Correlates and characteristics of hepatitis C virus‐specific T‐cell immunity in exposed uninfected high‐risk prison inmates

Some hepatitis C (HCV)‐uninfected, high‐risk individuals have HCV‐specific cellular immunity without viraemia or seroconversion. The characteristics of these responses and the risk behavioural associations were studied in 94 subjects in a prospective cohort of recently seronegative prisoners reporting injecting drug use (IDU). Detailed behavioural data were collected. HCV antibody and PCR testing were performed. ELISpot assays for HCV‐induced interferon (IFN)‐γ and interleukin (IL)‐2 production by T lymphocytes, as well as multiplex in vitro cytokine production assays, were performed. Seventy‐eight subjects remained antibody and PCR negative and 16 seroconverted. Of the seronegative group, 22 (28%) had IFN‐γ ELISpot responses in comparison with 13 of the 16 seroconverters (82%). This seronegative immune status was associated positively with injecting anabolic steroids and negatively with a recent break from IDU. The IFN‐γ ELISpot responses involved both CD4 and CD8 T lymphocytes and were comparable in magnitude, but narrower in specificity, in uninfected subjects than in seroconverters. A subset of seronegative subjects had HCV‐induced cytokine production patterns comparable with the seroconverters with increased production of IFN‐γ, IL‐2 and tumour necrosis factor (TNF)‐α and reduced IL‐10 in response to nonstructural peptides. In conclusion, comparable patterns of HCV‐specific cellular immunity are found in recently infected subjects and in a minority of high‐risk, uninfected subjects. Further characterization of these responses and their protective efficacy will inform HCV vaccine development.     

Studies of cell‐mediated immune responses to influenza vaccination in systemic lupus erythematosus

Objective

Both antibody and cell‐mediated responses are involved in the defense against influenza. In patients with systemic lupus erythematosus (SLE), a decreased antibody response to subunit influenza vaccine has been demonstrated, but cell‐mediated responses have not yet been assessed. This study was therefore undertaken to assess cell‐mediated responses to influenza vaccination in patients with SLE.

Methods

Fifty‐four patients with SLE and 54 healthy control subjects received subunit influenza vaccine. Peripheral blood mononuclear cells and sera were obtained before and 1 month after vaccination. Cell‐mediated responses to A/H1N1 and A/H3N2 vaccines were evaluated using an interferon‐γ (IFNγ) enzyme‐linked immunospot assay and flow cytometry. Antibody responses were measured using a hemagglutination inhibition test.

Results

Prior to vaccination, patients with SLE had fewer IFNγ spot‐forming cells against A/H1N1 compared with control subjects and a lower frequency of IFNγ‐positive CD8+ T cells. After vaccination, the number of IFNγ spot‐forming cells increased in both patients and control subjects, although the number remained lower in patients. In addition, the frequencies of CD4+ T cells producing tumor necrosis factor and interleukin‐2 were lower in patients after vaccination compared with healthy control subjects. As expected for a subunit vaccine, vaccination did not induce a CD8+ T cell response. For A/H3N2‐specific responses, results were comparable. Diminished cell‐mediated responses to influenza vaccination were associated with the use of prednisone and/or azathioprine. The increase in A/H1N1‐specific and A/H3N2‐specific antibody titers after vaccination was lower in patients compared with control subjects.

Conclusion

In addition to a decreased antibody response, cell‐mediated responses to influenza vaccination are diminished in patients with SLE, which may reflect the effects of the concomitant use of immunosuppressive drugs. This may render these patients more susceptible to (complicated) influenza infections.

