A randomized, controlled study in adults of the immunogenicity of a novel hepatitis B vaccine containing MF59 adjuvant.

The safety and immunogenicity of a novel hepatitis B virus (HBV) vaccine containing recombinant PreS2 and S antigens combined with MF59 adjuvant (HBV/MF59) was evaluated in healthy adults (N=230) who were randomized to receive 2 or 3 immunizations of either the study vaccine or a licensed control vaccine (Recombivax HB). After a single immunization, 105 of 118 (89%) recipients of HBV/MF59 achieved protective serum levels of anti-HBs antibody (> 10 mIU/ml), compared with 13 of 110 (12%) recipients of licensed vaccine (P < 0.001). The geometric mean titer (GMT) after 2 doses of HBV/MF59 given 2 months apart (13,422 mIU/ml) was more than 5-fold higher than that following 3 doses of licensed vaccine given over 6 months (2,346 mIU/ml; P < 0.001). The GMT following 3 injections of HBV/MF59 (249,917 mIU/ml) was 100-fold higher than licensed vaccine (P < 0.001). Anti-PreS2 antibodies were elicited in over 90% of the subset of HBV/MF59 recipients tested. Both vaccines were well tolerated; transient, mild-to-moderate local inflammation was the major postinjection reaction.     

Comparing the safety and immunogenicity of a candidate TB vaccine MVA85A administered by intramuscular and intradermal delivery

Background

New vaccines to prevent tuberculosis are urgently needed. MVA85A is a novel viral vector TB vaccine candidate designed to boost BCG-induced immunity when delivered intradermally. To date, intramuscular delivery has not been evaluated. Skin and muscle have distinct anatomical and immunological properties which could impact upon vaccine-mediated cellular immunity.

Methods

We conducted a randomised phase I trial comparing the safety and immunogenicity of 1 × 10⁸ pfu MVA85A delivered intramuscularly or intradermally to 24 healthy BCG-vaccinated adults.

Results

Intramuscular and intradermal MVA85A were well tolerated. Intradermally-vaccinated subjects experienced significantly more local adverse events than intramuscularly-vaccinated subjects, with no difference in systemic adverse events. Both routes generated strong and sustained Ag85A-specific IFNγ T cell responses and induced multifunctional CD4+ T cells. The frequencies of CD4+ T cells expressing chemokine receptors CCR4, CCR6, CCR7 and CXCR3 induced by vaccination was similar between routes.

Conclusions

In this phase I trial the intramuscular delivery of MVA85A was well tolerated and induced strong, durable cellular immune responses in healthy BCG vaccinated adults, comparable to intradermal delivery. These findings are important for TB vaccine development and are of relevance to HIV, malaria, influenza and other intracellular pathogens for which T cell-inducing MVA-based vaccine platforms are being evaluated.     

Induction of antigen-specific CD8+ T cells, T helper cells, and protective levels of antibody in humans by particle-mediated administration of a hepatitis B virus DNA vaccine

A DNA vaccine against the hepatitis B virus (HBV) was evaluated for safety and induction of immune responses in 12 healthy, hepatitis-na?ve human volunteers using the needle-free PowderJect system to deliver gold particles coated with DNA directly into cells of the skin. Three groups of four volunteers received three administrations of DNA encoding the surface antigen of HBV at one of the three dose levels (1, 2, or 4 microg). The vaccine was safe and well tolerated, causing only transient and mild to moderate responses at the site of administration. HBV-specific antibody and both CD4+ and CD8+ T cell responses were measured before and after each immunization. All the volunteers developed protective antibody responses of at least 10 mIU/ml. In volunteers who were positive for the HLA class I A2 allele, the vaccine also induced antigen-specific CD8+ T cells that bound HLA-A2/HBsAg(335-343) tetramers, secreted IFN-gamma, and lysed target cells presenting a hepatitis B surface antigen (HBsAg) CTL epitope. Enumeration of HBsAg-specific T cells producing cytokine indicated preferential induction of a Type 1 T helper cell response. These results provide the first demonstration of a DNA vaccine inducing protective antibody titers and both humoral and cell-mediated immune responses in humans.     

