Generation of long-lived plasma cells to serogroup B Neisseria meningitidis after murine immunisation with an outer membrane protein vaccine

There is no universal vaccine against serogroup B meningococcus (Men B). We investigated the development of spleen and bone marrow-specific IgG-secreting plasma cells (ASC) in mice immunised with the Cuban outer membrane protein (OMP) vaccine (VA-MENGOC-BC®). Bone marrow was the predominant anatomical site of specific ASC and showed constant ASC levels (∼4%) at each time point analysed, indicating the production of long-lived ASC. A mean of 2.36 and 0.35% of Men B ASC was detected in spleen after the third dose and 2 months later, respectively, indicating a short-lived population. The data suggest that a short-lived ASC population in spleen was responsible for serum IgG anti-OMP while ASC from bone marrow produced persistent bactericidal antibodies against the vaccine strain. The response to the booster dose was consistent with development of memory B cells by primary vaccination.