title: Differentiation between MHC-restricted and non-MHC-restricted porcine cytolytic T lymphocytes.
abstract: The immune system of swine is unique in that the expression of CD4 and CD8 antigens defines four subpopulations of resting extrathymic T lymphocytes. Beyond phenotypic differences to other species, porcine T lymphocytes, particularly when derived from infected animals, are known to show high non-specific cytolytic in vitro activity. Here we describe the putative porcine CD6 antigen (workshop CD6; wCD6) which enables a phenotypic separation of T lymphocytes responsible for major histocompatibility complex (MHC)-restricted and non-MHC-restricted cytotoxicity. The putative porcine CD6 analogue, wCD6, a protein with a molecular mass of 110,000, shows high specificity for T lymphocytes and is neither expressed on B lymphocytes nor on cells of the myeloid lineage. In the extrathymic T-lymphocyte compartment wCD6 characterizes two T-lymphocyte fractions: wCD6+ T lymphocytes including both CD4+ T-helper cell subpopulations (CD4+CD8- and CD4+CD8+) and within the CD4-CD8+ fraction cells with high CD8 antigen density. In contrast the CD4-CD8- gamma/delta T-cell receptor (TCR) subset and CD4-CD8+ cells with low CD8 antigen density are included in the wCD6- T-lymphocyte fraction. Functional studies with separated wCD6 fractions revealed that the wCD6- cells can be characterized by spontaneous and non-MHC restricted cytolytic activity, whereas the wCD6+ T lymphocytes are responsible for MHC-restricted T-cell functions. Thus, the porcine wCD6 is an important antigen to discriminate between MHC-restricted and non-MHC-restricted cytotoxicity.
authors.affiliation: Federal Research Centre for Virus Diseases of Animals, Tübingen, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Pauly
authors.forename: E
authors.initials: E
authors.lastname: Weiland
authors.forename: W
authors.initials: W
authors.lastname: Hirt
authors.forename: C
authors.initials: C
authors.lastname: Dreyer-Bux
authors.forename: S
authors.initials: S
authors.lastname: Maurer
authors.forename: A
authors.initials: A
authors.lastname: Summerfield
authors.forename: A
authors.initials: A
authors.lastname: Saalmüller
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000276:immunology*; D000945:Antigens, Differentiation, T-Lymphocyte / Q000276:immunology*; D002469:Cell Separation; D003601:Cytotoxicity Tests, Immunologic; D005434:Flow Cytometry; D007150:Immunohistochemistry; D008285:Major Histocompatibility Complex / Q000276:immunology*; D013552:Swine / Q000276:immunology*; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*
chemical_list: D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; C062279:CD6 antigen