Differences in the constitution of antibody combining site in different mice strains

Anti‐2,4‐dinitrophenyl (DNP) antibodies from nine different inbred mice strains were affinity labeled with four bromoacetyl derivatives of DNP haptens. Strain related differences in the number of combining sites labeled, as well as in the relative amount of labeled tyrosine and lysine were observed. Differences in the relative ratio of residues labeled did not change much with size of reagent and may be related to subpopulations of antibodies differing in the constitution of their combining sites.