INVESTIGATIONS INTO THE UBIQUITOUS NATURE OF HIGH OR LOW IMMUNE RESPONSIVENESS AFTER DIVERGENT SELECTION FOR ANTIBODY-PRODUCTION IN COMMON CARP (CYPRINUS-CARPIO L)

This paper reports on the selection of individual carp with a high or low antibody response, in combination with reproduction by gynogenesis , in order to develop well-characterised inbred carp lines consisting of practically unlimited numbers of carp with the same genotype. Two h omozygous progenies, previously characterised as having a high or low immune response to dinitrophenyl keyhole limpet haemocyanin (DNP-KLH), were immunised with either a T-dependent (DNP-human serum albumin (DN P-HSA)) or T-independent (trinitrophenyl lipopolysaccharide (TNP-LPS)) hapten-carrier complex. In comparison with the antibody response afte r DNP-KLH immunisation, the response to DNP-HSA was observed to be hig hly variable and did not differ between the divergently selected proge nies. This suggests that the divergent selection for antibody producti on to DNP-KLH has been carrier-specific. Immunisation with T-independe nt TNP-LPS induced a very rapid response which differed between the hi gh and low responders, and likely measured changes in the DNP-specific precursor pool of B cells caused by the selection. A number of select ed individuals with a high immune response to DNP-KLH were infected wi th Trypanoplasma borreli, a haemoflagellate parasite of carp, to exami ne a possible relationship between the increase in immune responsivene ss and disease resistance, but no change could be detected. However, i ndividual homozygous carp were able to escape inbreeding depression an d survive the infection. Such carp would be likely candidates for gyno genetic reproduction to obtain viable inbred carp lines.