IMMUNOGENICITY AND PROTECTIVE ABILITY OF CORPUSCULAR AND SOLUBLE VACCINES PREPARED FROM DIFFERENT COXIELLA-BURNETII PHASE-I STRAINS

BALB/c mice immunized intraperitoneally (ip) with killed purified Coxi ella burnetii phase I corpuscular vaccines or trichloroacetic acid (TC A) extracts from phase I corpuscles (soluble vaccines) were protected against ip challenge with both homologous and heterologous C. burnetii phase I strains. Though the degree of protection, namely the inhibiti on of C. burnetii multiplication in the mouse spleen slightly varied, in general, corpuscular vaccines provided better protection than solub le ones. Cross-protection was accompanied by comparable levels of cell -mediated immune response as evaluated by lymphocyte transformation te st (LTT). However, higher stimulation indices of LTT were obtained wit h homologous than with heterologous strains. The values of antibody re sponse as determined by enzyme-linked immunosorbent assay (ELISA) were higher with homologous strains too. On average, both antibody-inducin g and antibody-binding capabilities of the strains Priscilla and S wer e lower than those of the Nine Mile and Luga strains, except for value s obtained with the antigens from homologous strains.