Expression and functional analysis of murine B7 delineated by a novel monoclonal antibody.
The B cell surface molecule designated B7 has been shown to be expressed by activated human B cells and monocytes and to be a ligand for the CD28 and CTLA-4 molecules on T cells. B7/CD28 interactions can provide a second signal to T cells (in addition to occupancy of the T cell antigen receptor) that is needed for T cell activation. COS cells transfected with the mouse homologue of B7 have been demonstrated to provide a stimulatory signal to murine and human T cells. In this report we describe a rat anti-mouse B7 mAb designated 1G10. Scatchard and/or FACS analyses utilizing 1G10 demonstrated that B7 was not expressed on resting splenic T cells or B cells, but could be induced at high levels on B cells cocultured with a syngeneic I-Ak-restricted autoreactive T cell hybridoma. Furthermore, activation of B cells with dibutyryl-cAMP (db-cAMP), a second messenger for class II MHC signaling, or with LPS induced the expression of B7 and the two agents showed additive effects. In contrast to B cells, freshly isolated mouse peritoneal macrophages constitutively expressed B7. Antibody-blocking experiments indicated that anti-B7 antibody partially inhibited T cell proliferative responses to primary antigenic stimulation but had no effect on the responses of previously activated T cells to antigenic restimulation.
Powers
G D
GD
Roche Research Center, Nutley, New Jersey 07110.
Faherty
D A
DA
Connaughton
S E
SE
Biondi
D A
DA
Godfrey
D I
DI
Gault
A
A
Chen
C Y
CY
Nabavi
N
N
D000818:Animals; D000911:Antibodies, Monoclonal; D000938:Antigen-Presenting Cells / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology; D018122:B7-1 Antigen / Q000276:immunology / Q000378:metabolism*; D001667:Binding, Competitive; D003994:Bucladesine / Q000494:pharmacology; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D007962:Leukocytes / Q000187:drug effects / Q000276:immunology; D008213:Lymphocyte Activation; D008211:Lymphocyte Cooperation / Q000276:immunology; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D051381:Rats; D015290:Second Messenger Systems / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology
D000911:Antibodies, Monoclonal; D018122:B7-1 Antigen; D003994:Bucladesine