Human B7-1 is more efficient than B7-2 in providing co-stimulation for alloantigen-specific T cells.
Besides a signal via the T cell receptor/CD3 complex, an additional costimulatory signal is required for optimal T cell activation. This signal can be delivered by interaction of either B7-1 or B7-2 expressed by antigen-presenting cells with CD28 on the T cells. Comparison of the function of B7-1 and B7-2 in different experimental animal systems generated conflicting data on the roles for the co-stimulatory molecules. We therefore investigated whether there are differences between B7-1 and B7-2-mediated co-stimulation in an alloantigen-specific primary T cell response induced by B7-transfected human cell lines of epithelial origin. Both transfected keratinocyte cell lines efficiently induce T cell proliferation and the ratios of stimulator versus responder cells are similar. The kinetics of proliferation and interleukin (IL)-2, IL-4 and interferon-gamma production are also comparable between both transfectant lines. However, despite equal B7 expression levels, it is consistently found that the magnitude of the B7-1-induced T cell proliferation was higher than that of B7-2. Comparison of precursor frequencies of helper T lymphocytes responsive with either B7-1 or B7-2 revealed that the frequency of B7-1-responsive T cells was higher than that of B7-2, and that the frequency of cells activated by a combination of B7-1 and B7-2 did not differ significantly from that of B7-1 alone. We therefore conclude that the B7-2-responsive T cells are part of the B7-1-responsive population, and that B7-1 on keratinocytes is more efficient in providing co-stimulation for alloantigen-specific T cells.
van Dijk
A M
AM
Department of Immunohematology, University Hospital Utrecht, The Netherlands. a.m.c.vandijk@lab.azu.nl
Otten
H G
HG
Vercauteren
S M
SM
Kessler
F L
FL
de Boer
M
M
Verdonck
L F
LF
de Gast
G C
GC
D015703:Antigens, CD / Q000502:physiology*; D018122:B7-1 Antigen / Q000502:physiology*; D051940:B7-2 Antigen; D006801:Humans; D007519:Isoantigens / Q000276:immunology*; D008213:Lymphocyte Activation; D008562:Membrane Glycoproteins / Q000502:physiology*; D013601:T-Lymphocytes / Q000276:immunology*; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology
D015703:Antigens, CD; D018122:B7-1 Antigen; D051940:B7-2 Antigen; C497964:CD86 protein, human; D007519:Isoantigens; D008562:Membrane Glycoproteins