen).ResultsMean baseline IL-6 levels were higher (1.20 versus 0.65 pg/mL; P-value = 0.021) and IL-2 levels were lower (0.01 versus 0.50 pg/mL; P-value = 0.051) in patients achieving vaccine response. After adjusting for clinical variables, baseline IL-6/IL-2 ratio remained predictive of vaccine response (odds ratio per 10-unit increment: 1.06; 95% confidence interval: 1.02–1.10; P-value = 0.002). Vaccination induced an increase in TNF-α (P-value <0.0001) and a decrease in IL-5 levels (P-value = 0.0007). There were no significant differences in cytokine kinetics between vaccine responders and non-responders. Mean baseline TNF-α levels were higher in patients experiencing moderate-to-severe adverse events after vaccination (1.93 versus 1.72 pg/mL; P-value = 0.009).ConclusionsBaseline serum IL-6 and IL-2 levels, two cytokines that modulate the role of CD4⁺ T follicular helper cells and the terminal differentiation of B-cells, predict vaccine response in SOT recipients.     

Rubella specific cell-mediated and humoral immunity following vaccination in college students with low antibody titers

ObjectiveThis study measured cell-mediated immunity (CMI) and antibodies to clarify the basis of rubella reinfection after vaccination.MethodsIn a pool of 65 college students, 39 who exhibited hemagglutination–inhibition (HI) antibody titers against rubella of ≤1:16 were vaccinated with a rubella vaccine. The CMI was assessed with interferon-gamma release assay.ResultsThere was low correlation (r = 0.24) between the antibody titers and interferon-gamma levels at pre-vaccination status. Preexisting interferon-gamma levels were low in some subjects with low HI antibody titers of 1:8 and 1:16. Fifty-seven percent (4/7) of the subjects who were antibody-negative with past history of rubella vaccination at entry onto the study exhibited CMI. And 57% (4/7) of the subjects remained antibody-negative following a second vaccination, despite exhibiting CMI. HI antibody titers increased significantly after vaccination, whereas post-vaccination interferon-gamma levels did not exhibit significant increases. When subjects were divided (based on their past history of vaccination and antibody values) into natural infection and vaccination groups, HI antibody titers (mean ± SD) increased to 1:2^4.4 ± 1.4 from 1: 2^3.2 ± 0.4 (p = 0.065) in the natural infection group and to 1:2^4.4 ± 1.0 from 1:2^3.0 ± 0.8 (p < 0.00001) in the vaccination group following vaccination. The same classification revealed that interferon-gamma values did not increase significantly in either group following vaccination, but the interferon-gamma values at pre- and post-vaccination in the natural infection group were significantly higher than those at pre- and post-vaccination in the vaccination group (p < 0.05 and p < 0.05, respectively).ConclusionPre-vaccination interferon-gamma levels in each HI antibody titer group were similar. And there were some subjects with antibody-positive exhibited CMI-negative. These data may explain why rubella reinfection can occur in vaccinated seropositive individuals.     

Delayed BCG vaccination results in minimal alterations in T cell immunogenicity of acellular pertussis and tetanus immunizations in HIV-exposed infants

