Differential effect on TCR: CD3 stimulation of a 90-kD glycoprotein (gp90/Mac-2BP), a member of the scavenger receptor cysteine-rich domain protein family

B. Silvestri, F. Calderazzo, V. Coppola, A. Rosato, S. Iacobelli, C. Natoli, A. Ullrich, I. Sures, M. Azam, C. Brakebush, L. Chieco-Bianchi, A. Amadori

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We studied the effects of a 90-kD glycoprotein (gp90/Mac-2BP) belonging to the scavenger receptor family, present in normal serum and at increased levels in inflammatory disease and cancer patients, on some T cell function parameters. Whereas the lymphocyte proliferative response to non-specific mitogens such as phytohaemagglutinin (PHA) and concanavalin A (Con A), but not pokeweed mitogen (PWM), was strongly reduced, probably due to the lectin- binding properties of gp90/Mac-2BP, the response to T cell receptor (TCR) agonists such as superantigens and allogeneic cells was potentiated. When lymphocytes were stimulated with different anti-TCR:CD3 MoAbs, both in soluble and solid-phase form, gp90/Mac-2BP was able to down-regulate the proliferative response to anti-CD3 MoAb, whereas the response to anti-TCR αβ MoAb was enhanced. A similar differential effect was observed when a MoAb against CD5 (another member of the scavenger receptor superfamily) was added to anti-CD3 or anti-TCR-stimulated cells; anti-CD5 MoAb strongly down- modulated the CD3-mediated response, whereas its presence in culture was associated with potentiation of the response to TCR αβ agonists. gp90/Mac- 2BP was able per se to up-regulate Ca2+ levels in freshly isolated lymphocytes; moreover, its presence in culture was associated with increased Ca2+ mobilization following stimulation with anti-TCR αβ, but not anti- CD3 MoAb. These data indicate that gp90/Mac-2BP could be able to influence some immune responses, possibly through multiple homologous interactions with other members of the scavenger receptor family; moreover, our findings suggest that signalling through the different components of the TCR:CD3 complex may follow distinct activation pathways into the cells.

Original languageEnglish
Pages (from-to)394-400
Number of pages7
JournalClinical and Experimental Immunology
Issue number3
Publication statusPublished - 1998


  • CD3
  • gp90/Mac-2BP
  • Scavenger receptor
  • T lymphocytes
  • TCR

ASJC Scopus subject areas

  • Immunology


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