M. Lagranderie et al., ORAL IMMUNIZATION WITH RECOMBINANT BCG INDUCES CELLULAR AND HUMORAL IMMUNE-RESPONSES AGAINST THE FOREIGN ANTIGEN, Vaccine, 11(13), 1993, pp. 1283-1290
It has been shown recently that BCG can be used as a live recombinant
vaccine to stimulate immune responses. Proliferative or cytotoxic T-ce
ll responses against several viral proteins such as HIV Gag, Env or Ne
f were obtained after parenteral immunization with BCG expressing thes
e proteins. Antibody responses were also obtained after immunization o
f mice with recombinant BCG strain which expressed lac Z under the con
trol of a promoter sequence isolated from Mycobacterium paratuberculos
is. We have used this recombinant vaccine in guinea-pigs to investigat
e the influence of various routes of immunization on the immunogenicit
y of a foreign antigen expressed by recombinant BCG. Guinea-pigs were
immunized by oral, respiratory or intradermal routes and proliferative
responses, delayed-type hypersensitivity and antibody responses speci
fic for beta-galactosidase were followed for 16 weeks. Results demonst
rated that humoral and cellular immune responses specific for beta-gal
actosidase can be produced in all groups of guinea-pigs. However, the
respiratory and especially the oral route of administration induced hi
gher local and systemic immune responses than the intradermal route of
immunization. Moreover, the oral immunization of mice with this recom
binant BCG induced IgA responses which could be detected in both sera
and intestinal secretions. Therefore, this study demonstrates for the
first time that oral immunization with recombinant BCG can induce stro
ng cellular and humoral immune responses.