Comparison of the immunogenicity and safety of measles vaccine administered alone or with live, attenuated Japanese encephalitis SA 14-14-2 vaccine in Philippine infants

Japanese encephalitis (JE) virus is a major cause of disease, disability, and death in Asia. An effective, live, attenuated JE vaccine (LJEV) is available; however, its use in routine immunization schedules is hampered by lack of data on concomitant administration with measles vaccine (MV). This study evaluated the immunogenicity and reactogenicity of LJEV and MV when administered at the same or separate study visits in infants younger than 1 year of age. Three groups of healthy infants were randomized to receive LJEV at age of 8 months and MV at 9 months (Group 1; n=100); MV and LJEV together at 9 months (Group 2; n=236); or MV and LJEV at 9 and 10 months, respectively (Group 3; n=235). Blood was obtained 4 weeks after each vaccine administration to determine antibody levels for measles and JE. Reactogenicity was assessed by parental diaries and clinic visits. Four weeks after immunization, measles seroprotection rates (defined as > or =340 mIU/ml) were high and comparable in all three groups and specifically, rates in the combined MV-LJEV (Group 2) were not statistically inferior to those in Group 3 receiving MV separately (96% versus 100%, respectively). Likewise, the LJEV seroprotection rates were high and similar between the three groups. The reactogenicity profiles of the three vaccine schedules were also analogous. LJEV and MV administered together are well tolerated and immunogenic in infants younger than 1 year. These results should facilitate incorporation of LJEV into routine immunization schedules with MV.     

Immunogenicity and tolerability of a quadrivalent meningococcal glycoconjugate vaccine in children 2–10 years of age

Meningococcal disease incidence is highest in infants, but a significant burden of disease also occurs in children. In this Phase II, single-centre US study, 619 healthy children (2–10 years of age) received one dose of an investigational quadrivalent meningococcal CRM₁₉₇-conjugated vaccine (MenACWY-CRM) or a licensed quadrivalent meningococcal polysaccharide vaccine (MPSV4). Immunogenicity was assessed using the serum bactericidal assay with human complement (hSBA) at 1 and 12 months post-vaccination. Local and systemic reactions were recorded for 7 days, all adverse events (AEs) for 1 month, and medically significant and serious AEs (SAEs) for 12 months post-vaccination. For all four serogroups, more MenACWY-CRM recipients achieved an hSBA titre ≥1:4 at 1 month post-vaccination (A: 82%; C: 83%; W-135: 95%; Y: 91%) compared with the group that received MPSV4 (A: 45%; C: 66%; W-135: 71%; Y: 61%); this difference persisted through to 12 months post-vaccination. Both vaccines were well tolerated. In children 2–10 years of age, MenACWY-CRM induced a higher immune response than that of MPSV4, and was well tolerated.     

Safety and immunogenicity of attenuated dengue virus vaccines (Aventis Pasteur) in human volunteers

A randomized, controlled, double-blinded study was conducted to determine safety and immunogenicity of five live attenuated dengue vaccines produced by Aventis Pasteur (AvP). The study was completed with 40 flavivirus non-immune volunteers: five recipients of each monovalent (dengue-1, dengue-2, dengue-3, or dengue-4) vaccine, ten recipients of tetravalent (dengue-1, dengue-2, dengue-3, and dengue-4) vaccine, and ten recipients of vaccine vehicle alone. All vaccines were administered in a single subcutaneous dose (range, 3.6-4.4 log(10) plaque forming units). No serious adverse reactions occurred in volunteers followed for 6 months after vaccination. Five vaccine recipients developed fever (T > or = 38.0 degrees C), including four tetravalent vaccinees between days 8 and 10 after vaccination. Dengue-1, dengue-2, dengue-3, or dengue-4 vaccine recipients reported similar frequency of mild symptoms of headache, malaise, and eye pain. Tetravalent vaccinees noted more moderate symptoms with onset from study days 8-11 and developed maculopapular rashes distributed over trunk and extremities. Transient neutropenia (white blood cells < 4000/mm3) was noted after vaccination but not thrombocytopenia (platelets < 100,000/mm3). All dengue-3, dengue-4, and tetravalent vaccine recipients were viremic between days 7 and 12 but viremia was rarely detected in dengue-1 or dengue-2 vaccinees. All dengue-2, dengue-3, and dengue-4, and 60% of dengue-1 vaccine recipients developed neutralizing and/or immunoglobulin M antibodies. All tetravalent vaccine recipients were viremic with dengue-3 virus and developed neutralizing antibodies to dengue-3 virus. Seven volunteers also had multivalent antibody responses, yet the highest antibody titers were against dengue-3 virus. The AvP live attenuated dengue virus vaccines are safe and tolerable in humans. The live attenuated tetravalent dengue vaccine was most reactogenic, and preferential replication of dengue-3 virus may have affected its infectivity and immunogenicity.     

