Synergy between anti-CD40 MAb and Epstein-Barr virus in activation and transformation of human B lymphocytes.
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 the 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.
Tsuchiyama
L
L
Preclinical Biology Research, Bayer Corp., Berkeley, CA 94701, USA.
Kieran
J
J
Boyle
P
P
Wetzel
G D
GD
D000911:Antibodies, Monoclonal / Q000276:immunology*; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology*; D019013:CD40 Antigens / Q000276:immunology*; D002455:Cell Division / Q000276:immunology; D002472:Cell Transformation, Viral; D002474:Cell-Free System; D002478:Cells, Cultured; D004854:Herpesvirus 4, Human / Q000502:physiology*; D006801:Humans; D008213:Lymphocyte Activation / Q000276:immunology / Q000502:physiology*; D013154:Spleen / Q000166:cytology
D000911:Antibodies, Monoclonal; D019013:CD40 Antigens