Porcine CD5 gene and gene product identified on the basis of inter-species conserved cytoplasmic domain sequences

Analysis of published CD5 amino acid sequences identified conserved sequences with potentially immunogenic epitopes. To obtain anti-porcine CD5, synthetic peptides representing conserved sequences identified in mouse, human, cattle and sheep CD5 cytoplasmic tail domains were linked to KLH and used to immunize rabbits. Anti-synthetic peptide serum reacted with an antigen extracted from porcine lymphocyte membrane which was consistent in size (67 kDa) with CD5. Murine monoclonal anti-porcine wCD5 (b53b7) and the anti-CD5 synthetic peptide serum react with the same ligand confirming that porcine wCD5 has conserved amino acid sequences similar to those of CD5 of several species. Analysis of porcine genome for CD5 gene sequences by PCR was conducted to verify the presence of CD5-like genes. Oligomeric primers were designed to identify CD5-like sequences by polymerase chain reaction in pigs and other species. Amplified DNA similar in size to that predicted for CD5 elements were amplified from a variety of animal genomes including that of pig. The porcine-derived fragment was cloned and shown to be 96% similar to mouse CD5. The use of published CD sequences for prediction of immunogenic peptides has provided a complimentary alternative to the more traditional approaches to production of CD-specific antibodies.