     

The mucosal and systemic immune responses elicited by a chitosan-adjuvanted intranasal influenza H5N1 vaccine

Please cite this paper as: Svindland et al. The mucosal and systemic immune responses elicited by a chitosan‐adjuvanted intranasal influenza H5N1 vaccine. Influenza and Other Respiratory Viruses DOI:10.1111/j.1750‐2659.2011.00271.x. Background Development of influenza vaccines that induce mucosal immunity has been highlighted by the World Health Organisation as a priority (Vaccine 2005;23:1529). Dose‐sparing strategies and an efficient mass‐vaccination regime will be paramount to reduce the morbidity and mortality of a future H5N1 pandemic. Objectives This study has investigated the immune response and the dose‐sparing potential of a chitosan‐adjuvanted intranasal H5N1 (RG‐14) subunit (SU) vaccine in a mouse model. Methods Groups of mice were intranasally immunised once or twice with a chitosan (5 mg/ml)‐adjuvanted SU vaccine [7·5, 15 or 30 μg haemagglutinin (HA)] or with a non‐adjuvanted SU vaccine (30 μg HA). For comparison, another group of mice were intranasally immunised with a whole H5N1 (RG‐14) virus (WV) vaccine (15 μg HA), and the control group consisted of unimmunised mice. Results The chitosan‐adjuvanted SU vaccine induced an immune response superior to that of the non‐adjuvanted SU vaccine. Compared with the non‐adjuvanted SU group, the chitosan‐adjuvanted SU vaccine elicited higher numbers of influenza‐specific antibody‐secreting cells (ASCs), higher concentrations of local and systemic antibodies and correspondingly an improved haemagglutination inhibition (HI) and single radial haemolysis (SRH) response against both the homologous vaccine strain and drifted H5 strains. We measured a mixed T‐helper 1/T‐helper 2 cytokine response in the chitosan‐adjuvanted SU groups, and these groups had an increased percentage of virus‐specific CD4⁺ T cells producing two Thelper 1 (Th1) cytokines simultaneously compared with the non‐adjuvanted SU group. Overall, the WV vaccine induced higher antibody concentrations in sera and an HI and SRH response similar to that of the chitosan‐adjuvanted SU vaccine. Furthermore, the WV vaccine formulation showed a stronger bias towards a T‐helper 1 profile than the SU vaccine and elicited the highest frequencies of CD4⁺ Th1 cells simultaneously secreting three different cytokines (INFγ⁺, IL2⁺ and INFα⁺). As expected, two immunisations gave a better immune response than one in all groups. The control group had very low or not detectable results in the performed immunoassays. Conclusion The cross‐clade serum reactivity, improved B‐ and T‐cell responses and dose‐sparing potential of chitosan show that a chitosan‐adjuvanted intranasal influenza vaccine is a promising candidate vaccine for further preclinical development.     

Innate immune responses against Cryptosporidium parvum infection

Cryptosporidium parvum infects intestinal epithelial cells and is commonly the parasite species involved in mammalian cryptosporidiosis, a major health problem for humans and neonatal livestock. In mice, immunologically mediated elimination of C. parvum requires CD4⁺ T cells and IFN‐γ. However, innate immune responses also have a significant protective role in both adult and neonatal mice. NK cells and IFN‐γ have been shown to be important components in immunity in T and B cell‐deficient mice, but IFN‐γ‐dependent resistance has also been demonstrated in alymphocytic mice. Epithelial cells may play a vital role in immunity as once infected these cells have increased expression of inflammatory chemokines and cytokines and demonstrate antimicrobial killing mechanisms, including production of NO and antimicrobial peptides. Toll‐like receptors facilitate the establishment of immunity in mice and are involved in the development of inflammatory responses of infected epithelial cells and also dendritic cells.     

Early IL‐10 predominant responses are associated with progression to chronic hepatitis C virus infection in injecting drug users

