Effect of adjuvants and route of immunizations on the immune response to recombinant plague antigens

Abstract

In this study, we compare four different adjuvants, LT(R192G), CpG ODN, MPL ® TDM and alum, for their ability to affect the magnitude, distribution, and duration of antibody responses against F1-V, the lead-candidate antigen for the next generation vaccine against plague, in a murine model. In addition, three different routes of immunization -intranasal (IN), transcutaneous (TC), and subcutaneous (SC), were compared with each adjuvant. Since aerosol exposure to biological warfare agents is of primary concern, both serum and bronchioalveolar lavage (BAL) were analyzed for antigen-specific antibody responses. The most significant findings of the study reported here are that 1) the adjuvant influences the Type 1/Type 2 balance of the antibody response in both the serum and BAL, 2) mucosal immunization is not necessary to obtain F1-V-specific BAL responses, 3) nontraditional adjuvants such as LT(R192G) work when delivered SC, 4) the route of immunization affects the magnitude of the immune response, and 5) F1-V is highly immunogenic by some routes even in the absence of an exogenously applied adjuvant. These studies provide important insights into the influence of different classes of adjuvants on the immune outcome in biodefense vaccines and for development of new generation vaccines against other pathogens as well.

Protective Immunity in Mice Achieved with Dry Powder Formulation and Alternative Delivery of Plague F1-V Vaccine

“…Consistent with the previous studies (18,28,35), serum antibody responses and protective efficacy following two doses of nasal vaccine were lower than those following i.m. or i.d.…”

The A Subunit of Escherichia coli Heat-Labile Enterotoxin Functions as a Mucosal Adjuvant and Promotes IgG2a, IgA, and Th17 Responses to Vaccine Antigens

“…The quantitative GM1 binding enzyme-linked immunosorbent assay (ELISA) was performed as previously described (26,58). Briefly, wells were coated with 10 g of GM1 monosialoganglioside (Sigma) each prior to addition of samples or were coated directly with 0.1 g of LT, A, A1, or B.…”

“…Quantitative anti-TT and anti-OVA ELISAs were performed on individual serum, BAL fluid, and fecal samples as previously described (26,58), with wells coated with 0.1 g of antigen each. For Th17 analysis, an antigen restimulation assay was performed using splenocytes isolated and cultured at 1 ϫ 10 5 cells with 0.1 g/well antigen (OVA or TT) in a 96-well plate with 200 l medium.…”

Prophylactic Administration of Bacterially Derived Immunomodulators Improves the Outcome of Influenza Virus Infection in a Murine Model

“…Studies in vivo have also shown that intranasal delivery of CT-B, the binding subunit of the enterotoxin, combined with minimal levels of CT holotoxin, induces protective effects in influenza virus-infected mice (49). In contrast to CpG and CT, LT and LT(R192G) induce a more balanced cytokine and antibody subclass profile indicative of a mixed Th1/Th2 immune response (16,45,73). LT(R192G) has yet to be evaluated as a prophylactic immunomodulator, but another LT mutant, LT(S63K), has demonstrated some protective effects against influenza virus, respiratory syncytial virus (RSV), and Cryptococcus neoformans infections (80).…”