Safety and immunogenicity of a combined vaccine against hepatitis A and B in patients with autoimmune hepatitis

Patients with autoimmune hepatitis (AIH) are a group at risk of disease exacerbation or relapse of the underlying disease should they fall ill with infectious hepatitis A (HAV) or B (HBV). Therefore, it seems appropriate to protect this group of persons against HAV and HBV disease by vaccination. An open study evaluated the safety, reactogenicity and immunogenicity of a combined HAV and HBV vaccine in 10 patients with AIH (6 patients aged 1-15 years and four patients aged 16+ years). The vaccine was administered using a three-dose vaccination schedule (0, 1 and 6 months). The vaccine course was well tolerated, safe and did not aggravate the clinical course of the underlying disease. Patients responded with 100% seroconversion for antibody to the HAV vaccine component and geometric mean antibody concentration (GIVIC) comparable to healthy cohorts. Response to the HBV component antigen was comparable to previous reports of HBV vaccination in immune compromised individuals with lower GMC than observed in healthy populations. One month after the third vaccine dose (month 7), all six vaccinees in the 1-15 years age group developed protective levels of anti-HBs as compared to two of the four vaccinees in the 16+ years age group.     

Evaluation of trivalent, live, cold-adapted (CAIV-T) and inactivated (TIV) influenza vaccines in prevention of virus infection and illness following challenge of adults with wild-type influenza A (H1N1), A (H3N2), and B viruses

Trivalent, live, cold-adapted influenza vaccine (CAIV-T) is highly effective in the prevention of influenza in children, and a variety of monovalent and bivalent cold-adapted influenza vaccines have been efficacious in adults. In order to determine the efficacy of CAIV-T in healthy adults, we administered CAIV-T, trivalent inactivated influenza vaccine (TIV) or placebo to 103 adults in randomized double-blind fashion, and then challenged those subjects who had pre-screening serum hemagglutination-inhibition antibody titers of 1:8 or less with wild-type influenza viruses corresponding to the strains contained in the vaccine. CAIV-T was well tolerated. Upon challenge with wild-type influenza virus, laboratory documented influenza illness (respiratory symptoms with either isolation of wild-type influenza virus from nasal secretions or 4-fold and/or greater HAI antibody response to challenge) occurred in 14/31 (45%) placebo recipients, 4/32 (13%) TIV recipients, and 2/29 (7%) CAIV-T recipients. The estimated protective efficacy of CAIV-T was therefore 85% and of TIV was 71%. These results are consistent with those of previous studies using monovalent preparations of cold-adapted influenza vaccine in this model, and indicate that CAIV-T will be an effective means to prevent influenza illness in adults.     

Safety and immunogenicity of an oral,inactivated enterotoxigenic Escherichia coli plus cholera toxin B subunit vaccine in Bangladeshi children 18-36 months of age

A phase II safety and immunogenicity study of an oral-formalin inactivated enterotoxigenic Escherichia coli (ETEC) vaccine containing six colonization factors (CFA/I, CS1, CS2, CS3, CS4, CS5) and 1mg of recombinant cholera toxin B subunit (the CF-BS-ETEC vaccine) was carried out in an urban slum of Dhaka city in Bangladesh. The study was carried out in a double blinded, placebo controlled design in 158 children, 18-36 months of age. Children were given two doses of the CF-BS-ETEC vaccine or the placebo which consisted of E. coli K12. The vaccine was well tolerated.The immune response was studied in 60 children (30 each in the placebo and vaccine group). Significant vaccine specific IgA antibody-secreting cell (ASC) responses were seen 7 days after ingestion of the first and second dose of the vaccine. The responses to CFA/I (P相似文献   

