Antibody-dependent enhancement of coxsackievirus B3 infection of primary [CD19.sup.+] B lymphocytes

Coxsackievirus B3 (CVB3) is associated with several different acute and chronic forms of human disease, including myocarditis, aseptic meningitis, and pancreatitis. Moreover, CVB3 also infects immune cells like [CD19.sup.+] B lymphocytes, but the viral uptake mechanism into these cells is not well understood. Therefore, primary murine and human [CD19.sup.+] B cells were isolated by magnetic-activated cell separation technology and analyzed for virus receptor expression, antibody-dependent enhancement of viral infection, and different cellular surface proteins, that might be involved in mechanisms of viral uptake. Western blot analysis of these cells revealed no significant expression of the coxsackievirus-adenovirus receptor CAR. But incubation of CVB3 with serum dilutions, which exhibited binding but not neutralizing characteristics, increased viral uptake and replication significantly in a dose-dependent manner. Viral entry was reduced when Fc portions of immunoglobulins were blocked by protein A treatment. Moreover, the classical complement system rather than Fc-γ-receptor-mediated mechanisms could be involved in viral uptake. Taken together, these data suggest an antibody-dependent enhancement of CVB3 infection of primary murine and human [CD19.sup.+] B cells.