BackgroundBacille Calmette–Guerin (BCG) is effective in preventing disseminated tuberculosis (TB) in children but may also have non-specific benefits, and is thought to improve immunity to unrelated antigens through trained innate immunity. In HIV-infected infants, there is a risk of BCG-associated adverse events. We aimed to explore whether delaying BCG vaccination by 8 weeks, in utero or perinatal HIV infection is excluded, affected T-cell responses to B. pertussis (BP) and tetanus toxoid (TT), in HIV-exposed, uninfected infants.MethodsInfants were randomized to receive BCG vaccination at birth or 8 weeks of age. At 8 and 14 weeks, T cell proliferation and intracellular cytokine (IL-2, IL-13, IL-17, and IFN-γ) expression was analyzed in response to BP, TT and Staphylococcal enterotoxin B (SEB) antigens.ResultsDelaying BCG vaccination did not alter T-cell proliferation to BP or TT antigens. Infants immunized with BCG at birth had higher CD4+ T cell proliferation to SEB at 14 weeks of age (p = 0.018). Birth-vaccinated infants had increased CD8+ IL-2 expression in response to BP, but not TT or SEB, at 8 weeks. Infants vaccinated with BCG at 8 weeks had significantly lower IL-13 expression by BP-specific CD4+ and CD8+ T cells at 14 weeks (p = 0.032 and p = 0.0035, respectively). There were no observed differences in multifunctional cytokine response to TT, BP or SEB between infants vaccinated with BCG at birth versus 8 weeks of age.ConclusionDelaying BCG vaccination until 8 weeks of age results in robust T-cellular responses to BP and TT in HIV-exposed infants.Clinical Trial Registry: NCT02062580.     

Safety and immunogenicity of the novel H4:IC31 tuberculosis vaccine candidate in BCG-vaccinated adults: Two phase I dose escalation trials

BackgroundNovel vaccine strategies are required to provide protective immunity in tuberculosis (TB) and prevent development of active disease. We investigated the safety and immunogenicity of a novel TB vaccine candidate, H4:IC31 (AERAS-404) that is composed of a fusion protein of M. tuberculosis antigens Ag85B and TB10.4 combined with an IC31® adjuvant.MethodsBCG-vaccinated healthy subjects were immunized with various antigen (5, 15, 50, 150 μg) and adjuvant (0, 100, 500 nmol) doses of the H4:IC31 vaccine (n = 106) or placebo (n = 18) in two randomized, double-blind, placebo-controlled phase I studies conducted in a low TB endemic setting in Sweden and Finland. The subjects were followed for adverse events and CD4⁺ T cell responses.ResultsH4:IC31 vaccination was well tolerated with a safety profile consisting of mostly mild to moderate self-limited injection site pain, myalgia, arthralgia, fever and post-vaccination inflammatory reaction at the screening tuberculin skin test injection site. The H4:IC31 vaccine elicited antigen-specific CD4⁺ T cell proliferation and cytokine production that persisted 18 weeks after the last vaccination. CD4⁺ T cell expansion, IFN-γ production and multifunctional CD4⁺ Th1 responses were most prominent after two doses of H4:IC31 containing 5, 15, or 50 μg of H4 in combination with the 500 nmol IC31 adjuvant dose.ConclusionsThe novel TB vaccine candidate, H4:IC31, demonstrated an acceptable safety profile and was immunogenic, capable of triggering multifunctional CD4⁺ T cell responses in previously BCG-vaccinated healthy individuals. These dose-escalation trials provided evidence that the optimal antigen-adjuvant dose combinations are 5, 15, or 50 μg of H4 and 500 nmol of IC31.Trial registration: ClinicalTrials.gov, NCT02066428 and NCT02074956.     

Combined tetanus-diphtheria and pertussis vaccine during pregnancy: transfer of maternal pertussis antibodies to the newborn