Summary. The critical events in clearance or persistence of hepatitis C virus (HCV) infection are unknown but likely to be determined early in acute infection. Type 1 and type 2 cytokine production was assessed by HCV peptide ELISpot and multiplex in vitro cytokine production assays in longitudinally collected samples from 20 untreated participants enrolled in the Australian Trial in Acute Hepatitis C (ATAHC); a prospective cohort of acute HCV infection (77% injecting drug users, IDU). Significantly higher interleukin‐10 (IL‐10) production (P = 0.048), in the relative absence of interferon‐gamma (IFN‐γ) and IL‐2 production, was present early in HCV infection in those who progressed to chronic infection. In contrast, viral clearance was associated with a greater magnitude and broader specificity of IFN‐γ (magnitude P < 0.001, breadth P = 0.004) and IL‐2 responses, in the relative absence of IL‐10. Early IL‐10 production was correlated with higher HCV RNA level at baseline (P = 0.046) and week 12 (P = 0.018), while IFN‐γ and IL‐2 production was inversely correlated with HCV RNA level at baseline (IFN‐γP = 0.020, IL‐2 P = 0.050) and week 48 (IFN‐γP = 0.045, IL‐2 P = 0.026). Intracellular staining (ICS) indicated the HCV‐specific IFN‐γ response was primarily from CD8⁺ T cells and NK cells, whereas IL‐10 production was predominantly from monocytes, with a subset of IL‐10 producing CD8⁺ T cells present only in those who progressed to chronic infection. IL‐10, an immunoregulatory cytokine, appears to play a key role in progression to chronic HCV infection.     

Type I IFNs promote the early IFN‐γ response and the IL‐10 response in Leishmania mexicana infection

The protozoan parasite Leishmania mexicana causes chronic cutaneous disease in humans and most mouse strains. We previously showed that STAT4‐deficient mice, but not IL‐12p40‐deficient mice, have more parasites and progressively growing lesions unlike those of wild‐type mice, the lesions and parasite burdens of which plateau by 10–12 weeks post‐infection. This demonstrates a STAT4‐dependent, IL‐12/IL‐23‐independent pathway of parasite control. Type I IFNs are important in viral and other infections and can activate STAT4. We found that IFN‐α/βR‐deficient mice have a nonpersistent, early IFN‐γ defect, and a persistent, early IL‐10 defect, without changes in serum IL‐12 or LN‐derived nitric oxide. We found less IL‐10 per cell in CD25⁺CD4⁺ T cells and possibly fewer IL‐10‐producing cells in the draining LN of IFN‐α/βR‐deficient vs. wild‐type mice. IFN‐α/βR‐deficient mice have chronic, nonprogressive disease, like wild‐type mice, suggesting that IL‐10 and IFN‐γ defects may balance each other. Our data indicate that although type I IFNs help promote early Th1 responses, they are not the missing activators of STAT4 responsible for partial control of L. mexicana. Also, the lack of lesion resolution in IFN‐α/βR‐deficient mice despite lower IL‐10 levels indicates that other pathways independent of T cell IL‐10 help prevent an IL‐12‐driven clearance of parasites.     

Cytokine response in pediatric patients with pandemic influenza H1N1 2009 virus infection and pneumonia: comparison with pediatric pneumonia without H1N1 2009 infection

Objectives

We investigated serum cytokine levels in pediatric patients with pandemic influenza H1N1 2009 virus (H1N1) infection‐pneumonia and in pediatric patients with pneumonia but without H1N1 infection, and examined correlations between cytokine levels and clinical/laboratory findings.

Methods

Fifty‐seven cases of infection by H1N1 were confirmed by RT‐PCR and enrolled. Of these 57 cases, 26 had a severe H1N1 infection (group 1), and 31 had a mild H1N1 infection (group 2). Sera from 18 cases with pneumonia without H1N1 infection (group 3) were used as controls. The serum levels of 10 cytokines were determined by multiplex assay.

Results

The serum levels of IFN‐α, IL‐6, and IP‐10 were significantly higher in H1N1 infected cases than in group 3, and levels of IL‐6 and IP‐10 were significantly higher in group 1 than in group 2. The level of IL‐10 was significantly higher in groups 1 and 3 than in group 2. However, levels of IFN‐γ and IL‐17 were not significantly different between the three groups. IL‐1β, IL‐4, and MIP‐1α were not detectable in most patients. IP‐10 and IL‐6 levels were found to show negative correlations with lymphocyte count and oxygen saturation.

