V. Gelfanov et al., DIFFERENTIAL REQUIREMENT OF CD28 COSTIMULATION FOR ACTIVATION OF MURINE CD8(-NODE CELLS() INTESTINAL INTRAEPITHELIAL LYMPHOCYTE SUBSETS ANDLYMPH), The Journal of immunology, 155(1), 1995, pp. 76-82
The CD8(+)CD4(-) (CD8(+)) murine small intestinal intraepithelial lymp
hocytes (IELs) contain two subpopulations, one expressing alpha alpha-
CD8 homodimers and another alpha beta-CD8 heterodimers, In this study,
plate-bound anti-TCR beta-chain (TCR-beta) mAb alone or combined with
anti-CD28 mAb is used as a model system to study activation requireme
nt of these two CD8(+) IEL subsets, In contrast to CD8(+) lymph node (
LN) cells that require both TCR and CD28 triggering for activation, al
pha beta-CD8(+) IELs proliferate and produce IL-2 and IFN-gamma when s
timulated with anti-TCR-beta mAb alone, and soluble CTLA-4 Ig has no e
ffect on their responses. On the other hand, alpha alpha-CD8(+) IELs n
either make IL-2 or IFN-gamma nor proliferate even when both stimuli a
re provided, However, alpha alpha-CD8(+) IELs are capable of prolifera
tion to a similar extent as alpha beta-CD8(+) IELs in the presence of
exogenous IL-2. The frequency of cells capable of proliferation in bot
h CD8(+) IEL subsets is lower than in CD8(+) LN cells, which contribut
es to the weaker and delayed response of CD8(+) IELs.