Evaluation of three different administration routes (IM, SC and IN) on humoral immune responses against Mycobacterium Tuberculosis ESAT-6/CFP-10 fusion protein

Tuberculosis (TB) has been considered as a main health problems of the present century. Unfortunately, it has been reported different protective responses against BCG vaccine, as only available vaccine against TB .The search for a new and improved vaccine against tuberculosis is currently a very active field of research. In this study, we have evaluated the relative effects of intranasal (i.n), subcutaneous (s.c) and intramuscular (i.m) routes of immunization on the induction of humoral immune responses against TB recombinant protein.
The recombinant ESAT-6/CFP-10 antigens has been assessed and confirmed preliminary, for this study. The Balb/C mice were immunized in 3 different routes, three times at 2-week intervals with recombinant protein, formulated with or without adjuvants (MF-59 for the i.m and s.c routes and CTB for i.n). Blood was collected from retro-orbital sinus 10 days after each immunization and after separation of sera, they were evaluated for specific antibodies against antigen by an indirect ELISA method, which had set up during the research.
Mice vaccinated against recombinant proteins had high level of specific antibodies compared to the controls. Our results showed that although the i.m and s.c injections also induce immune responses, but the antibody titer in i.n rout had graduately elevated to reach in acceptable levels.
The results could be used for formulation of mucosal vaccines against tuberculosis in future studies.