TAP, a novel T cell-activating protein involved in the stimulation of MHC-restricted T lymphocytes.
Five mAbs have been generated and used to characterize TAP (T cell activating protein) a novel, functional murine T cell membrane antigen. The TAP molecule is a 12-kD protein that is synthesized by T cells. By antibody crossblocking, it appears to be closely associated with a 16-kD protein on the T cell membrane also identified with a novel mAb. These molecules are clearly distinct from the major well-characterized murine T cell antigens previously described. Antibody binding to TAP can result in the activation of MHC-restricted, antigen-specific inducer T cell hybridomas that is equivalent in magnitude to maximal antigen or lectin stimulation. This is a direct effect of soluble antibody and does not require accessory cells or other factors. The activating anti-TAP mAbs are also mitogenic for normal heterogeneous T lymphocytes in the presence of accessory cells or IL-1. In addition, these antibodies are observed to modulate specific immune stimulation. Thus, the activating anti-TAP mAbs synergise with antigen-specific stimulation of T cells, while a nonactivating anti-TAP mAb inhibits antigen driven activation. These observations suggest that the TAP molecule may participate in physiologic T cell activation. The possible relationship of TAP to known physiologic triggering structures, the T3-T cell receptor complex, is considered. TAP is expressed on 70% of peripheral T cells and therefore defines a major T cell subset, making it perhaps the first example of a murine subset-specific activating protein.
Rock
K L
KL
Yeh
E T
ET
Gramm
C F
CF
Haber
S I
SI
Reiser
H
H
Benacerraf
B
B
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000937:Antigen-Antibody Reactions; D000938:Antigen-Presenting Cells / Q000276:immunology; D000954:Antigens, Surface / Q000032:analysis / Q000276:immunology / Q000502:physiology*; D001402:B-Lymphocytes / Q000276:immunology; D002462:Cell Membrane / Q000276:immunology; D002478:Cells, Cultured; D000939:Epitopes / Q000276:immunology; D006183:H-2 Antigens / Q000502:physiology*; D006825:Hybridomas / Q000276:immunology; D007375:Interleukin-1 / Q000494:pharmacology; D008213:Lymphocyte Activation; D051379:Mice; D008815:Mice, Inbred Strains / Q000276:immunology; D013154:Spleen / Q000276:immunology; D013601:T-Lymphocytes / Q000145:classification / Q000276:immunology*; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7
D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D000939:Epitopes; D006183:H-2 Antigens; D007375:Interleukin-1; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7