Immune response to hepatitis B vaccine in HIV-infected subjects using granulocyte-macrophage colony-stimulating factor (GM-CSF) as a vaccine adjuvant: ACTG study 5220

HIV-infected persons are at risk for HBV co-infection which is associated with increased morbidity and mortality. Unfortunately, protective immunity following HBV vaccination in HIV-infected persons is poor. This randomized, phase II, open-label study aimed to evaluate efficacy and safety of 40 mcg HBV vaccine with or without 250 mcg GM-CSF administered at day 0, weeks 4 and 12. HIV-infected individuals ≥18 years of age, CD4 count ≥200 cells/mm³, seronegative for HBV and HCV, and naïve to HBV vaccination were eligible. Primary endpoints were quantitative HBsAb titers and adverse events. The study enrolled 48 subjects. Median age and baseline CD4 were 41 years and 446 cells/mm³, 37 were on ART, and 26 subjects had undetectable VL. Vaccination was well tolerated. Seven subjects in the GM-CSF arm reported transient grade ≥2 signs/symptoms (six grade 2, one grade 3), mostly aches and nausea. GM-CSF had no significant effect on VL or CD4. Four weeks after vaccination, 26 subjects (59%) developed a protective antibody response (HBsAb ≥10 mIU/mL; 52% in the GM-CSF arm and 65% in the control arm) without improved Ab titer in the GM-CSF vs. control arm (median 11 mIU/mL vs. 92 mIU/mL, respectively). Response was more frequent in those with CD4 ≥350 cells/mm³ (64%) than with CD4 <350 cells/mm³ (50%), though not statistically significant. GM-CSF as an adjuvant did not improve the Ab titer or the development of protective immunity to HBV vaccination in those receiving an accelerated vaccine schedule. Given the common routes of transmission for HIV and HBV, additional HBV vaccine research is warranted.     

Interaction between neonatal vitamin A supplementation and timing of measles vaccination: A retrospective analysis of three randomized trials from Guinea-Bissau

Background

In Guinea-Bissau we conducted three trials of neonatal vitamin A supplementation (NVAS) from 2002 to 2008. None of the trials found a beneficial effect on mortality. From 2003 to 2007, an early measles vaccine (MV) trial was ongoing, randomizing children 1:2 to early MV at 4.5 months or no early MV, in addition to the usual MV at 9 months. We have previously found interactions between vitamin A and vaccines.

Objective

We investigated whether there were interactions between NVAS and early MV.

Design

We compared the mortality of NVAS and placebo recipients: first, from 4.5 to 8 months for children randomized to early MV or no early MV; and second, from 9 to 17 months in children who had received two MV or one MV. Mortality rates (MR) were compared in Cox models producing mortality rate ratios (MRR).

Results

A total of 5141 children were randomized to NVAS (N = 3015) or placebo (N = 2126) and were later randomized to early MV (N = 1700) or no early MV (N = 3441). Between 4.5 and 8 months, NVAS compared with placebo was associated with higher mortality in early MV recipients (MR = 30 versus MR = 0, p = 0.01), but not in children who did not receive early MV (p for interaction between NVAS and early MV = 0.03). From 9 to 17 months NVAS was not associated with mortality. Overall, from 4.5 to 17 months NVAS was associated with increased mortality in early MV recipients (Mortality rate ratio = 5.39 (95% confidence interval: 1.62, 17.99)).

Conclusions

These observations indicate that NVAS may interact with vaccines given several months later. This may have implications for the planning of future child intervention programs.     

Indicators of therapeutic effect in FIT-06, a Phase II trial of a DNA vaccine, GTU(®)-Multi-HIVB, in untreated HIV-1 infected subjects

Background

Combination highly active antiretroviral therapy (HAART) has significantly decreased HIV-1 related morbidity and mortality globally transforming HIV into a controllable condition. HAART has a number of limitations though, including limited access in resource constrained countries, which have driven the search for simpler, affordable HIV-1 treatment modalities. Therapeutic HIV-1 vaccines aim to provide immunological support to slow disease progression and decrease transmission. We evaluated the safety, immunogenicity and clinical effect of a novel recombinant plasmid DNA therapeutic HIV-1 vaccine, GTU^®-multi-HIVB, containing 6 different genes derived from an HIV-1 subtype B isolate.

Methods

63 untreated, healthy, HIV-1 infected, adults between 18 and 40 years were enrolled in a single-blinded, placebo-controlled Phase II trial in South Africa. Subjects were HIV-1 subtype C infected, had never received antiretrovirals, with CD4 ≥ 350 cells/mm³ and pHIV-RNA ≥ 50 copies/mL at screening. Subjects were allocated to vaccine or placebo groups in a 2:1 ratio either administered intradermally (ID) (0.5 mg/dose) or intramuscularly (IM) (1 mg/dose) at 0, 4 and 12 weeks boosted at 76 and 80 weeks with 1 mg/dose (ID) and 2 mg/dose (IM), respectively. Safety was assessed by adverse event monitoring and immunogenicity by HIV-1-specific CD4+ and CD8+ T-cells using intracellular cytokine staining (ICS), pHIV-RNA and CD4 counts.

Results

Vaccine was safe and well tolerated with no vaccine related serious adverse events. Significant declines in log pHIV-RNA (p = 0.012) and increases in CD4+ T cell counts (p = 0.066) were observed in the vaccine group compared to placebo, more pronounced after IM administration and in some HLA haplotypes (B*5703) maintained for 17 months after the final immunisation.

Conclusions

The GTU^®-multi-HIVB plasmid recombinant DNA therapeutic HIV-1 vaccine is safe, well tolerated and favourably affects pHIV-RNA and CD4 counts in untreated HIV-1infected individuals after IM administration in subjects with HLA B*57, B*8101 and B*5801haplotypes.     

Comparison of the safety and immunogenicity of hepatitis B virus surface antigen co-administered with an immunostimulatory phosphorothioate oligonucleotide and a licensed hepatitis B vaccine in healthy young adults

BACKGROUND: Many individuals do not respond to a three-dose series of hepatitis B vaccine (HBV) and most do not achieve a protective antibody response until after dose 2 or 3. METHODS: Healthy, seronegative 18-28 year old adults were randomly assigned in equal numbers to receive two doses of the experimental vaccine (HBV-ISS without alum) (0, 8 weeks) and placebo (24 weeks) or Engerix-B (0, 8, 24 weeks). Adverse events were collected during the first week and at 4 weeks after each injection. Antibodies were measured 4 weeks after dose 1; before, 1 and 4 weeks after dose 2, and before, 1 and 4 weeks after dose 3 and at 1 year. RESULTS: Ninety-nine participants were enrolled (65% female; mean age 22.6 years). 79% of HBV-ISS and 12% of Engerix-B recipients had a protective antibody response 4 weeks post dose 1 (geometric mean concentration [GMC] 23.0 and 1.87 mIU/mL, respectively). By 1 week post dose 2, 100% of HBV-ISS and 18% Engerix-B recipients had protective levels (GMC 1603 versus 2.40 mIU/mL). Rates of adverse events were low and similar in both groups; headache and fatigue were the most common systemic adverse events in up to 1/3 of both groups. Mild injection-site tenderness was more common after HBV-ISS than Engerix-B after both doses (74-77% compared to 34-58%; p相似文献   

Randomized study of intradermal compared to intramuscular hepatitis B vaccination in HIV-infected children without severe immunosuppression