Background and objectivesPertussis is currently an emerging public health concern in some countries with high vaccination coverage. It is expected that maternal pertussis immunization could provide newborn protection. We compared pertussis toxin antibody (anti-PT) levels in women during pregnancy (pre- and post-vaccination) with respect to levels in the newborn at delivery in women vaccinated during pregnancy. We also estimated anti-PT titers at primary infant vaccination.MethodsObservational study of pregnant women vaccinated with Tdap (≥20 weeks gestation) and their newborns between May 2012 and August 2013. Anti-PT levels were determined by ELISA in maternal (pre- and post-vaccination) and newborn blood.ResultsPre-vaccination, post-vaccination maternal and newborn samples were available in 132 subjects. Mean maternal age was 34.2 (SD 4.3) years. Median weeks of gestation at vaccination were 27.2 (Q1–Q3 21.7–30.8). Anti-PT (≥10 IU/ml) levels were found in 37.1% of maternal pre-vaccination samples (geometric mean titer (GMT) 7.9 IU/ml (95% CI 6.8–9.2)), 90.2% of post-vaccination samples (GMT 31.1 IU/ml (95% CI 26.6–36.3)) and 94.7% of newborns (GMT 37.8 IU/ml (95% CI 32.3–44.1)). The Lin concordance index between post-vaccination maternal and newborn samples was 0.8 (95% CI 0.8–0.9). Transplacental transfer ratio was 146.6%. At two months of age, 66% of newborns had estimated anti-PT levels ≥10 IU/ml.ConclusionsThere was a high correlation between anti-PT levels in mothers and newborns, with higher levels in newborns, which should be sufficient to provide protection against pertussis during the first months of life. Vaccination of pregnant women seems to be an immunogenic strategy to protect newborns until primary infant immunization.     

Lot-to-lot consistency,safety and immunogenicity of 3 lots of Haemophilus influenzae type b conjugate vaccine: results from a phase III randomized,multicenter study in infants

BackgroundVaccination against Haemophilus influenzae type b (Hib) is included in routine pediatric immunization schedule in the United States. Previous vaccine shortages have created the need for additional options for Hib vaccination.MethodsThis phase III, randomized, multi-centered study (NCT01000974) evaluated the safety and immunogenicity of a monovalent tetanus toxoid-conjugate Hib vaccine (Hib-TT) compared to a monovalent (Hib-TT control) and a combination Hib-TT vaccine. We hierarchically assessed lot-to-lot consistency of 3 Hib-TT lots and non-inferiority of Hib-TT to Hib-TT control. We co-administered routine pediatric vaccines with Hib-TT vaccines at 2, 4, 6 months (primary vaccination) and 15–18 months of age (booster vaccination). We recorded adverse events (AEs) for 4 (solicited) and 31 days (unsolicited) post-vaccination and serious AEs (SAEs) throughout the study.ResultsOf 4009 enrolled children, 3086 completed booster phase. Lot-to-lot consistency was not demonstrated. The study met statistical criteria for non-inferiority of Hib-TT to Hib-TT control in terms of immune responses to Hib and co-administered vaccines’ antigens, but not in terms of participants achieving post-primary vaccination anti-PRP levels ≥1 µg/mL. Because of the hierarchical nature of the objectives, non-inferiority could not be established. In all groups, 92.5–96.7% and 99.6–100% of participants achieved anti-PRP levels ≥0.15 µg/mL, while 78.3–89.8% and 97.9–99.1% had anti-PRP levels ≥1 µg/mL, post-primary and post-booster vaccination, respectively. Immune responses to co-administered vaccines and reported incidence of AEs were comparable among groups. We recorded SAEs for 107/2963 (3.6%), 24/520 (4.6%), and 21/520 (4.0%) children post-primary vaccination, and 29/2337 (1.2%), 4/435 (0.9%), and 2/400 (0.5%) children post-booster vaccination with Hib-TT, Hib-TT control and combination Hib-TT vaccine, respectively; 6/5330 (0.1%) SAEs in the Hib-TT groups were considered vaccine-related.ConclusionHib-TT induced seroprotective antibody concentrations in the majority of participants and was well-tolerated when co-administered with routine pediatric vaccines according to a 3 + 1 schedule.     

