IL-2 signaling and IL-2R/IL-15Rβ expression abnormalities in T↓B+NK− SCID.

(A) Flow cytometric analysis of PBMCs for cell surface expression of γc. Equivalent amounts of γc expression are seen in both a control sample and sample from P1. (B) Tyrosine phosphorylation of JAK-3 after IL-2 stimulation. PBMCs from a control and P1 were stimulated with IL-2, lysed, and immunoprecipitated using an anti–JAK-3 antibody. JAK-3 immunoprecipitates were then immunoblotted using an antiphosphotyrosine antibody. Normal JAK-3 tyrosine phosphorylation is seen in the control sample, but only minimal tyrosine phosphorylation is seen in P1 (top panel). The filter was stripped and reblotted with an anti–JAK-3 antibody, and the blot shows equivalent amounts of JAK-3 expression in both samples (bottom panel). (C) Flow cytometric and Western blot analysis of IL-2R/IL-15Rβ expression. PBMCs from a control and P1 were analyzed by flow cytometry for cell surface expression of IL-2R/IL-15Rβ. Normal expression is seen in a control sample, but significantly decreased expression is seen in the sample from P1. Western blot analyses of whole cell lysates from a control and P1 also show decreased expression of IL-2R/IL-15Rβ. Stripping the filter and reblotting with an anti–β-actin antibody shows equivalent protein loading in each lane. (D) Northern blot analysis ofIL-2R/IL-15Rβ expression. mRNA prepared from PBMCs from a control subject and from P1. Northern blot analysis using anIL-2R/IL-15Rβ cDNA probe shows 7% of control IL-2R/IL-15Rβ expression in the sample from P1. Equivalent mRNA loading was demonstrated after stripping and reblotting the filter with a probe for β-actin.