HIV infected individuals have poorer response to hepatitis B vaccine (HBV) compared to normal host. Intradermal administration (ID) facilitates the exposure of antigen to antigen-presenting cells compared to intramuscular administration (IM).HIV-infected children aged 1-18 years with CD4% ≥ 15% or 200 cells/mm³ who had negative HBs Ag, antiHBs, and antiHBc were randomized to receive 3-dose of HBV via ID (2 μg/dose) or IM (10 μg/dose) route at months 0, 2, and 6. AntiHBs titers were measured at months 2, 6 and 7 after first HBV. AntiHBs ≥ 10 mIU/mL was considered protective and AntiHBs > 100 mIU/mL was considered good response.Participants included 41 in ID and 39 in IM arms. 64% had completed 3-doses HBV during infancy. The mean (SD) of age, nadir CD4% and current CD4% were 12 (3.3) years, 10.6 (7.9)% and 28 (8.0)% respectively. 91% were on HAART and 84% had undetectable HIV-RNA.Proportion of children with protective antiHBs in ID vs. IM group were 19.5% vs. 25.6% at month 2, 56.1% vs. 76.9% at month 6, and 90.2% vs. 92.3% at month 7 (NS, all). The geometric mean (95% confidence interval) of antiHBs titer in ID vs. IM group were 112.5 (34.4-367.6) vs. 141.2 (49.4-404.1) mIU/mL at month 2 (p = 0.74), 70.4 (39.8-124.4) vs. 132.1 (79.4-219.8) mIU/mL at month 6 (p = 0.10), and 157.0 (103.0-239.3) vs. 458.9 (324.0-647.0) mIU/mL at month 7 (p < 0.001). However, only 56.1% of the ID arm had good response to HBV compared to 82.1% in the IM arm (p = 0.01). The predictors for being a good responder to HBV were IM administration [OR 4.0, 95%CI 1.4-11.8, p = 0.012] and body weight <35 kg at baseline [OR 3.8, 95%CI 1.3-10.8, p = 0.013]. No adverse events grade 3/4 occurred.In conclusion, HIV-infected children without severe immune suppression, both ID and IM routes of HBV resulted in similar rates of protective antibody titers. However, high antibody titers to HBV were more common with IM; therefore, IM administration is preferred.     

Safety and immunogenicity of respiratory syncytial virus purified fusion protein-2 vaccine in pregnant women

A randomized, double-blind, placebo controlled study was carried out to determine the safety and immunogenicity of RSV PFP-2 vaccine (Wyeth-Lederle Vaccines, NY) in 35 healthy women in the third trimester of pregnancy and their offspring. Infants were followed during their first RSV season for occurrence and severity of respiratory illnesses. RSV-PFP-2 vaccine was safe and well tolerated by pregnant women. Mild pain at the site of injection occurred in 65% of PFP-2 and 13% of placebo recipients (P=0.005). There were no systemic reactions, fever, or serious adverse events associated with vaccine administration in mothers. All 35 infants were born healthy, and there were no differences among the groups in perinatal or neonatal outcomes, growth and development in the first year of life. During the RSV season, there was no increase in the frequency or morbidity associated with respiratory tract illnesses in infants of vaccine recipients. 15/20 (75%) vaccine recipients had a response to PFP-2 by Western blot vs. 0/15 placebo recipients (P<0.01). 19/20 (95%) vaccine recipients had a > or =4 fold rise in IgG ELISA Ab after immunization with PFP-2 vs. 0/15 placebo recipients (P<0.01). Geometric mean concentrations of IgG ELISA Ab were 4 fold higher in infants of vaccine recipients at birth, 2 and 6 months after delivery than in infants of placebo recipients (P<0.01). A modest (0.5log2) increase in neutralization Ab was observed in vaccine recipients and their infants. The half-life of maternal antibodies in infants was > or =3 weeks. There was no evidence of enhanced T-cell or cytokine activity in infants of vaccine recipients vs. infants of placebo recipients. Vaccine specific anti-F IgA and IgG concentrations in breast milk were higher in mothers who received RSV-PFP-2.     

母牛分枝杆菌疫苗预防结核病的细胞免疫学和安全性研究

目的评价正常人群接种母牛分枝杆菌疫苗的安全性和细胞免疫学效果,探讨母牛分枝杆菌疫苗用于大龄儿童加强免疫,预防结核病的可行性。方法随机选择5~7岁的健康儿童,先进行结核菌素纯蛋白衍生物(TB-PPD)试验,然后分成TB-PPD试验阳性组和阴性组,每组分别接种母牛分枝杆菌疫苗3针,每针间隔2周。分别采集接种前和接种后1个月的血标本,用流式细胞仪检测各项细胞免疫学指标,观察两组免疫前后细胞免疫学指标的变化情况和接种后不良反应的发生率。结果观察300人次的接种,未发现任何不良反应。TB-PPD试验阴性组免疫前后淋巴细胞、Th细胞(CD4)、Ts细胞(CD8)、T细胞数均比免疫前显著增加,差异有显著的统计学意义。90%的TB-PPD试验阴性者细胞数的增长≥2个标准差,增长率92%~96%。TB-PPD试验阳性者免疫前后淋巴细胞数、Th细胞数均比接种疫苗前增加,差异有显著的统计学意义。TB-PPD试验阳性组免疫前后呈现出良好的双向免疫调节功能,淋巴细胞数、Th细胞数的增长率近70%,且增长幅度在1个标准差左右。结论对TB-PPD试验阴性或阳性者进行母牛分枝杆菌疫苗接种,均显示了较好的安全性和细胞免疫学效果,因此探讨用母牛分枝杆菌疫苗预防结核病,尤其是用于大龄儿童及青少年免疫预防有非常积极的意义。     

