Inheritance of antibody specificity: the IgM anti-lipopolysaccharide response in mice

Mice of different genotypes were immunized with Salmonella anatum. The cross-reactivity patterns of their IgM anti-S. anatum lipopolysaccharide (LPSAN) antibodies were characterized by their relative avidity toward heterologous LPS. When the LPS from S.cholera suis (LPSCHS) was used as the heterologous LPS, clear differences between mouse strains were found. DBA/2 and DBA/1 showed cross-reacting IgM, whereas C57BL/10, C57BL/6 BABL/c-Igb and B10. D2 had mainly noncross-reacting IgM. In C3H and C57BL/6-Iga, individual mice express either the cross-reacting or the noncross-reacting antibodies. The IgM antibodies from individual mice were further characterized for their cross-reactivity toward the LPS from S. strasbourg (LPSSTR) and S illinois (LPSILL). Only individual patterns with no correlation to the cross-reactivity pattern with LPSCHS were found.This shows that more than one antibody type is characterized by cross-reactivity.(B10.D2 X DBA/1)F1 mice showed a biphasic distribution of cross-reactivity. Of the F1 X DBA backcross mice 21% had IgM antibodies which showed no cross-reaction with LPSCHS. This still is in agreement with one locus controlling this phenotype. This locus segregates independently from Ig allotype since no correlation was found between allotype and cross-reactivity pattern in F1 X DBA backcross mice.