title: The monoclonal antibody CZ-1 identifies a mouse CD45-associated epitope expressed on interleukin-2-responsive cells.
abstract: We have previously described a monoclonal antibody (mAb), CZ-1, which reacts with an epitope expressed on most peripheral basophils, natural killer cells, B cells, and CD8+ T cells, but not with most thymocytes or peripheral CD4+ T cells. Here we show that mAb CZ-1 defines a sialic acid-dependent epitope associated with a subpopulation of CD45 molecules. This conclusion is based on the ability to block binding of mAb CZ-1 by sialic acid, neuramin-lactose, neuraminidase, and mAb to CD45RB, and by expression of the epitope on transfected psi 2 cells expressing exon B of CD45. The results suggest that the CZ-1 epitope is a post-translational modification expressed on a subpopulation of the CD45 molecules also expressing the B exon. Expression of the CZ-1 epitope was required for freshly isolated lymphocytes to respond to interleukin-2 (IL-2). Depletion of CZ-1+ cells by C' or by cell sorting of thymocytes or splenocytes eliminated the IL-2 responsive cells. The subpopulations of thymocytes and CD4+ splenocytes responding to IL-2 were exclusively within the small CZ-1+ subpopulation. mAb CZ-1 was also used to subdivide CD45+ and CD45RB+ splenocytes into IL-2-responsive and -nonresponsive subpopulations. The CZ-1 epitope was also expressed on virtually all lymphokine-activated killer cell precursors. These data, thus, indicate that cells responsive to IL-2 express this sialated modification of CD45.
authors.affiliation: Department of Pathology, University of Massachusetts Medical Center, Worcester 01655.
authors.forename: R R
authors.initials: RR
authors.lastname: Brutkiewicz
authors.forename: C L
authors.initials: CL
authors.lastname: O'Donnell
authors.forename: J W
authors.initials: JW
authors.lastname: Maciaszek
authors.forename: R M
authors.initials: RM
authors.lastname: Welsh
authors.forename: M
authors.initials: M
authors.lastname: Vargas-Cortes
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000378:metabolism; D001667:Binding, Competitive; D002455:Cell Division / Q000187:drug effects; D000939:Epitopes / Q000235:genetics / Q000378:metabolism; D007376:Interleukin-2 / Q000494:pharmacology*; D015979:Killer Cells, Lymphokine-Activated / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D017493:Leukocyte Common Antigens / Q000235:genetics / Q000378:metabolism*; D007962:Leukocytes / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D008213:Lymphocyte Activation; D051379:Mice; D008810:Mice, Inbred C57BL; D019158:N-Acetylneuraminic Acid; D011499:Protein Processing, Post-Translational; D012794:Sialic Acids / Q000378:metabolism; D014162:Transfection
chemical_list: D000911:Antibodies, Monoclonal; D000939:Epitopes; D007376:Interleukin-2; D012794:Sialic Acids; D017493:Leukocyte Common Antigens; D019158:N-Acetylneuraminic Acid