Activity of adjuvanted vaccines is difficult to predict in vitro and in vivo. The wide compositional and conformational range of formulated adjuvants, from aluminum salts to oil-in-water emulsions, makes comparisons between physicochemical and immunological properties difficult. Even within a formulated adjuvant class, excipient selection and concentration can alter potency and physicochemical properties of the mixture.
View Article and Find Full Text PDFThe formulation of TLR ligands and other immunomodulators has a critical effect on their vaccine adjuvant activity. In this work, the synthetic TLR4 ligand GLA was formulated with three distinct vaccine delivery system platforms (aqueous suspension, liposome, or oil-in-water emulsion). The effect of the different formulations on the adaptive immune response to protein subunit vaccines was evaluated in the context of a recombinant malaria antigen, Plasmodium berghei circumsporozoite protein (PbCSP).
View Article and Find Full Text PDFConsiderable effort has been directed to develop Mycobacterium tuberculosis vaccines to boost bacille Calmette-Guérin or for those who cannot be immunized with bacille Calmette-Guérin. We hypothesized that CD4(+) and CD8(+) T cell responses with a heterologous prime/boost vaccine approach could induce long-lived vaccine efficacy against M. tuberculosis in C57BL/6 mice.
View Article and Find Full Text PDFIt is generally assumed that the MHC class I antigen (Ag)-processing (CAP) machinery - which supplies peptides for presentation by class I molecules - plays no role in class II-restricted presentation of cytoplasmic Ags. In striking contrast to this assumption, we previously reported that proteasome inhibition, TAP deficiency or ERAAP deficiency led to dramatically altered T helper (Th)-cell responses to allograft (HY) and microbial (Listeria monocytogenes) Ags. Herein, we tested whether altered Ag processing and presentation, altered CD4(+) T-cell repertoire, or both underlay the above finding.
View Article and Find Full Text PDFSuccessful vaccine development against HIV will likely require the induction of strong, long-lasting humoral and cellular immune responses in both the systemic and mucosal compartments. Based on the known immunological linkage between the upper-respiratory and urogenital tracts, we explored the potential of nasal adjuvants to boost immunization for the induction of vaginal and systemic immune responses to gp140. Mice were immunized intranasally with HIV gp140 together with micellar and emulsion formulations of a synthetic TLR4 agonist, Glucopyranosyl Lipid Adjuvant (GLA) and responses were compared to R848, a TLR7/8 agonist, or chitosan, a non TLR adjuvant.
View Article and Find Full Text PDFThe natural TLR4 agonist lipopolysaccharide (LPS) has notable adjuvant activity. However, it is not useful as a vaccine adjuvant due to its toxicity. Glucopyranosyl lipid A (GLA) is a synthetic derivative of the lipid A tail of LPS with limited cytotoxicity, but strong potential to induce immune responses in mice, guinea pigs, non-human primates, and humans.
View Article and Find Full Text PDFDiagnosis of tuberculosis often relies on the ex vivo IFN-γ release assays QuantiFERON-TB Gold In-Tube and T-SPOT.TB. However, understanding of the immunological mechanisms underlying their diagnostic use is still incomplete.
View Article and Find Full Text PDFOne goal of vaccination is to promote development of mucosal effector cells that can immediately respond to peripheral infection. This is especially important for protection against viruses that enter the host through the respiratory tract. We show that targeting the OX40 costimulatory receptor (CD134) strongly promotes mucosal memory in the CD8 T cell compartment.
View Article and Find Full Text PDFInnate immune responses to vaccine adjuvants based on lipopolysaccharide (LPS), a component of gram-negative bacterial cell walls, are driven by Toll-like receptor (TLR) 4 and adaptor proteins including MyD88 and TRIF, leading to the production of inflammatory cytokines, type I interferons, and chemokines. We report here on the characterization of a synthetic hexaacylated lipid A derivative, denoted as glucopyranosyl lipid adjuvant (GLA). We assessed the effects of GLA on murine and human dendritic cells (DC) by combining microarray, mRNA and protein multiplex assays and flow cytometry analyses.
View Article and Find Full Text PDFVaccinia virus (VACV) was used as the vaccine strain to eradicate smallpox. VACV is still administered to healthcare workers or researchers who are at risk of contracting the virus, and to military personnel. Thus, VACV represents a weapon against outbreaks, both natural (e.
View Article and Find Full Text PDFIn the last few years, a wealth of information has become available relating to the targets of vaccinia virus (VACV)-specific CD4(+) T cell, CD8(+) T cell and antibody responses. Due to the large size of its genome, encoding more than 200 different proteins, VACV represents a useful model system to study immunity to complex pathogens. Our data demonstrate that both cellular and humoral responses target a large number of antigens and epitopes.
View Article and Find Full Text PDFThe recent identification of a large array of different vaccinia virus-derived CD8(+) T-cell epitopes offers a unique opportunity to systematically analyze the correlation between protective efficacy and variables such as kinetics of expression and function of viral proteins, binding affinity to MHC molecules, immunogenicity, and viral antigen processing/presentation. In the current study, 49 different H-2(b) restricted epitopes were tested for their ability to protect peptide-immunized C57Bl/6 mice from lethal i.n.
View Article and Find Full Text PDFVaccinia virus (VACV) affords long-lasting protection against variola virus, the agent of smallpox. VACV-reactive CD8 T cells contribute to protection but their molecular control is unknown. We show that the TNFR molecule OX40 (CD134) controls primary VACV-specific CD8 T cell expansion and antiviral cytokine production and dictates development of strong memory to both dominant and subdominant VACV epitopes.
View Article and Find Full Text PDFAntibody responses are critical components of protective immune responses to many pathogens, but parameters determining which proteins are targeted remain unclear. Vaccination with individual MHC-II-restricted vaccinia virus (VACV, smallpox vaccine) epitopes revealed that CD4(+) T cell help to B cells was surprisingly nontransferable to other virion protein specificities. Many VACV CD4(+) T cell responses identified in an unbiased screen targeted antibody virion protein targets, consistent with deterministic linkage between specificities.
View Article and Find Full Text PDFUnderstanding immunity to vaccinia virus (VACV) is important for the development of safer vaccines for smallpox- and poxvirus-vectored recombinant vaccines. VACV is also emerging as an outstanding model for studying CD8(+) T cell immunodominance because of the large number of CD8(+) T cell epitopes known for this virus in both mice and humans. In this study, we characterize the CD8(+) T cell response in vaccinated BALB/c mice by a genome-wide mapping approach.
View Article and Find Full Text PDFRecent studies have defined vaccinia virus (VACV)-specific CD8(+) T cell epitopes in mice and humans. However, little is known about the epitope specificities of CD4(+) T cell responses. In this study, we identified 14 I-A(b)-restricted VACV-specific CD4(+) T cell epitopes by screening a large set of 2146 different 15-mer peptides in C57BL/6 mice.
View Article and Find Full Text PDFThe value of predictive algorithms for identifying CD8+ T (T(CD8+))-cell epitopes has not been adequately tested experimentally. Here we demonstrate that conventional bioinformatic methods predict the vast majority of T(CD8+)-cell epitopes derived from vaccinia virus WR strain (VACV-WR) in the H-2(b) mouse model. This approach reveals the breadth of T-cell responses to vaccinia, a widely studied murine viral infection model, and may provide a tool for developing comprehensive antigenic maps of any complex pathogen.
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