[HTML][HTML] B-1a and B-1b cells exhibit distinct developmental requirements and have unique functional roles in innate and adaptive immunity to S. pneumoniae

KM Haas, JC Poe, DA Steeber, TF Tedder - Immunity, 2005 - cell.com
KM Haas, JC Poe, DA Steeber, TF Tedder
Immunity, 2005cell.com
Summary B-1a and B-1b lymphocytes were found to exhibit specialized roles in providing
immunity to Streptococcus pneumoniae and differ dramatically in their developmental
requirements. Transgenic mice overexpressing CD19 (hCD19Tg) generated B-1a cells and
natural antibodies that provided protection during infection, while CD19-deficient (CD19−/−)
mice lacked B-1a cells, lacked natural antibodies, and were more susceptible to infection. By
contrast, pneumococcal polysaccharide (PPS) immunization protected CD19−/− mice during …
Summary
B-1a and B-1b lymphocytes were found to exhibit specialized roles in providing immunity to Streptococcus pneumoniae and differ dramatically in their developmental requirements. Transgenic mice overexpressing CD19 (hCD19Tg) generated B-1a cells and natural antibodies that provided protection during infection, while CD19-deficient (CD19−/−) mice lacked B-1a cells, lacked natural antibodies, and were more susceptible to infection. By contrast, pneumococcal polysaccharide (PPS) immunization protected CD19−/− mice during lethal challenge, whereas hCD19Tg mice remained unprotected. This resulted from differences in the B-1b subset: the key population found to produce protective PPS-specific antibody in both wild-type and CD19−/− mice. Thus, CD19−/− mice generated B-1b cells and protective adaptive PPS-specific antibody responses, whereas hCD19Tg mice lacked B-1b cells and adaptive PPS-specific antibody responses. This reciprocal contribution of B-1a and B-1b subsets to innate and acquired immunity reveals an unexpected division of labor within the B-1 compartment that is normally balanced by their coordinated development.
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