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Monocyte‐Dependent Costimulatory Effect of TGF‐β1 on Rat T‐Cell Activation
Author(s) -
SCHIÖTT Å.,
SJÖGREN H. O.,
LINDVALL M.
Publication year - 1996
Publication title -
scandinavian journal of immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.934
H-Index - 88
eISSN - 1365-3083
pISSN - 0300-9475
DOI - 10.1046/j.1365-3083.1996.d01-308.x
Subject(s) - spleen , t cell , superantigen , cd8 , tgf beta 1 , biology , cytotoxic t cell , population , transforming growth factor beta , monocyte , immunology , microbiology and biotechnology , in vitro , chemistry , transforming growth factor , immune system , medicine , biochemistry , environmental health
TGF‐β1 is known to have suppressive effects on both T‐cell proliferation and effector functions, but costimulatory effects have also been reported. In the present investigation the effect of TGF‐β1 is studied in vitro on T‐cell proliferative responses of rat spleen cells and of lymph node cells to alloantigens (MLR), the superantigen Staphylococcal enterotoxin A (SEA) or IL‐2. Without addition of TGF‐β1, adherent, freshly isolated rat spleen monocytes have a suppressive effect on T‐cell activation, which upon addition of TGF‐β1 is reversed to a strong costimulatory effect. The costimulatory effect of TGF‐β1 is shown to be entirely dependent on the presence of fresh monocytes. Costimulation is demonstrated when TGF‐β1 is added to spleen cells at the start of the in vitro assays but not when added more than 24 h after the start. Costimulation is not demonstrable when TGF‐β1 is added to lymph node cells alone but is readily detectable after admixture of freshly isolated spleen monocytes to the lymph node cells. TGF‐β1 added at the end of culture induces suppression of T‐cell activation irrespective of the presence or absence of monocytes. When TGF‐β1 is added both at the start of an MLC and again after 4 days, the costimulatory effect is maintained, although somewhat moderated. The costimulatory effect of TGF‐β1 is demonstrated as an increase of the T blast cell population of both CD4 + IL‐2R + and CD8 + IL‐2R + T‐cell subsets, whereas the suppressive effect of TGF‐β1 is shown as reduction of the same parameters.