title: Anti-leucocyte common (CD45) antibodies inhibit dendritic cell stimulation of CD4 and CD8 T-lymphocyte proliferation.
abstract: Dendritic cells (DC) act as primary antigen-presenting cells and probably initiate T-cell responses via the formation of DC-T-cell clusters. Both DC and T cells express members of the leucocyte common (CD45) family of molecules as major cell membrane proteins. The possibility that the leucocyte common antigens (LCA) play a functional role in the cellular events of a primary T-cell response was tested, by examining the effect of CD45 antibodies on the T-cell proliferative response induced by stimulating with allogeneic DC in the mixed leucocyte reaction (MLR). The presence of individual CD45 monoclonal antibodies during the MLR inhibited T-cell proliferation only weakly, but a mixture of monoclonal antibodies against different epitopes of the LCA had a more profound inhibitory effect. The effect of the CD45 antibodies was maximal during the first 24 hr and preincubation experiments indicated that the major blocking effect occurred at the T-cell level, although some inhibition after preincubation with DC was noted. Purified allogeneic CD8 T-cell responses were more susceptible to inhibition than purified CD4 cell responses, but no difference in the inhibition of the CD45RA (CMRF-11) or CD45RO (UCHL1) LCA-positive T-cell subsets was observed. The presence of CD45 antibodies did not inhibit DC-T-cell clustering but reduced cluster stability, suggesting that certain epitopes of the LCA may be involved in the process of cell adhesion.
authors.affiliation: Haematology Department, Christchurch Hospital, New Zealand.
authors.forename: T C
authors.initials: TC
authors.lastname: Prickett
authors.forename: D N
authors.initials: DN
authors.lastname: Hart
mesh_terms: D000906:Antibodies / Q000494:pharmacology*; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D016827:CD8 Antigens; D002450:Cell Communication; D003713:Dendritic Cells / Q000276:immunology*; D006801:Humans; D008213:Lymphocyte Activation / Q000276:immunology*; D007959:Lymphocyte Culture Test, Mixed; D008562:Membrane Glycoproteins / Q000276:immunology; D015375:Receptors, Interleukin-2 / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000906:Antibodies; D000945:Antigens, Differentiation, T-Lymphocyte; D016827:CD8 Antigens; D008562:Membrane Glycoproteins; D015375:Receptors, Interleukin-2