Structural and serological relationships among different antibodies from the same rabbit antiserum. I. Isolation, chemical and allotypic characterization of ten antibody components from one anti-streptococcal serum.

The relationships among antibodies produced by an individual rabbit were examined using multiple antibodies elicited by hyperimmunization with Group C streptococcal vaccine. Immunoadsorbent chromatography followed by agarose block electrophoresis yielded nine different antibody fractions, all directed against Group C carbohydrate, from the immune plasma of rabbit 4295 (allotype a1/b5). Electrophoresis of the antibody light chains gave single bands for most of the antibodies. Amino acid sequence analyses carried out on several of the antibody L-chains revealed that five of these had aspartic acid at the amino terminus. By quantitative allotypic analyses all antibodies were allotype a1/b5. One antibody fraction, homogeneous by all other criteria, contained antibodies with two distinct group a allotypic subspecificities. The two antibodies in this fraction could be separated on an anti-a1 column. The ten antibodies were placed into a minimum of three groups based on differences in a1 allotype subspecificity.