INTESTINAL IMMUNIZATION OF MICE WITH ANTIGEN CONJUGATED TO ANTI-MHC CLASS-II ANTIBODIES

We have explored a new technique for immunization of the intestinal tr act of mice, using protein antigens bound to antibodies with specifici ty for murine MHC class II molecules (MHC-II). Either of two protein a ntigens, hen avidin (AV) or hen egg lysozyme (HEL) were covalently con jugated to anti-MHC-II antibodies and the purified conjugates were giv en orally (p.o.) or by direct intraduodenal (i.d) injection into the i ntestinal lumen of mice. A secondary immunization p. o. with the same conjugate or with the non-conjugated antigen in the presence of choler a toxin (CTX) resulted in production of both intestinal secretory IgA and serum IgA antibody by those mice, In addition, serum IgG antibodie s were produced Conjugates with appropriate MHC-II specificity targete d the antigen because they induced more IgA and IgG antibody than conj ugates with irrelevant antibody specificity or antigen alone, and beca use they induced antibody in mice that were genetic low responders to antigen. The results indicate the feasibility of oral subunit type vac cines with antibody targeting technology.