title: Expression of the rat CD26 antigen (dipeptidyl peptidase IV) on subpopulations of rat lymphocytes.
abstract: The T cell activation antigen CD26 has been recently identified as the cell surface ectopeptidase dipeptidyl peptidase IV (DPP-IV). DPP-IV is found on many cell types, including lymphocytes, epithelial cells, and certain endothelial cells. The MRC OX61 monoclonal antibody (MAb) which specifically recognises rat DPP-IV was used to examine the expression of CD26/DPP-IV on rat lymphocytes. The molecular nature of the antigen was examined by immunoprecipitation from thymocytes, splenocytes, and hepatocytes. Analysis by one- and two-dimensional gel electrophoresis indicated that the native form of CD26 includes a 220-kDa homodimer. On tissue sections MRC OX61 MAb stained nearly all thymocytes and in the spleen and lymph nodes predominantly stained the T cell areas. However, in immunofluorescence experiments OX61 stained 80 to 87% of lymph node cells and 78 to 85% of spleen cells. Furthermore, two-colour immunofluorescence analysis of the CD4+, CD8+, and Ig+ lymphocyte subsets indicated that only 2 to 5% of each of these subsets lacked OX61 staining. Spleen cells and thymocytes of both CD4+ and CD8+ subsets stained much more intensely with OX61 after these cells were stimulated with phytohemagglutinin. These findings indicate that rat CD26 antigen expression is not confined to the T cell population as has been suggested, but also occurs on B cells, and is increased on T cells following their activation.
authors.affiliation: A.W. Morrow Gastroenterology and Liver Centre, Royal Prince Alfred Hospital, Sydney, Australia.
authors.forename: M D
authors.initials: MD
authors.lastname: Gorrell
authors.forename: J
authors.initials: J
authors.lastname: Wickson
authors.forename: G W
authors.initials: GW
authors.lastname: McCaughan
mesh_terms: D000818:Animals; D000945:Antigens, Differentiation, T-Lymphocyte / Q000737:chemistry / Q000378:metabolism*; D018819:Dipeptidyl Peptidase 4; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / Q000737:chemistry / Q000378:metabolism*; D015180:Electrophoresis, Gel, Two-Dimensional; D005434:Flow Cytometry; D007150:Immunohistochemistry; D008213:Lymphocyte Activation; D016131:Lymphocyte Subsets / Q000201:enzymology / Q000276:immunology*; D008970:Molecular Weight; D051381:Rats; D014018:Tissue Distribution
chemical_list: D000945:Antigens, Differentiation, T-Lymphocyte; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases; D018819:Dipeptidyl Peptidase 4