Antibody response to dinitrophenyl hapten by foetal, neonatal and young pigs

The immunological competence of foetal (85 days of gestation), neonatal and older pigs has been assessed by their ability to make heterogeneous IgG antibody to dinitrophenyl (DNP) hapten. Antibody heterogeneity was resolved by isoelectric focusing (IEF) followed by overlay of labelled antigen. Choice of protein carrier (bovine serum albumin, keyhole limpet haemocyanin or ovalbumin) had little effect on anti-DNP responses. Pigs of all three ages were capable of producing isoelectrically heterogeneous antibody which did not become more diverse, either with repeated immunization or with increasing age. Foetal pigs did not all respond equally strongly as assessed by IEF, but those with clearly heterogeneous antibody showed IEF patterns similar to 'adult' type anti-DNP. This demonstrates that by 85 days of gestation the pig foetus is capable of a mature response to an antigen which is T-dependent in rodents.