Multivariate analysis of the immune response to different rabies vaccines.

In a previous study, we proposed as an alternative to the use of animals in infectious challenge studies, a new approach describing the vaccine-induced immune response through the multivariate analysis of a defined set of immune parameters characterizing the B and T immune responses. This multivariate analysis, i.e. immune fingerprint, was evaluated first to assess the impact of minor changes in well characterized vaccines. The approach showed promising results in the assessment of the compatibility between two licensed vaccines. In the present study, the immune fingerprint was used to compare adjuvants with the various immunological parameters of the immune fingerprint as well as to assess the ability of this approach to discriminate different Rabies vaccine formulations in dogs. RABISIN® was the reference vaccine, adjuvanted with aluminum hydroxide. An exploratory factor analysis was used to analyse the covariance structure of the immunological data. Significant differences were observed between groups. RABISIN and a linear polyacrylate (SPA09) adjuvanted vaccine performed better than chitosan adjuvanted ones, both for humoral and cell immune responses. This study showed that the immune fingerprint approach can be used to screen vaccine formulations. It provides additional information compared to classical vaccination and infectious challenge efficacy study.