A 150-KDA MOLECULE OF MACROPHAGE MEMBRANE STIMULATES INTERLEUKIN-2 AND INTERFERON-GAMMA PRODUCTION AND PROLIFERATION OF OVALBUMIN-SPECIFIC CD4-CELLS( T)

In the present study, we describe the potential co-stimulatory role of a macrophage membrane-associated protein of 150 kDa (M150). The prote in was isolated by sodium dodecyl sulfate-polyacrylamide gel electroph oresis and was found to be a single molecule on two-dimensional gel el ectrophoresis. The molecule was re-constituted in phosphatidyl choline vesicles and tested for its ability to promote the proliferation and the secretion of lymphokines from T helper (Th) cells. The reconstitut ed M150 induced a significant proliferation of anti-CD3 monoclonal ant ibody (mAb)-stimulated ovalbumin-specific CD4(+) T cells. Further, Th cells activated with this molecule in the presence of anti-CD3 mAb mai nly secreted interleukin (IL)-2 and interferon-gamma but not IL-4. M15 0 could not promote the proliferation of Th cells, or lymphokine secre tion in the absence of anti-CD3 mAb. These observations suggest that M 150 acts by selectively activating a Th1-like immune response.