PORCINE CD3-EPSILON - ITS CHARACTERIZATION, EXPRESSION AND INVOLVEMENT IN ACTIVATION OF PORCINE T-LYMPHOCYTES

The cloning, characterization and expression of porcine CD3 epsilon an d establishment of its role in T-cell activation using an anti-porcine CD3 epsilon monoclonal antibody, as described here, provides a first step towards a greater understanding of the porcine immune response. P orcine CD3 epsilon was cloned from a porcine T-cell cDNA library by po lymerase chain reaction and found to have up to 72% identity with othe r CD3 epsilon chains, retaining all the necessary primary structural m otifs for correct functioning of porcine CD3 epsilon. When expressed i n COS7 cells porcine CD3 epsilon was an intracellularly localized, mon omeric 23 000 MW protein exhibiting no evidence of N-glycosylation. A monoclonal antibody, PPT3, recognized expressed porcine CD3 epsilon an d activated porcine T cells as demonstrated by stimulation of calcium mobilization, an increase in protein tyrosine phosphorylation and prol iferation. These results further reaffirm and identify CD3 epsilon as an important cell surface protein involved in signal transduction of a ctivation signals in porcine T cells.