Mutations Affecting Either Generation or Survival of Cells Influence the Pool Size of Mature B Cells

AbstractThe mature B cell compartment of MHC class II–deficient B6 I-Aα−/− and the btk-defective CBA/N mouse strain is 4- to 5-fold smaller than in wild-type B6 mice. The defect in B6 I-Aα−/− mice is intrinsic to B cells and due to a 4- to 5-fold reduced lifespan, which however can be normalized by an I-Eαd transgene, but only when expressed early during B cell development. The reduced number of mature B cells in the btk-defective CBA/N mouse is due to a 4- to 5-fold lower number of immature splenic B cells entering the mature compartment. The combined defects of reduced lifespan and impaired generation in double mutant mice result in a severe deficiency in the mature B cell pool