Xid-like immunodeficiency in mice with disruption of the p85 alpha subunitof phosphoinositide 3-kinase

Mice with a targeted gene disruption of p85 alpha, a regulatory subunit of phosphoinositide 3-kinase, had impaired B cell development at the pro-B cel l stage, reduced numbers of mature B cells and peritoneal CD5(+) Ly-1 B cel ls, reduced B cell proliferative responses, and no T cell-independent antib ody production. These phenotypes are nearly identical to those of Btk(-/-) or rid (X-Linked immunodeficiency) mice. These results provide evidence tha t p85 alpha is functionally Linked to the Btk pathway in antigen receptor-m ediated signal transduction and is pivotal in B cell development and functi ons.