Affiliations: Preclinical Biology Research, Bayer Corp., 800 Dwight Way, Berkeley, CA, USA
Correspondence:
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Correspondence and reprint requests to: Gayle Delmonte Wetzel, Preclinical Biology Research, Bayer Corp., 800 Dwight Way, Berkeley, CA 94701, USA.
Abstract: For human B lymphocytes, Epstein-Barr virus (EBV) is a polyclonal activator, inducing both proliferation and Ig secretion. It is also a transforming virus capable of generating immortalized B cell lines. These early and late functions of EBV are not apparently connected. The receptor for EBV CD21, also serves as a receptor for some complement components and is called CR2. This molecule associates with CD19 and TAPA-1 on the surface of B cells. This complex is involved in signaling B cells and participates in many responses. We have observed that simultaneous ligation of CD40 and the CD21 complex, by exposure to anti-CD40 MAbs and EBV enhances both the short-term proliferation as well as the long-term transformation rate of human B lymphocytes. B cell proliferation shows synergy between anti-CD40 MAb and EBV CD19 also appears to be involved in the synergistic activation of B cells through CD40 and CD21, since ligation of CD19 with anti-CD19 MAbs, either prior to or concomitant with exposure to anti-CD40 and EBV markedly inhibits both proliferation and subsequent B cell transformation. These observations do not elucidate the mechanisms of B cell transformation employed by EBV but they do suggest a relationship between early proliferation and later transformation induced by the virus. Anti-CD40 enhances both these effects and anti-CD19 is capable of inhibiting both.
Keywords: EBY, CD40, transformation, human B-lymphocytes