Conclusions

We found higher levels of cytokines (IFN‐α, IL‐6, IP‐10) of innate immunity than those of acquired immunity in pediatric H1N1 infection. Of the cytokines found to be increased in cases with H1N1 infection, IP‐10 and IL‐6 were found to be correlated with disease severity (lymphopenia and hypoxia). IP‐10 and IL‐6 may be important markers in pediatric H1N1 infection. Pediatr Pulmonol. 2011; 46: 1233–1239. © 2011 Wiley Periodicals, Inc.

     

Pandemic influenza 1918 H1N1 and 1968 H3N2 DNA vaccines induce cross-reactive immunity in ferrets against infection with viruses drifted for decades

Please cite this paper as: Bragstad et al. (2010) Pandemic influenza 1918 H1N1 and 1968 H3N2 DNA vaccines induce cross‐reactive immunity in ferrets against infection with viruses drifted for decades. Influenza and Other Respiratory Viruses 5(1), 13–23. Background Alternative influenza vaccines and vaccine production forms are needed as the conventional protein vaccines do not induce broad cross‐reactivity against drifted strains. Furthermore, fast vaccine production is especially important in a pandemic situation, and broader vaccine reactivity would diminish the need for frequent change in the vaccine formulations. Objective In this study, we compared the ability of pandemic influenza DNA vaccines to induce immunity against distantly related strains within a subtype with the immunity induced by conventional trivalent protein vaccines against homologous virus challenge. Methods Ferrets were immunised by particle‐mediated epidermal delivery (gene gun) with DNA vaccines based on the haemagglutinin (HA) and neuraminidase (NA) and/or the matrix (M) and nucleoprotein genes of the 1918 H1N1 Spanish influenza pandemic virus or the 1968 H3N2 Hong Kong influenza pandemic virus. The animals were challenged with contemporary H1N1 or H3N2 viruses. Results We demonstrated that DNA vaccines encoding proteins of the original 1918 H1N1 pandemic virus induced protective cross‐reactive immune responses in ferrets against infection with a 1947 H1N1 virus and a recent 1999 H1N1 virus. Similarly, a DNA vaccine, based on the HA and NA of the 1968 H3N2 pandemic virus, induced cross‐reactive immune responses against a recent 2005 H3N2 virus challenge. Conclusions DNA vaccines based on pandemic or recent seasonal influenza genes induced cross‐reactive immunity against contemporary virus challenge as good as or superior to contemporary conventional trivalent protein vaccines. This suggests a unique ability of influenza DNA to induce cross‐protective immunity against both contemporary and long‐time drifted viruses.     

T cells increase with gastric mucosal interleukin (IL)-7, IL-1, and Helicobacter pylori urease specific immunoglobulin levels via CCR2 upregulation in Helicobacter pylori gastritis

Background and Aims: The purpose of this study was to investigate possible factors that could impact on γδ T cell accumulation in the gastric mucosa. Method: Subjects were 22 Helicobacter pylori (H. pylori)‐free and 75 H. pylori‐infected mucosa biopsies classified into grades I～III gastritis as per our previous study. The number of γδ‐ and 45 RO‐positive T cells were determined by immunostaining. Gastric mucosal anti‐H. pylori urease specific antibodies and interleukin (IL)‐1β, IL‐2, 4, 7, 10 and IL‐12 levels were assayed by enzyme‐linked immunosorbent assay (ELISA). CC chemokine receptor 2 (CCR2) expression levels, migration, and cytokine production in γδ T cells stimulated by H. pylori urease were also evaluated. Results: The γδ T cell count was significantly higher in grade III gastritis which exhibits strong immunoglobulin (Ig)A and IgG responses to H. pylori urease with lymphoid follicles than in other groups. γδ T cell count was significantly correlated with IL‐1β and interleukin‐7 (IL‐7) levels in the gastric mucosa. H. pylori urease immunoreactivity was detected in lamina propria of grade III gastritis, along with many γδ T cells. After H. pylori eradication therapy, the γδ T cell count in grade III gastritis significantly decreased. H. pylori urease stimulated significant increases in CCR2 expression levels, although to a lesser degree than those induced by IL‐7 stimulation in both peripheral and mucosal γδ T cells. Interferon (IFN)‐γ and IL‐10 production was also stimulated by H. pylori urease in peripheral γδ T cells. Conclusions: Gastric mucosal increases in IL‐7 and IL‐1β closely corresponded to the accumulation of γδ T cells in gastric mucosa. An association was also seen between γδ T cell accumulation and H. pylori urease‐specific Ig levels.     

