CROSS-TALK BETWEEN T-CELL AND B-CELL GENERATES B-ANTIGEN-PRESENTING CELLS ABLE TO INDUCE INOSITOL PHOSPHATE PRODUCTION IN T-CELL RESPONDINGTO MLS(A) SUPERANTIGENS
Am. Orourke et Sr. Webb, CROSS-TALK BETWEEN T-CELL AND B-CELL GENERATES B-ANTIGEN-PRESENTING CELLS ABLE TO INDUCE INOSITOL PHOSPHATE PRODUCTION IN T-CELL RESPONDINGTO MLS(A) SUPERANTIGENS, European Journal of Immunology, 27(12), 1997, pp. 3253-3258
Previous studies showed that activation of CD4(+) T cells with mouse m
ammary tumor virus-encoded Mls(a) superantigens induces strong prolife
rative responses and interleukin-2 production but fails to elicit typi
cal early T cell receptor (TCR)-mediated signal transduction events, s
uch as hydrolysis of polyphosphoinositides (PI) or an increase in intr
acellular calcium. Here we show that the failure of Mls(a) antigen to
activate PI hydrolysis applies when resting B cells are used as antige
n-presenting cells (APC). By contrast, when Mls(a)-bearing B cells are
activated for 24h by exposure to lipopolysaccharide or, more importan
tly, to Mls(a)-reactive T cells or anti-CD40 antibodies the cells deve
lop the capacity to elicit easily detectable PI turnover. These studie
s demonstrate that, for B cells as APC, the initiation of certain TCR-
associated signal transduction pathways can depend on activation of th
e APC. The data suggest that cross talk between T cells and resting B
cells can suffice to generate competent B APC and lead to the delayed
initiation of signaling pathways important in T cell responses.