A human suppressor T-cell factor that inhibits T-cell replication by interaction with the IgM-Fc receptor (CD7)

Mohamed Emara, William M. Baldwin, Olivera J. Finn, Fred Sanfilippo

Research output: Contribution to journalArticle

Abstract

We have previously described the induction of human suppessor T cells from fresh peripheral blood lymphocytes of a kidney transplant recipient by in vitro stimulation with an autologous irradiated antidonor CTL line (EE-1) grown from a biopsy of the patient's own renal allograft. The induced T cells (designated TsEE) were shown to inhibit the in vitro generation of proliferative and cytotoxic responses of autologous T cells and nonautologous T cells that shared HLA-B7 with TsEE cells. Stimulation of TsEE cells by the autologous irradiated inducer line (EE-1) produced soluble factors (designated TsEEF) that similarly inhibited autologous and nonautologous T-cell responses to alloantigens and mitogens, but in a non-HLA-restricted manner. In this study, we examined the functional interaction of TsEEF with various cells surface receptors. TsEEF specifically inhibited the proliferation of stimulated and transformed T cells expressing CD7, a putative receptor for IgM-Fc (FcRμ). Blocking or capping of CD7-FcRμ determinants on responder T cells by pretreatment with IgM or anti-CD7 monoclonal antibodies (3A1, HuLy-m2) abrogated TsEEF activity. Conversely, pretreatment of T cells with TsEEF significantly reduced their binding of IgM and HuLy-m2. TsEEF was demonstrated not to be IgM or IgG, and its activity was not removed by preabsorption with IgM or IgG; however, its activity could be competitively inhibited by coculture with IgM. By cocapping experiments and studies utilizing CD7- (Hut-78) and CD7+ (HSB, Molt-4) T-cell lines, TsEEF activity did not appear to involve interactions with other T-cell or non-T-cell surface receptors. These findings suggest a novel role for FcRμ-CD7 T-cell surface receptors in binding certain soluble T-cell factors that result in the inhibition of T-cell replication.

Original languageEnglish (US)
Pages (from-to)87-102
Number of pages16
JournalHuman Immunology
Volume25
Issue number2
DOIs
StatePublished - 1989
Externally publishedYes

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ASJC Scopus subject areas

  • Immunology
  • Immunology and Allergy

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