The cholera vaccine projected here consists of an aqueous mixture of two purified proteins of Vibrio cholerae, namely (i) C4-dicarboxylate-binding periplasmic cum outer membrane protein (DctP, VC1929) and (ii) outer membrane protein (TolC, VC1565). Both antigens were characterized as colonizing antigens of V. cholerae and mutants not expressing these proteins were attenuated in virulence (1,2).

Purified LPS-free DctP and TolC proteins isolated from V. cholerae 01 were evaluated as vaccine against cholera in animal models. The vaccine carrying the two colonizing antigens in  an aqueous suspension was delivered on the nasal mucosa of adult rabbits. Vibriocidal antibodies , circulating IgG and secretary IgA corroborate with protection to challenge in

ileal loops of immunized adults rabbits. Subaccute and acute toxicity together with mucous membrane irritancy studies in rats and rabbits by nasal route suggest safety of vaccine.

1. A. Jacob et al., Vaccine 11, 376 (1993).

2. S. N. Singh et al., Microbial Pathogenesis 17, 69 (1994).