Molecular restriction of anti-DNP antibodies induced by (DNP)2-gramicidin S

The molecular properties of anti-DNP antibodies were studied in 80 rabbits hyperimmunized with (DNP)2-gramicidin S. Unimmunized animals or those previously skin-painted with DNFB were subjected to biweekly injections of (DNP)2-gramicidin S. Isoelectric focusing revealed that the spectrotypes of the anti-DNP antibodies fell into three classifications; monoclonal, 18 to 21%; biclonal, 21 to 30%; and restricted, 14 to 26%. In each immunization protocol 35% of the rabbits did not respond. Longer time periods and more intensive immunization were necessary to achieve and anti-DMP response than with conventional DNP-protein conjugates, with skin painting tending to shorten the overall response time. The anti-DNP responses were invariant with respect to affinity and isoelectric spectra regardless of the immunization protocol or degree of restriction. Chain reassociation studies on antibodies purified from the sera of rabbits displaying monoclonal spectrotypes provide additional evidence that such antibodies are biosynthetically homogeneous. These data support the concept that carrier complexity influences the heterogeneity of the anti-hapten response but strongly suggests that the genetics of an outbred population may be an overriding factor in controlling response heterogeneity.