Attachment to erythrocytes of uniform salt forms of lipopolysaccharides from Salmonella abortus-equi and its inhibition by various animal sera.

Lipopolysaccharides (LPS) readily attach to erythrocyte membranes in vitro, resulting in hemagglutination in the presence of the homologous bacterial antibodies. The attachment of LPS to red blood cells can be prevented by certain, but not all, animal sera. In this study, the attachment of uniform salt forms of LPS from Salmonella abortus-equi to erythrocytes from various animal species was investigated. The uniform salt preparations were significantly more active than the starting material. Similar findings were obtained with erythrocytes from man, sheep, rabbit, and guinea pig. These results were not due to differences in antibody neutralizing capacity, since all preparations showed essentially identical activity. When sera from various animal species were used as inhibitors of LPS attachment, inhibition of erythrocyte modification by equivalent, but not by identical, amounts of LPS was essentially the same.