Human T cell responses to human and porcine endothelial cells are highly sensitive to cyclosporin A and FK506 in vitro
Batten, P.; McCormack, A.M.; Page, C.S.; Yacoub, M.H.; Rose, M.L.
Transplantation 68(10): 1552-1560
1999
ISSN/ISBN: 0041-1337 PMID: 10589954 Document Number: 501736
Background. Human T cells proliferate in response to both human umbilical vein endothelial cells (HUVEC) and porcine aortic endothelial cells (PAEC) via the second signals LFA-3/CD2 and B7-2 (CD86), respectively. Previous studies have shown that stimulation of T cells via CD28 or phorbol myristate acetate (PMA) activation is highly resistant to inhibition by cyclosporine A (CsA) and tacrolimus (FK506), as is the response of T cells to phytohemmaglutinin in the presence of endothelial cells. We have investigated the inhibitory effects of CsA and FK506 on the direct response of human CD4+ T cells to HUVEC and PAEC and the effect of adding B7-1 transfectants. Methods. T cell proliferation, interleukin-2 release bioassays and a multiple cytokine bioassay employing the TF-1 cell line were used as indicators of T cell responses to HUVEC and PAEC either in the presence or absence of CsA and FK506. In some experiments, B7-1 transfectants were also added. Results. Proliferative responses and interleukin-2 release were highly sensitive to CsA, the ID50 being significantly less for HUVEC (6.5 ng/ml) than PAEC (15 ng/ml). The ID50 of CsA for the mixed lymphocyte response (MLR) was similar to PAEC (18.6 ng/ml), all these values being significantly less than the T cell activation by phytohemmaglutinin (PHA) (227 ng/ml). Addition of B7-1 transfectants significantly increased interleukin-2 production by T cells/HUVEC and resistance to CsA was greatly increased to an ID50 of >1000 ng/ml. In contrast, addition of B7-1 transfectants to T cells/PAEC had no effect either on T cell proliferation, IL-2 production, or CsA resistance. Similar results were obtained with FK506. Using the TF-1 cell line, it was determined that cytokines other than IL-2 are released during CD4+ T cell/EC interactions, with similar sensitivity to CsA and FK506. Conclusions. It is concluded that both allogeneic and xenogeneic T cell/endothelial responses should be inhibited by therapeutic levels of CsA in vivo, assuming the absence of trans-stimulation by B7 molecules.