Because partial protection against
reinfection is induced by experimental
infection in the guinea-pig model of genital chlamydial
infection, we sought to induce immunity by immunization. Female guinea-pigs were immunized subcutaneously with the major outer-
membrane protein (MOMP) and the 61 kDa
cysteine-rich outer-
membrane protein (61 kDa) of the agent of guinea-pig
inclusion conjunctivitis (GPIC) eluted from SDS-
polyacrylamide gels (SDS-MOMP, SDS-61 kDa). Post-immunization sera and secretions contained
antibodies to the SDS-purified
proteins at high titre as measured by immunoblotting, whereas
enzyme immunoassays (EIA) using whole elementary bodies as
antigen showed significantly lower titres (P < 0.001). Likewise, blastogenic responses of peripheral mononuclear cells to GPIC elementary bodies were weak. Animals immunized with SDS-MOMP and SDS-61 kDa were fully susceptible to intravaginal challenge, as were control animals immunized with
buffer without
protein. Another group of animals were immunized with material prepared by extraction of chlamydial outer-membrane complexes with octyl beta-D-glucopyranoside (OGP) and
dithiothreitol, which consisted largely of MOMP (OGP-MOMP). In contrast to the SDS-MOMP group, sera and secretions in the OGP-MOMP group showed high titres in EIA, and high titre
antibodies to MOMP by immunoblot; however, most animals also had
antibodies to 61 kDa, 72 kDa and ca. 84 kDa outer-
membrane proteins. OGP-MOMP animals were partially protected against genital challenge as evidenced by low inclusion scores compared to control animals, although duration of
infection measured by culture isolation was similar to controls.(ABSTRACT TRUNCATED AT 250 WORDS)