A randomized clinical trial in adults and newborns in South Africa to compare the safety and immunogenicity of bacille Calmette-Guérin (BCG) vaccine administration via a disposable-syringe jet injector to conventional technique with needle and syringe

IntroductionIntradermal bacille Calmette-Guérin (BCG) vaccination by needle-free, disposable-syringe jet injectors (DSJI) is an alternative to the Mantoux method using needle and syringe (NS). We compared the safety and immunogenicity of BCG administration via the DSJI and NS techniques in adults and newborn infants at the South African Tuberculosis Vaccine Initiative (SATVI) research site in South Africa.MethodThirty adults and 66 newborn infants were randomized 1:1 to receive intradermal BCG vaccine (0.1 mL in adults; 0.05 mL in infants) via DSJI or NS. Wheal diameter (mm) and skin fluid deposition at the site of injection (SOI) were measured immediately post-vaccination. Adverse events and SOI reactogenicity data were collected 30 min and 1, 2, 4, and 12 weeks after vaccination for adults and at 30 min and 4, 10, and 14 weeks for infants. Blood was collected in infants at 10 and 14 weeks to assess BCG-specific T-cell immune responses.ResultsMore infant BCG vaccinations by DSJI deposited >5 μL fluid on the skin surface, compared to NS (49% versus 9%, p = 0.001). However, all 12 infant vaccinations that did not produce any SOI wheal occurred in the NS group (36%, p < 0.001). Median wheal diameter, in participants for which an SOI wheal formed, did not differ significantly between groups in infants (combined 3.0 mm IQR 2.0 to 4.0, p = 0.59) or in adults (combined 9.0 mm IQR 7.0 to 10.0, p = 0.13). Adverse events were similar between study arms. Proportion of participants with BCG scars after three months did not differ in adults (combined 97%, p = 0.67) or infants (combined 62%, p = 0.13). Frequencies of BCG-specific clusters of differentiation 4 (CD4) and clusters of differentiation 8 (CD8) T-cells co-expressing IFN-γ, TNF-α, IL-2, and/or IL-17 were not different in the DSJI and NS groups.ConclusionBCG vaccination of newborn infants via DSJI was more likely to deliver an appropriate intradermal wheal at the SOI as compared to NS, despite leaving more fluid on the surface of the skin. Safety, reactogenicity, and antigen-specific T-cell immune responses did not differ between DSJI and NS techniques.     

Immunogenicity and safety of concomitant MF59-adjuvanted influenza vaccine and 23-valent pneumococcal polysaccharide vaccine administration in older adults

BackgroundConcomitant administration of influenza and pneumococcal vaccines facilitates their uptake by older adults; however, data on immunogenicity and safety of concomitant administration of adjuvanted trivalent inactivated influenza vaccine (aIIV3) and 23-valent pneumococcal polysaccharide vaccine (PPSV23) have not been reported.MethodsSubjects aged ≥65 years (N = 224) were randomized 1:1:1:1 to receive MF59-aIIV3 alone, MF59-aIIV3 + PPSV23 in contralateral arms, MF59-aIIV3 + PPSV23 in the same arm or PPSV23 alone (Clinical Trial Number – NCT02225327). Hemagglutination inhibition assay and multiplex opsonophagocytic killing assay were used to compare immunogenicity after single or concomitant vaccination.ResultsAll groups met immunogenicity criteria for the influenza vaccine in older adults with similar seroconversion rates and geometric mean fold-increases, irrespective of concomitant vaccinations and injection site. For each pneumococcal serotype, opsonic index (OI) increased markedly after the PPSV23 vaccination, irrespective of the concomitant influenza vaccine. All subjects showed an OI ≥ 8 for serotypes 6B, 18C and 19A post-vaccination, with a suggestion that the ipsilateral concomitant vaccination might be associated with higher OIs for some antigens. Local and systemic adverse events were more common in subjects receiving PPSV23 compared to those receiving aIIV3 alone.ConclusionsNo interference was observed with antibody responses to influenza or pneumococcal antigens when aIIV3 and PPSV23 were administered concomitantly.     

