title: Cytofluorometric analyses of human T cell CD2/CD4 inter-molecular interactions.
abstract: Incubation of human T lymphocytes with saturating concentrations of combinations of certain anti-CD2 and -CD4 mAb results in reciprocal down-regulation of the cell surface density expression of the respective CD molecules. Such reciprocal down-regulation occurs at 0 degrees C in the presence of sodium azide and appears selective for CD2 and CD4 molecules because mAb identifying various other CD T cell surface molecules (anti-Leu2a, -OK-CLL, -W6/32, -beta 2-microglobulin, -4B4) do not modulate CD2 or CD4 R density, and because anti-CD2 mAb (anti-OKT11 and -D66 clone-1) do not alter CD8 R density (anti-OKT8, -Leu2a) and vice versa. Down-regulation of CD2 by mAb specific to CD4 is epitope-specific but does not vary on the basis of the antibody isotype used. The anti-CD4 mAb, Leu3a, was the strongest CD2 down-regulator examined followed by OKT4F. mAb specific to other CD4 epitopes (B, C, D, and E) caused only slight down-regulation of CD2 expression whereas anti-OKT4 and -OKT4A mAb had no significant regulatory effect. Also, mAb specific to the 9.6 (anti-OKT11) and D66 (anti-D66 clone 1) epitopes of the CD2 molecule down-regulated CD4 density detectable with Leu3a, OKT4, and OKT4A anti-CD4 mAb. Down-regulation of CD2 by anti-CD4 mAb also occurred with the transformed T cell line, KE-37, which demonstrates that such effects can occur without mononuclear phagocytic accessory cells. From these data it can be concluded that important T cell immunoregulatory signals may be transmitted intramembranally between CD2 and CD4 glycoproteins.
authors.affiliation: Department of Pathology, Emory University, School of Medicine, Atlanta, GA 30322.
authors.forename: C E
authors.initials: CE
authors.lastname: Bueso-Ramos
authors.forename: R M
authors.initials: RM
authors.lastname: Donahoe
authors.forename: J K
authors.initials: JK
authors.lastname: Nicholson
authors.forename: J J
authors.initials: JJ
authors.lastname: Madden
authors.forename: A
authors.initials: A
authors.lastname: Falek
mesh_terms: D000328:Adult; D000911:Antibodies, Monoclonal / Q000502:physiology*; D000937:Antigen-Antibody Reactions; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis*; D005434:Flow Cytometry; D006801:Humans; D013601:T-Lymphocytes / Q000032:analysis / Q000145:classification*; D013602:T-Lymphocytes, Cytotoxic / Q000032:analysis; D006377:T-Lymphocytes, Helper-Inducer / Q000032:analysis; D050378:T-Lymphocytes, Regulatory / Q000032:analysis
chemical_list: D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte