Tumor-selective cytolysis is executed exclusively by CD45R+ CTL whereas allo-specific cytotoxicity can be executed also by CD45R- CTL.
Naive and memory CD4+ T helper cells can be distinguished on the basis of expression of the CD45R molecule. Whether this dichotomy applies also to CD8+ T cells has not yet been established. In the present investigation the cytolytic activity of peritoneal CD8+CD45R+ and CD8+CD45R- T cells from tumor- and allo-immunized rats has been studied. More than 90% of the CD8+ peripheral blood T lymphocytes expressed the CD45R molecule, whereas in the peritoneal cavity about 60% of the CD8+ T cells displayed the CD45R+ phenotype. Analysis of cytotoxicity of sorted peritoneal cells of W439 tumor-immunized donors demonstrated selective cytolytic activity of the CD5+CD4-CD8+CD45R+ subpopulation to W439 lymphoma target cells but no effect of CD5+CD4-CD8+CD45R- lymphocytes. None of these lymphocyte populations exhibited cytolytic activity to the NK-sensitive cell line YAC-1, whereas the CD5-CD45R+ population showed strong cytotoxicity to YAC-1 cells. In allo-immunized rats both CD5+CD4- CD8+CD45R+ and CD5+CD4-CD8+CD45R- peritoneal cells exhibited strong allo-specific cytolytic activity, but no activity to YAC-1 cells. Both CD5+CD4-CD8+CD45R+ and CD5+CD4-CD8+CD45R- cells from tumor-immunized rats proliferated in response to Con A and rIL-2. This is the first study demonstrating that tumor-selective cytolytic CD8+ T cells express the CD45R molecule and that allo-specific cytolytic CD8+ T cells are found in both the CD45R+ and CD45R- populations.
Ericsson
P O
PO
Department of Tumor Immunology, University of Lund, Sweden.
Hedlund
G
G
Hansson
J
J
Dohlsten
M
M
Sjögren
H O
HO
D000818:Animals; D015703:Antigens, CD / Q000032:analysis*; D000943:Antigens, Differentiation / Q000032:analysis*; D003602:Cytotoxicity, Immunologic; D007114:Immunization; D017493:Leukocyte Common Antigens; D008213:Lymphocyte Activation; D009374:Neoplasms, Experimental / Q000276:immunology*; D051381:Rats; D011919:Rats, Inbred Strains; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*
D015703:Antigens, CD; D000943:Antigens, Differentiation; D017493:Leukocyte Common Antigens