MONOCLONAL-ANTIBODY AGAINST YELLOWTAIL THYMIC LYMPHOCYTES RECOGNIZINGA LYMPHOCYTIC SUBPOPULATION

Monoclonal antibody (mAb) YeT-2 was generated in mice hyper-immunized with thymic lymphocytes of yellowtail Seriola quinqueradiata. The mAb YeT-2 reacted with the major population of peripheral blood lymphocyte s, but not with serum IgM. On Percoll density gradient centrifugation, YeT-2 positive cells were distributed at densities of 1.058 and 1.064 . The latter density layer also included some YeT-2 negative cells. Fu rthermore, on electron microscopic studies, YeT-2 positive lymphocytes in peripheral blood could not be distinguished from YeT-2 positive ly mphocytes in thymus. Flow cytometric analysis showed that mAb YeT-2 po sitive lymphocytes comprised 88.4% and 76.1% of the peripheral blood a nd thymus, respectively. Functional studies revealed that YeT-2 positi ve lymphocytes respond to concanavalin A but not to lipopolysaccharide , while YeT-2 negative lymphocytes responded in the opposite way. From these results, it can be concluded that the novel mAb YeT-2 recognize s a lymphocytic population which might be the putative T cell.