Nonclassical behavior of the mouse CD1 class I-like molecule.
The mouse CD1 (mCD1) molecule is a class I-like molecule that is encoded outside of the MHC. We show here that mCD1 shares several properties with Ag-presenting class I molecules, including a requirement for beta2-microglobulin for stable cell-surface expression in T lymphocyte transfectants and thymocytes. mCD1 is also capable of binding to mouse CD8alphabeta heterodimers participating in the activation of CD8+ T cells in a manner similar to classical class I molecules. However, mCD1 surface expression is not decreased at high temperatures in cells that lack the transporter associated with Ag processing (TAP), including both RMA-S and Drosophila melanogaster cells. The data indicate that mCD1 does not require TAP to be expressed in a stable fashion at the cell surface. We speculate that the ability of mCD1 to reach the cell surface in transporter-deficient cells may reflect its ability to present a distinct set of ligands. The properties of mCD1 described here can account, in part, for the selection of the diverse populations of T cells that are known to be mCD1 reactive.
Teitell
M
M
Department of Microbiology and Immunology, University of California at Los Angeles 90095, USA.
Holcombe
H R
HR
Brossay
L
L
Hagenbaugh
A
A
Jackson
M J
MJ
Pond
L
L
Balk
S P
SP
Terhorst
C
C
Peterson
P A
PA
Kronenberg
M
M
D000071450:ATP Binding Cassette Transporter, Subfamily B, Member 3; D018528:ATP-Binding Cassette Transporters / Q000235:genetics; D000818:Animals; D018949:Antigens, CD1 / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D016827:CD8 Antigens / Q000378:metabolism; D004331:Drosophila melanogaster / Q000235:genetics; D015395:Histocompatibility Antigens Class I / Q000276:immunology*; D016399:Lymphoma, T-Cell; D051379:Mice; D011485:Protein Binding / Q000276:immunology; D013601:T-Lymphocytes / Q000378:metabolism; D013950:Thymus Gland / Q000166:cytology / Q000378:metabolism; D014162:Transfection / Q000276:immunology; D014407:Tumor Cells, Cultured; D001613:beta 2-Microglobulin / Q000096:biosynthesis
D000071450:ATP Binding Cassette Transporter, Subfamily B, Member 3; D018528:ATP-Binding Cassette Transporters; D018949:Antigens, CD1; D016827:CD8 Antigens; D015395:Histocompatibility Antigens Class I; C489516:Tap2 protein, mouse; D001613:beta 2-Microglobulin