Mechanisms of modulation of experimental autoimmune encephalomyelitis by chronic Trichinella spiralis infection in Dark Agouti rats

Trichinella spiralis is a helminth that provokes Th2 and anti‐inflammatory type responses in an infected host. Our previous studies using Dark Agouti (DA) rats indicated that T. spiralis infection reduced experimental autoimmune encephalomyelitis (EAE) severity in rats. The aim of this study was to analyse the mechanisms underlying EAE suppression driven by T. spiralis infection. Reduced clinical and histological manifestations of the disease were accompanied by increased IL‐4 and IL‐10 production and decreased IFN‐γ and IL‐17 production in draining lymph node cells. This indicates that T. spiralis infection successfully maintains a Th2 cytokine bias regardless of EAE induction. High IL‐10 signifies parasite‐induced anti‐inflammatory and/or regulatory cell responses. Transfer of splenic T cell‐enriched population of cells from T. spiralis‐infected rats into EAE immunized rats caused amelioration of EAE and in some cases protection from disease development. This population of cells contained higher proportion of CD4⁺ CD25⁺ Foxp3⁺ regulatory cells and produced high level of IL‐10 when compared with uninfected rats.     

The role of IL‐1β in reduced IL‐7 production by stromal and epithelial cells: a model for impaired T‐cell numbers in the gut during HIV‐1 infection

Abstract. Thang PH, Ruffin N, Brodin D, Rethi B, Cam PD, Hien NT, Lopalco L, Vivar N, Chiodi F (Karolinska Institutet, Stockholm, Sweden; National Institute of Hygiene and Epidemiology, Hanoi, Vietnam; San Raffaele Scientific Institute, Milan, Italy). The role of IL‐1β in reduced IL‐7 production by stromal and epithelial cells: a model for impaired T‐cell numbers in the gut during HIV‐1 infection. J Intern Med 2010; 268 : 181–193. Objectives. Interleukin (IL)‐7 is a key cytokine in T‐cell homeostasis. Stromal cells, intestinal epithelial cells and keratinocytes are known to produce this cytokine. The mechanisms and cellular factors regulating IL‐7 production are still unclear. We assessed whether IL‐1β and interferon (IFN)‐γ, cytokines produced during inflammatory conditions, may impact on IL‐7 production. Design. We used human intestinal epithelial cells (DLD‐1 cell line) and bone marrow stromal cells (HS27 cell line), known to produce IL‐7; IL‐7 production was evaluated at the mRNA and protein levels. To assess whether treatment of HS27 cells with IL‐1β and/or IFN‐γ leads to changes in the gene expression of cytokines, Toll‐like receptors (TLRs) and chemokines, we analysed gene expression profiles using the whole‐genome microarray Human Gene 1.0 ST. Results. We found that IFN‐γ enhanced the expression of IL‐7 mRNA (P < 0.001) in both cell lines. IL‐1β treatment led to a significant down‐regulation (P < 0.001) of IL‐7 mRNA expression in both cell lines. The IL‐7 concentration in supernatants collected from treated DLD‐1 and HS27 cell cultures reflected the trend of IL‐7 mRNA levels. The gene profiles revealed dramatic changes in expression of cytokines and their receptors (IL‐7/IL‐7Rα; IL‐1α,IL‐1β/IL‐1R1; IFN‐γ/IFN‐γR1), of IFN regulatory factors (IRF‐1 and 2), of TLRs and of important chemo‐attractants for T cells. The microarray results were verified by additional methods. Conclusions. Our results are discussed in the setting of inflammation and T‐cell survival in the gut compartment during HIV‐1 infection where stromal and epithelial cells may produce factors that contribute to impaired IL‐7 homeostasis and homing of T cells.     

