Differential T-cell activation by B7-1 expression.
T-cell receptor-mediated T-cell activation requires cosimulation signal, which can be provided by B7-1 molecule. Our previous study demonstrated that the coexpression of a covalent peptide/major histocompatibility complex class II molecule complex and costimulatory molecule B7-1 by recombinant adenovirus leads to synergy in peptide-specific T-cell activation. However, the viral antigen-specific T-cell activation is not enhanced by B7-1 expressed by the adenovirus. To verify the differential T cell activation by B7-1 and investigate its underlying mechanisms, we constructed an adenovirus coexpressing a covalent complex of hen egg lysozyme peptide/I-Ak (HEL46-61/I-Ak) and B7-1 in the present study. In vivo studies revealed that HEL46-61-specific T-cell response, but not viral antigen-specific T-cell response, was enhanced by B7-1 expression mediated by the adenovirus, suggesting that exogenous B7-1 expression may regulate T-cell response to these two different antigens through distinct mechanisms. Furthermore, our results revealed that antigen-presenting cells were not susceptible to adenovirus infection in vivo. Based on these findings, the possible mechanism of differential B7-1 costimulation on peptide-specific and viral antigen-specific T-cell activation is discussed.
Li
Wei
W
Department of Ophthalmology, University of Miami School of Medicine, FL, USA. wli@med.miami.edu
Rosenzweig
Anthony
A
Huber
Brigitte T
BT
D000256:Adenoviridae / Q000235:genetics / Q000276:immunology; D000257:Adenoviridae Infections / Q000276:immunology; D000595:Amino Acid Sequence; D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology / Q000821:virology; D000956:Antigens, Viral / Q000276:immunology; D018122:B7-1 Antigen / Q000276:immunology*; D015152:Blotting, Northern; D002478:Cells, Cultured; D018014:Gene Transfer Techniques; D008213:Lymphocyte Activation / Q000276:immunology*; D017737:Macrophages, Peritoneal / Q000276:immunology / Q000821:virology; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D009113:Muramidase / Q000276:immunology; D010446:Peptide Fragments / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*
D000956:Antigens, Viral; D018122:B7-1 Antigen; D010446:Peptide Fragments; C066759:hen egg lysozyme peptide (46-61); D009113:Muramidase