Direct ex vivo evaluation of long-lived protective antiviral memory B cell responses against hepatitis B virus

Abstract

Background. The frequency of protective antiviral memory B cells after hepatitis B virus (HBV) vaccination is unknown. Methods. A novel 2-step immunomagnetic protocol to assess the ex vivo frequency of protective HBV surface antigen (HBsAg)-specific memory B cells was used. Results. HBsAg-specific memory B cells were detected in vaccinated individuals, although at very low frequency (median, 0.2% of CD19+ cells [range, 0%-4% of CD19+ cells]). No correlation existed between the frequency of HBsAg-specific memory B cells and the corresponding serum antibody titer or B cell enzyme-linked immunosorbent spot findings. Conclusion. Our results indicate sustained B cell-mediated protection against HBV despite waning antibody titers, which is consistent with clinical observations. © 2008 by the Infectious Diseases Society of America. All rights reserved.