Different B cell populations mediate early and late memory during an endogenous immune response

KA Pape, JJ Taylor, RW Maul, PJ Gearhart, MK Jenkins - Science, 2011 - science.org
KA Pape, JJ Taylor, RW Maul, PJ Gearhart, MK Jenkins
Science, 2011science.org
Memory B cells formed in response to microbial antigens provide immunity to later
infections; however, the inability to detect rare endogenous antigen-specific cells limits
current understanding of this process. Using an antigen-based technique to enrich these
cells, we found that immunization with a model protein generated B memory cells that
expressed isotype-switched immunoglobulins (swIg) or retained IgM. The more numerous
IgM+ cells were longer lived than the swIg+ cells. However, swIg+ memory cells dominated …
Memory B cells formed in response to microbial antigens provide immunity to later infections; however, the inability to detect rare endogenous antigen-specific cells limits current understanding of this process. Using an antigen-based technique to enrich these cells, we found that immunization with a model protein generated B memory cells that expressed isotype-switched immunoglobulins (swIg) or retained IgM. The more numerous IgM+ cells were longer lived than the swIg+ cells. However, swIg+ memory cells dominated the secondary response because of the capacity to become activated in the presence of neutralizing serum immunoglobulin. Thus, we propose that memory relies on swIg+ cells until they disappear and serum immunoglobulin falls to a low level, in which case memory resides with durable IgM+ reserves.
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