Decreased IFNγ production correlates with diminished production of cytokines by dendritic cells in patients infected with hepatitis C virus and receiving therapy

Summary. Toll‐like receptor (TLR) expression and the signalling pathways that lead to the production of accessory cytokines by antigen‐presenting cells (APCs) both have potential to limit T‐cell responses to viral antigens. Here, expression of TLR and retinoic acid inducible gene I (RIG‐I) and responses evoked through these proteins were evaluated in patients chronically infected with HCV, before and during pegylated interferon‐α (IFNα) and ribavirin therapy. Expression of TLR2, 3, 4, 7, 9 and RIG‐I on APCs and cytokine production by DCs were measured by flow cytometry. Production of IL‐12 by myeloid dendritic cells (mDCs), IFNα by plasmacytoid cells (pDCs) and IFNγ by peripheral blood mononuclear cells was measured after stimulation with TLR ligands. IFNγ ELISpot responses to HCV and CMV antigens declined on therapy. TLR and RIG‐I expression on mDCs, pDCs, B cells and monocytes was either similar or higher in patients than that in controls and generally increased during therapy. Therapy impaired IL‐12 and IFNα production by DCs and reduced production of IFNγ by PBMCs after stimulation with ligands for TLR3, TLR7/8, TLR9 and RIG‐I. This was independent of whether patients attained a sustained virological response. HCV disease and interferon‐based therapy reduced IFN‐γ responses to HCV antigens and TLR agonists. This was not accompanied by reduced expression of pertinent TLR but correlated with diminished production of co‐stimulatory cytokines by DCs stimulated via TLR.     

Functional T‐lymphocyte dichotomy in the peripheral blood of patients with unstable angina

OBJECTIVES. Herein, we investigated the percentage of T‐helper (Th1) and Th2 cells among the general T‐cell population in the peripheral blood of patients with stable angina (SA) and unstable angina (UA). BACKGROUND. Recent evidence suggests that Th1 cells and the cytokines that they secrete (especially IFN‐γ) have a role in the activation of macrophages, promotion of clot formation and destabilization of atherosclerotic plaques. Thus, Th1 cytokines may contribute to the initiation and progression of UA. In contrast, cytokines secreted by Th2 cells (e.g. IL‐10) are known to inhibit activation and proliferation of Th1 cells and the secretion of IFN‐γ, lysosomal enzymes and metalloproteinases. Therefore, we sought to examine whether the ratio of IFN‐γ to IL‐10 secreting cells is altered in patients with UA. METHODS. The percentage of Th1 and Th2 cells among the general T‐cell population was determined by fluorescent intracellular cytokine staining (IFN‐γ and IL‐10, out of the total CD3 positive cells). RESULTS. The percentage of T‐cells positive for intracellular IFN‐γ was significantly higher in patients with UA (n = 22) in comparison with SA (n = 20) patients (39.0±2.8% and 29.6±2.7%, respectively. P = 0.02). There was no significant difference in intracellular IL‐10 positive cells between the two groups. In addition, there was no significant difference in the ratio between the intracellular IFN‐γ positive cells and the intracellular IL‐10 positive cells. CONCLUSIONS. There is an increased activity of Th1 cells in patients with UA in comparison with patients with SA. There is no evidence of heightened activity of Th2 cells in either group. Thus, IFN‐γ secreted by peripheral blood T‐lymphocytes,may be an important immunomodulator contributing to destabilization of the atheromatous plaque lying at the base of the etiopathogenesis of unstable angina.     

Pandemic and seasonal influenza viruses among patients with acute respiratory illness in Kashmir (India)

Please cite this paper as: Koul PA., et al. (2011) Pandemic and seasonal influenza viruses among patients with acute respiratory illness in Kashmir (India). Influenza and Other Respiratory Viruses 5(6), e521–e527. Background With the emergence of pandemic influenza A (2009A/H1N1) virus in India, we sought to determine the prevalence and clinical presentations of seasonal and pandemic influenza viruses among acute respiratory illness (ARI) patients from Srinagar, a temperate climate area in northern India, during the peak winter season. Methods Combined throat and nasal swabs, obtained from 194 (108 male) presenting with ARI from January to March 2010 (Week 53‐week 10), were tested by RT‐PCR for influenza A and B, including 2009A/H1N1 viruses. HA1 gene of selected 2009A/H1N1‐positive samples was sequenced, and phylogenetic analysis was carried out. Results Twenty‐one (10·8%, age 15–80 years, median age 40 years) patients tested positive for influenza viruses: 13 (62%) for 2009A/H1N1 virus, 6 (28·5%) for seasonal influenza A (H3N2), and 2 (9·5%) for influenza B. Twelve of the 13 patients with 2009A/H1N1 presented with febrile ARI, and eight had associated comorbidities. All of the patients recovered. Phylogenetic analysis of HA gene (n = 8) revealed that all strains from Srinagar clustered in 2009A/H1N1 clade seven along with the other 2009A/H1N1 strains from India. Amino acid substitutions in the HA protein defining clade seven (P83S, S203T, and I321V) were found in almost all isolates from Srinagar. Conclusions Both seasonal and 2009A/H1N1 viruses appear to be associated with ARI in Srinagar. The 2009A/H1N1 in Srinagar is genetically similar to globally circulating clade 7 strains, with unique signature sequences in the HA gene. Further investigations into ascertain the role of these mutations in possible alteration of the virulence and transmissibility of the virus are needed.     

Prophylactic properties of a Leishmania‐specific hypothetical protein in a murine model of visceral leishmaniasis

In this work, the effect of vaccination of a newly described Leishmania infantum antigenic protein has been studied in BALB/c mice infected with this parasite species. The LiHyD protein was characterized after a proteomic screening performed with the sera from dogs suffering visceral leishmaniasis (VL). Its recombinant version was expressed, purified and administered to BALB/c mice in combination with saponin. As a result of vaccination and 10 weeks after challenge using an infective dose of L. infantum stationary promastigotes, vaccinated mice showed lower parasite burdens in different organs (liver, spleen, bone marrow and footpads’ draining lymph nodes) than mice inoculated with the adjuvant alone or the vaccine diluent. Protected mice showed anti‐Leishmania IgG2a antibodies and a predominant IL‐12‐driven IFN‐γ production (mainly produced by CD4⁺ T cells) against parasite proteins, whereas unprotected controls showed anti‐Leishmania IgG1 antibodies and parasite‐mediated IL‐4 and IL‐10 responses. Vaccinated mice showed an anti‐LiHyD IgG2a humoral response, and their spleen cells were able to secrete LiHyD‐specific IFN‐γ, IL‐12 and GM‐CSF cytokines before and after infection. The protection was correlated with the Leishmania‐specific production on nitric oxide. Altogether, the results indicate that the new LiHyD protein could be considered in vaccine formulations against VL.     

A consensus-hemagglutinin-based DNA vaccine that protects mice against divergent H5N1 influenza viruses

H5N1 influenza viruses have spread extensively among wild birds and domestic poultry. Cross-species transmission of these viruses to humans has been documented in over 380 cases, with a mortality rate of ≈60%. There is great concern that a H5N1 virus would acquire the ability to spread efficiently between humans, thereby becoming a pandemic threat. An H5N1 influenza vaccine must, therefore, be an integral part of any pandemic preparedness plan. However, traditional methods of making influenza vaccines have yet to produce a candidate that could induce potently neutralizing antibodies against divergent strains of H5N1 influenza viruses. To address this need, we generated a consensus H5N1 hemagglutinin (HA) sequence based on data available in early 2006. This sequence was then optimized for protein expression before being inserted into a DNA plasmid (pCHA5). Immunizing mice with pCHA5, delivered intramuscularly via electroporation, elicited antibodies that neutralized a panel of virions that have been pseudotyped with the HA from various H5N1 viruses (clades 1, 2.1, 2.2, 2.3.2, and 2.3.4). Moreover, immunization with pCHA5 in mice conferred complete (clades 1 and 2.2) or significant (clade 2.1) protection from H5N1 virus challenges. We conclude that this vaccine, based on a consensus HA, could induce broad protection against divergent H5N1 influenza viruses and thus warrants further study.     

