[Possible common partial antigens in human Ig allotype structure and ubiquitous bacteria, studied with the example of...

As can be learned from the literature, bovine serum may contain antibodies directed against human immunoglobulin allotypes. This gave rise to the question of what the origin of those antibodies is. We tested bacteria (E. coli) by means of the haemagglutination inhibition assay, which is used to type either Gm or Km factors. Anti-G1m(2) and anti-G3m(10)-specific antibodies were inhibited by the bacteria in a clear-cut manner, as was anti-Km(1), albeit less significantly. In contrast, the bacteria tested almost totally failed to inhibit anti-G3m(21) serum. The results lead to the assumption that E. coli may carry both Gm- and Km-like antigenic structures, which are presumably the antigenic material leading to immunization of cattle. Furthermore, new attention is drawn to a mechanism for immunization which is discussed regarding the genesis of either AB0 isoagglutinins in man or other "naturally occurring" antibodies.