Broad and potent immune responses to a low dose intradermal HIV-1 DNA boosted with HIV-1 recombinant MVA among healthy adults in Tanzania

Background

We conducted a phase I/II randomized placebo-controlled trial with the aim of exploring whether priming with a low intradermal dose of a multiclade, multigene HIV-1 DNA vaccine could improve the immunogenicity of the same vaccine given intramuscularly prior to boosting with a heterologous HIV-1 MVA among healthy adults in Dar es Salaam, Tanzania.

Methods

Sixty HIV-uninfected volunteers were randomized to receive DNA plasmid vaccine 1 mg intradermally (id), n = 20, or 3.8 mg intramuscularly (im), n = 20, or placebo, n = 20, using a needle-free injection device. DNA plasmids encoding HIV-1 genes gp160 subtype A, B, C; rev B; p17/p24 gag A, B and Rtmut B were given at weeks 0, 4 and 12. Recombinant MVA (10⁸ pfu) expressing HIV-1 Env, Gag, Pol of CRF01_AE or placebo was administered im at month 9 and 21.

Results

The vaccines were well tolerated. Two weeks after the third HIV-DNA injection, 22/38 (58%) vaccinees had IFN-γ ELISpot responses to Gag. Two weeks after the first HIV-MVA boost all 35 (100%) vaccinees responded to Gag and 31 (89%) to Env. Two to four weeks after the second HIV-MVA boost, 28/29 (97%) vaccinees had IFN-γ ELISpot responses, 27 (93%) to Gag and 23 (79%) to Env. The id-primed recipients had significantly higher responses to Env than im recipients. Intracellular cytokine staining for Gag-specific IFN-γ/IL-2 production showed both CD8⁺ and CD4⁺ T cell responses. All vaccinees had HIV-specific lymphoproliferative responses. All vaccinees reacted in diagnostic HIV serological tests and 26/29 (90%) had antibodies against gp160 after the second HIV-MVA boost. Furthermore, while all of 29 vaccinee sera were negative for neutralizing antibodies against clade B, C and CRF01_AE pseudoviruses in the TZM-bl neutralization assay, in a PBMC assay, the response rate ranged from 31% to 83% positives, depending upon the clade B or CRF01_AE virus tested.

Conclusions

This vaccine approach is safe and highly immunogenic. Low dose, id HIV-DNA priming elicited higher and broader cell-mediated immune responses to Env after HIV-MVA boost compared to a higher HIV-DNA priming dose given im. Three HIV-DNA priming immunizations followed by two HIV-MVA boosts efficiently induced Env-antibody responses.     

Strain-specific Plasmodium falciparum multifunctional CD4+ T cell cytokine expression in Malian children immunized with the FMP2.1/AS02A vaccine candidate

