A. Brunmark et Am. Orourke, AUGMENTATION OF MATURE CD4(-CELL RESPONSES TO ISOLATED ANTIGENIC CLASS-II PROTEINS BY FIBRONECTIN AND INTERCELLULAR-ADHESION MOLECULE-1() T), The Journal of immunology, 159(4), 1997, pp. 1676-1685
Mature CD4(+) T cells can undergo stable adhesion to isolated antigeni
c MHC complexes, and upon TCR engagement exhibit up-regulated adhesion
to the integrin ligands fibronectin (FN) and intercellular adhesion m
olecule-1 (ICAM-1), Here, we have examined T cell responses to purifie
d antigenic class II complexes, alone or coimmobilized in the presence
of FN or ICAM-1, T cell adhesion to immobilized peptide-MHC complexes
alone stimulated suboptimal, but marked levels of IFN-gamma and IL-2
secretion, and this was accompanied by cell proliferation, T cell adhe
sion to both FN and ICAM-1 strongly augmented cytokine release and T c
ell proliferation, Activation of V beta 3(+) and V beta 8(+) T cell li
nes by isolated staphylococcal enterotoxin-MHC complexes was also exam
ined, and surprisingly, a V beta 8(+) T cell line displayed significan
t cell adhesion or later response to staphylococcal enterotoxin B-MHC
complexes only when Ag was coimmobilized with ICAM-1 or FN, The result
s demonstrate that adhesion of CD4(+) T cells to ICAM-1 or FN activate
d by natural TCR ligands can strongly augment T cell signaling and dow
nstream responses, Moreover, for some Ags, T cell interaction with acc
essory ligands may be critical in attaining a threshold level of recep
tor occupancy for cell activation.