Fig. 3
Optimized SLA-LSQ adjuvant formulations induce persistent functional immunity in mice. Following a single immunization of WN-80E (1 µg) with or without SLA-LSQ adjuvant (5 µg SLA/2 µg QS21), we investigated the longevity and functionality of antiviral antibody responses. Seven days post-immunization, and consistent with previous findings, we observe an adjuvant-dependent stimulation of CD4+ T cells a and germinal center B cells b. In addition, LSQ induced an increase in the number of WN-80E specific IgG+ antigen-secreting cells (ASC) in the bone marrow 21 days post-immunization. Consistent with induction of a Th1 CD4+ T-cell response, we find a significant increase in the number of IgG2c+ ASC at this timepoint c. Serum was periodically collected from immunized animals for up to 300 days. LSQ adjuvant stimulated a potent virus neutralizing response that peaked 63 days post-injection, and persisted for up to 300 days d. Three hundred days post-injection, all animals were challenged with 105 PFU of WNV (NY385-99 strain). Animals immunized with SLA-LSQ adjuvanted vaccine showed 100% survival, while those immunized with WN-80E alone showed survival similar to naïve controls e. Bars in a represent mean percentages of cytokine-positive cells (n = 5/group), and error bars reflect standard deviation of the mean. Statistical significance was determined against WN-80E immunized animals by one-way ANOVA (*p < 0.05, **p < 0.005, ***p < 0.0005,****p < 0.0001)