Based on Plasmodium falciparum (Pf) apical membrane antigen 1 (AMA1) from strain 3D7, the malaria vaccine candidate FMP2.1/AS02_A showed strain-specific efficacy in a Phase 2 clinical trial in 400 Malian children randomized to 3 doses of the AMA1 vaccine candidate or control rabies vaccine on days 0, 30 and 60. A subset of 10 Pf(−) (i.e., no clinical malaria episodes) AMA1 recipients, 11 Pf(+) (clinical malaria episodes with parasites with 3D7 or Fab9-type AMA1 cluster 1 loop [c1L]) AMA1 recipients, and 10 controls were randomly chosen for analysis. Peripheral blood mononuclear cells (PBMCs) isolated on days 0, 90 and 150 were stimulated with full-length 3D7 AMA1 and c1L from strains 3D7 (c3D7) and Fab9 (cFab9). Production of IFN-γ, TNF-α, IL-2, and/or IL-17A was analyzed by flow cytometry. Among AMA1 recipients, 18/21 evaluable samples stimulated with AMA1 demonstrated increased IFN-γ, TNF-α, and IL-2 derived from CD4⁺ T cells by day 150 compared to 0/10 in the control group (p < 0.0001). Among AMA1 vaccines, CD4⁺ cells expressing both TNF-α and IL-2 were increased in Pf(−) children compared to Pf(+) children. When PBMCs were stimulated with c3D7 and cFab9 separately, 4/18 AMA1 recipients with an AMA1-specific CD4⁺ response had a significant response to one or both c1L. This suggests that recognition of the AMA1 antigen is not dependent upon c1L alone. In summary, AMA1-specific T cell responses were notably increased in children immunized with an AMA1-based vaccine candidate. The role of CD4⁺TNF-α⁺IL-2⁺-expressing T cells in vaccine-induced strain-specific protection against clinical malaria requires further exploration. Clinicaltrials.gov Identifier: NCT00460525.     

Humoral response to hepatitis B vaccination and its relationship with T CD45RA+ (naïve) and CD45RO+ (memory) subsets in HIV-1-infected subjects

HIV disease leads to defects in cell-mediated immunity, impairing the immune response to new and recall antigens. We studied 55 HIV 1-infected patients who received of recombinant DNA hepatitis B vaccine and 20 controls. The overall hepatitis B virus (HBV) seroconversion rate was 59%. The median CD4+ T cell count among responders was 452 cell/mm(3), higher than non-responders (359 cells/mm(3)). The HIV plasmaviral loads were higher in non-responders. We concluded that total T CD4 cell count, memory T CD4+ cells and lower plasma viral load among HIV-1-infected subjects treated with HAART could be used to predict the immune response to vaccination with hepatitis B vaccine. Thus, considering cost benefits, HVB vaccination should be preferentially provided to HIV-infected patients with T CD4 cells count over 450 cells/mm(3), preferentially whose under HIV replication controlled.     

Phase I trial of RV3-BB rotavirus vaccine: A human neonatal rotavirus vaccine

Introduction

RV3 is a human neonatal rotavirus strain (G3P[6]) that has been associated with asymptomatic neonatal infection and replicates well in the infant gut. RV3-BB rotavirus vaccine has been developed as a rotavirus vaccine candidate for administration at birth.

Methods

A single-centre, double-blind, randomised placebo-controlled Phase I study evaluated the safety and tolerability of a single oral dose of the second generation RV3-BB rotavirus vaccine (8.3 × 10⁶ FFU/mL) in 20 adults, 20 children and 20 infants (10 vaccine and 10 placebo per age cohort). Vaccine take was defined as seroconversion (a 3-fold increase in serum anti-rotavirus IgA or serum neutralising antibody (SNA) from baseline at day 28 post-dose) or evidence of RV3-BB viral replication in the faeces by RT-PCR analysis 3–6 days post-vaccination. RV3-BB presence was confirmed by sequence analysis.

Results

The RV3-BB vaccine was well tolerated in all participants, with no pattern of adverse events shown to be associated with the study vaccine. In the infant cohort, vaccine take was demonstrated in 8/9 infants following a single dose of vaccine compared with 2/7 placebo recipients. In the infant vaccine group, 5/9 infants exhibited either IgA or SNA seroconversion and 7/9 infants had evidence of RV3-BB replication on days 3–6, compared with 2/7 infants who seroconverted and 0/10 infants with evidence of replication in the placebo group. Two infants in the placebo group had serological evidence of a rotavirus infection within the 28-day study period: one demonstrated an IgA and the other an SNA response, with wild-type virus replication detected in another infant.

Conclusion

A single dose of RV3-BB rotavirus vaccine was well tolerated in adults, children and infants. Most infants (8/9) who received RV3-BB demonstrated vaccine take following a single dose. These data support progression of RV3-BB to Phase II immunogenicity and efficacy trials.