SDS-PAGE analysis of purified Cowpea severe mosaic virus (CPSMV) revealed the migration of three protein fractions of 43, 23 and 21 kDa, corresponding to the capsid protein called large protein (43 kDa) and small protein (23 kDa; intact and 21 kDa; cleaved). The capsid proteins, in their native form, were used to immunize mice through oral and nasal routes for ten consecutive days. The denatured form of the 43 and 23 kDa protein fractions were used for subcutaneous immunization. The mucosal immune response was detected by the cellular proliferation of the Peyer's patches of mice immunized by oral route with CPSMV. It was demonstrated that CPSMV induces immune response, evidenced by the synthesis of specific antibodies, when administered in the native form by the oral and nasal routes or with two denatured capsid proteins by the subcutaneous route. The use of adjuvants in the oral and nasal immunizations was not necessary. The 43 and 23 kDa protein fractions were responsible for the immunogenicity of the virus, evidenced by the synthesis of specific antibodies detected by ELISA test. The cellular proliferation analysis of the Peyer's patches revealed an increase (r=0.88) of leucocytes along 42 days after immunization. The results reinforce the possibility of the use of CPSMV as a safe vector of antigens for human/animal diseases of low immunogenicity for the production of vaccines.
Comovirus; nasal immunization; oral immunization; vaccine; viral vector
