THE B-CELL RESPONSE IN LYMPHOID-TISSUE OF MICE IMMUNIZED WITH VARIOUSANTIGENIC FORMS OF THE INFLUENZA-VIRUS HEMAGGLUTININ

Protection of BALB/c (H-2(d)) mice against secondary challenge with in fluenza A viruses is primarily dependent on appropriate recognition of the hemagglutinin (HA) molecule by effectors of humoral immunity, the B lymphocytes and their product the immunoglobulin molecules. The inf luence of the antigenic form of the HA in eliciting protective antibod ies is not clearly defined, We directly monitored the kinetics, charac ter, localization, and helper T-cell dependence of the primary antibod y-forming cell (AFC) response and the development of B-cell memory in lymphoid tissues associated with the upper and lower respiratory tract s, and in the spleen and bone marrow, to three forms of HA with variou s degrees of antigenic organization, Our results show that the antigen ic organization of HA substantially influences B-cen immunity, namely, the capacity to generate both primary AFCs and memory B cells respons ive to lethal challenge. Immunization by infection is the most efficie nt means of generating protective memory B cells, in contrast to subun it vaccine. The data also indicate that memory AFCs are predominantly localized to the regional lymphoid tissue where challenge HA is found, unlike primary AFCs, which are restricted to the priming site and whi ch require in vivo CD4(+) T-cell help.