The appearance of IgM and IgG cold agglutinins in rabbits hyperimmunized with group C streptococcal vaccine
Colling, R.G.; Brown, J.C.
Journal of Immunology 122(1): 202-208
1979
ISSN/ISBN: 0022-1767 PMID: 84018 Document Number: 153802
Rabbits hyperimmunized with Group C streptococcal vaccine developed Ig preparations exhibited maximum agglutinating activity toward human type O and rabbit RBC when assayed at 4.degree. C, significant agglutinating activity toward human type A and sheep RBC was observed when the preparations were assayed at 37.degree. C. The cold agglutinins isolated by thermal elution from rabbit RBC were effective hemolysins; less than 1.0 .mu.g of IgM was required to sensitize rabbit RBC for 50% lysis in the presence of guinea pig complement (C) in a biphasic-temperature lysis assay. Saccharide haptens, group-specific carbohydrate and soluble blood group substances were examined for their ability to effect inhibition of lysis. The most effective overall inhibitor was Group C streptococcal carbohydrate, whereas the most effective hapten inhibitor was N-acetylgalactosamine. Of the soluble blood group substances tested, hog mucin H-substance (1st Smith degradation product) was slightly more inhibitory than hog mucin A + H-substance but substantially more active than human ovarian cyst material. Although the soluble blood group substances were capable of competing for rabbit RBC determinants, none gave a visible precipitate in the presence of cold agglutinin when assayed by Ouchterlony double diffusion. Significant precipitation occurred when cold agglutinin was examined in the presence of Group C carbohydrate in precipitin assays and by Ouchterlony analyses. The cold agglutinins produced in rabbits hyperimmunized with Group C streptococcal vaccine may be a population of group carbohydrate-specific Ab that are cross-reactive with I antigen-like determinants present on rabbit and human RBC.