Submitted to: Veterinary Immunology and Immunopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 12, 1997
Publication Date: N/A
Interpretive Summary: The Second International Swine CD Workshop was held over the last 3 years to establish a panel of internationally recognized monoclonal antibodies (mAbs) which react with porcine lymphoid cells. This manuscript describes the characterization of the set of mAbs which react with the CD8 subset of T cells. This cell subset is best known because of the ability of many CD8+ cells to kill virus infected cells. In the workshop, 57 mAbs were reactive with T cells and only 3 mAbs assigned to the CD8 T cell/ activation marker cluster T9 along with the two wCD8 workshop standard mAbs. The reactivity of the new mAbs with the CD8 cell surface marker was verified through the use of two color cell binding studies and molecular weight analyses, after which the new mAbs were given the wCD8 designation. The reactivity of another mAb PG164A proved that it had a unique pattern, i.e., that it not only exclusively reacted with CD4-/CD8high lymphocytes, but it also failed to recognize CD4+/CD8+ double positive lymphocytes; thus, it was given the wCD8c designation. This latter mAb will be very useful as a way to identify only the CD8 molecule expressed on these double positive T cells, that are thought to be the memory T cells so important for effective disease and vaccine responses. These anti-CD8 mAbs will be important in defining the role of CD8+ lymphocyte subsets in swine health and in designing new methods to prevent diseases.
Based on an analysis of their reactivity with porcine peripheral blood lymphocytes (PBL), only 3 of 57 monoclonal antibodies (mAbs), assigned to the T cell/activation marker group of the Second International Swine CD Workshop, were grouped into cluster T9 along with the two wCD8 workshop standard mAbs 76-2-11 (CD8a) and 11/295/33 (CD8b). Their placement was verified through the use of two color cytofluorometry which established that all 3 mAbs bound exclusively to CD8+ cells and reacted with of 33 and 35 kDa proteins, and were thus given the wCD8 designation. Because the mAb STH101 inhibited the binding of mAb 76-2-11 but not of 11/295/33, it was given the wCD8a designation. The reactivity of the other two new mAbs in the T9 cluster with the various subsets of CD8+ lymphocytes were distinct from that of the other members in this cluster including the standards. The mAb PG164A not only exclusively reacted with CD4-/CD8high lymphocytes, but it also failed to recognize CD4+/CD8+ double positive lymphocytes; it was thus given the wCD8c designation. Overall, five new wCD8 mAbs were identified. Although the molecular basis for the differences in PBL recognition by these mAbs is not yet understood, they will be important in defining the role of CD8+ lymphocyte subsets in health and disease.