Induction of an antibody response capable of recognizing highly diverse
strains is a major obstacle to the development of vaccines for viruses such
as HIV and influenza. Here, we report the dynamics of B cell expansion and
evolution following vaccination with a replication competent Adenovirus type
4 recombinant virus expressing influenza H5 hemagglutinin. Fluorescent H1 or
H5 probes were used to quantitate and isolate peripheral blood B cells and their
antigen receptors. We observed increases in monoclonal antibody somatic
hypermutation and potency several months beyond the period of active viral
replication that was not detectable at the level of sera. Although serum
neutralization was modest, individual antibodies that were broad and potent
could be isolated including one stem-specific antibody that is part of a new
multi-donor class. These results demonstrating prolonged evolution of the B
cell response for months after vaccination should be considered in efforts to
evaluate or boost vaccine-induced immunity.

Language: Japanese