Abstract: Objective To investigate UV-or heat-inactivated Epstein-Barr virus(EBV)stimulating the production of anti-keratin autoantibody(AK auto Ab)in cultured human umbilical cord blood B cells. Methods Mononuclear cells were isolated routinely from umbilical cord blood, in which monocytes, NK cells and cytotoxicity T cells were eliminated by L-leucine methyl ester method, and T cells were removed by sheep red blood cells(SRBCs)treated with 2-amino ethyl-isothiouronium bromide (AET). The purified B cells were treated with UV-or heat-inactivated EBV respectively and then cultured in complete IMDM. CD5, CD3, CD4 and CD8 cells were detected by flow cytometry. IgG and IgM of AK auto Ab were measured by ELISA in the supernatant which came from the B cells treated by UV-inactivated EBV or EBV-transformed B cells respectively. Results In UV-inactivated EBV group CD5⁺B cells accounted for 43% and 47% of all cells detected on the 14th and 28th day, respectively. No CD3, CD4 and CD8 cells were detected during this period. In UV-inactivated EBV group the AK auto Ab of IgG and IgM increased significantly on the 18th and 26th day, respectively (P<0.05, P<0.05), but no significant difference in heat-inactivated EBV group (P>0.05). On the 40th day the AK auto Ab of IgG and IgM were significantly higher in EBV-transformed B cell group than those in UV-inactivated EBV group. Conclusions UV-inactivated EBV is able to induce AK auto Ab production but heat-inactivated EBV does not, which suggests that EBV protein might be the effective agent in inducing the production of AK auto Ab.

Key words: Keratin, Autoantibodies, Herpesvirus 4, human, B-lymphocytes