Hemagglutinin-specific CD4+ T-cell responses following 2009-pH1N1 inactivated split-vaccine inoculation in humans

Influenza A virus remains a major threat to public health, and the inactivated split-virus vaccine is the most prevalent vaccine used worldwide. However, our knowledge about cellular immune responses to the inactivated influenza virus vaccine and its correlation with humoral responses are yet limited, which has restricted our understanding of the vaccine’s protective mechanisms. Herein, in two clinical trials, T-cell responses specific for both previously identified human leucocyte antigen (HLA)-I-restricted epitopes from influenza virus and hemagglutinin (HA) protein were longitudinally investigated before, during, and after a two-dose vaccination with the inactivated 2009 pandemic H1N1 (2009-pH1N1) vaccine. A robust antibody response in all of the donors after vaccination was observed. Though no CD8⁺ T-cell responses to known epitopes were detected, HA-specific T-cell responses were primed following vaccination, and the responses were found to be mainly CD4⁺ T-cell dependent. However, HA-specific T-cells circulating in peripheral blood dropped to baseline levels 6 weeks after vaccination, but humoral immune responses maintained a high level for 4 months post-vaccination. Significant correlations between the magnitude of the HA-specific T-cell responses and hemagglutination inhibition antibody titers were demonstrated, indicating a priming role of HA-specific T-cells for humoral immune responses.In conclusion, our study indicates that HA-specific CD4⁺ T-cell responses can be primed by the inactivated 2009-pH1N1 vaccine, which may coordinate with the elicitation of antibody protection. These findings would benefit a better understanding of the immune protective mechanisms of the widely used inactivated 2009-pH1N1 vaccine.     

Methotrexate reduces vaccine-specific immunoglobulin levels but not numbers of circulating antibody-producing B cells in rheumatoid arthritis after vaccination with a conjugate pneumococcal vaccine

BackgroundTreatment with methotrexate (MTX) in patients with rheumatoid arthritis (RA) leads to decreased total immunoglobulin (Ig) levels and impairs vaccine-specific IgG antibody levels following pneumococcal vaccination. The mechanisms by which MTX exerts these effects in RA are unknown. We aimed to evaluate whether MTX reduces vaccine-specific serum Ig levels and their functionality in RA patients following vaccination with pneumococcal conjugate vaccine, and if numbers of antigen-specific circulating plasmablasts are affected.MethodsTen patients with RA on MTX and 10 RA patients without disease modifying anti-rheumatic drug (DMARD) were immunized with a dose 13-valent pneumococcal conjugate vaccine (Prevenar13). Circulating plasmablasts producing total IgG and IgA as well as specific IgG and IgA against two pneumococcal capsular serotypes (6B and 23F) were enumerated using ELISPOT 6 days after vaccination. IgG levels against both these serotypes were determined with ELISA before and 4–6 weeks after vaccination. Positive antibody response was defined as ⩾2-fold increase of pre-vaccination antibody levels. The functionality of vaccine specific antibodies to serotype 23F was evaluated by measuring their ability to opsonize bacteria using opsonophagocytic assay (OPA) in 4 randomly chosen RA patients on MTX and 4 RA patients without DMARD.ResultsAfter vaccination, RA patients on MTX showed significant increase in pre- to postvaccination antibody levels for 6B (p < 0.05), while patients without DMARD had significant increases for both 6B and 23F (p < 0.05 and p < 0.01, respectively). Only 10% of RA on MTX and 40% of RA patients without DMARD showed positive post-vaccination antibody responses for both serotypes. Increased opsonizing ability after vaccination was detected in 1 of 4 RA patients on MTX and 3 of 4 patients on RA without DMARD. However, numbers of circulating total and vaccine-specific IgG- or IgA-producing plasmablasts did not differ between RA patients with or without MTX.ConclusionsMTX treatment in RA leads to reduced vaccine-specific antibody responses and their functionality compared to untreated RA following pneumococcal vaccination using polysaccharide-protein conjugate vaccine. However, since there was no reduction in numbers of circulating total or vaccine-specific antibody-producing plasmablasts after vaccination this effect is probably not due to reduced activation of B cells in lymphoid tissue.Clinical trial registration: NCT02240888.