A comparison of the IgG and IgA responses in the plasma from healthy donors also revealed differential responses to certain EBV proteins. All 10 normal sera had IgA responses at a 1:1000 dilution to the viral IL10 BCRF1, the tegument protein BRRF2, and the latency membrane protein LMP2A. In contrast, even at a 1:100 dilution, IgG responses to BCRF1, BRRF2, or LMP2A were not detected in these plasma samples. The IgA response to vIL10 is particularly interesting because vIL10 is an immune modulator that can have an impact on localized immune escape of EBV-infected cells.