Enumeration and characterization of virus-specific B cells by multicolor flow cytometry

Abstract

To better characterize B cell responses induced to influenza virus, we developed an assay to directly quantify and characterize virus-specific B cells. We used purified and biotinylated whole virus as well as the major influenza virus surface antigen, hemagglutinin (HA) to label virus-specific B cells induced by immunization of mice with whole influenza virus in adjuvant. Immunization with adjuvant alone caused non-specific binding of whole virus to a large number of B cells in the draining lymph nodes as assessed by flow cytometry. This precluded the use of whole virus as a specific staining reagent. In contrast, staining with bromelain-cleaved purified and biotinylated influenza virus HA i..