The impact of alcohol on BCG-induced immunity against Mycobacterium tuberculosis

Background: Alcoholics are at heightened risk for developing active tuberculosis. This study evaluates chronic alcohol consumption in a murine model of vaccination with Mycobacterium bovis Bacille Calmette–Guèrin (BCG) and subsequent pulmonary infection with virulent Mycobacterium tuberculosis. Methods: BALB/c mice were administered the Lieber–DeCarli liquid ethanol diet or pair‐fed the liquid control diet for 3 weeks either before or after subcutaneous vaccination with M. bovis BCG. At least 3 weeks after BCG vaccination, groups of mice on the aforesaid diets were challenged with intratracheal infection with M. tuberculosis H37Rv. Lung mycobacterial burden, and lung and lung‐associated lymph node CD4⁺ lymphocyte production of tuberculosis‐specific interferon (IFN)‐γ were assayed. Popliteal lymph node lymphocytes from both dietary regimens undergoing BCG vaccination (in the absence of M. tuberculosis infection) were also evaluated for purified protein derivative–induced IFN‐γ production by ELISpot assay. Results: Mice begun on alcohol prior to vaccination with M. bovis BCG demonstrated impaired control of pulmonary challenge with virulent M. tuberculosis, as well as impaired lung CD4⁺ and popliteal lymph node T‐cell IFN‐γ responses. If BCG vaccination was delivered prior to initiation of alcohol feeding, the mice remained protected against a subsequent challenge with M. tuberculosis, and BCG‐induced immunity was not impaired in either the lung or the popliteal lymph nodes. Conclusions: Alcohol consumption blunts the development of the adaptive immune response to M. bovis BCG vaccination, which impairs the control of a secondary challenge with M. tuberculosis, but only if the alcohol exposure is begun prior to BCG vaccination. These results provide insight into mechanisms by which alcohol consumption impairs antimycobacterial immunity, including in response to vaccination and subsequent pathogenic challenge.     

Matrix-M adjuvanted virosomal H5N1 vaccine confers protection against lethal viral challenge in a murine model

Please cite this paper as: Pedersen et al. (2011) Matrix‐M adjuvanted virosomal H5N1 vaccine confers protection against lethal viral challenge in a murine model. Influenza and Other Respiratory Viruses 5(6), 426–437. Background A candidate pandemic influenza H5N1 vaccine should provide rapid and long‐lasting immunity against antigenically drifted viruses. As H5N1 viruses are poorly immunogenic, this may require a combination of immune potentiating strategies. An attractive approach is combining the intrinsic immunogenicity of virosomes with another promising adjuvant to further boost the immune response. As regulatory authorities have not yet approved a surrogate correlate of protection for H5N1 vaccines, it is important to test the protective efficacy of candidate H5N1 vaccines in a viral challenge study. Objectives This study investigated in a murine model the protective efficacy of Matrix‐M adjuvanted virosomal influenza H5N1 vaccine against highly pathogenic lethal viral challenge. Methods Mice were vaccinated intranasally (IN) or intramuscularly (IM) with 7·5 μg and 30 μg HA of inactivated A/Vietnam/1194/2004 (H5N1) (NIBRG‐14) virosomal adjuvanted vaccine formulated with or without 10 μg of Matrix‐M adjuvant and challenged IN with the highly pathogenic A/Vietnam/1194/2004 (H5N1) virus. Results and conclusions IM vaccination provided protection irrespective of dose and the presence of Matrix‐M adjuvant, whilst the IN vaccine required adjuvant to protect against the challenge. The Matrix‐M adjuvanted vaccine induced a strong and cross‐reactive serum antibody response indicative of seroprotection after both IM and IN administration. In addition, the IM vaccine induced the highest frequencies of influenza specific CD4+ and CD8+ T‐cells. The results confirm a high potential of Matrix‐M adjuvanted virosomal vaccines and support the progress of this vaccine into a phase 1 clinical trial.