Abstract 250: Four-And-A-Half LIM Domain Protein 2 Plays a Critical Role in Spleen T-Cell Dependent Antibody Response

Background: Four-and-a-half LIM domain protein 2 (FHL2) is an adaptor molecule that regulates signalling cascades and gene transcription. We have uncovered vasculoprotective and atheroprotective effects of FHL2 knockout in mice. Since B cells could regulate these processes, we investigated the potential role of FHL2 in B cell function and activity. Methods and Results: Under basal conditions, FHL2-/- mice presented a mild splenomegaly (84.0±9.0 vs 68.0±5.0mg), associated with bigger spleen follicles (1.6 fold) and higher proportions of spleen B cells (56.0±2.0 vs 40.0±9.0%) vs WT mice. Flow cytometry confirmed significantly higher (p<0.05) proportions of B cells in the follicles (Fo)(CD23+CD21lo/int) (77.0±1.0 vs 67.0±3.0%) and the marginal zone (Mz)(CD23-,CD21+)(7.0±1.0 vs 2.5±1.0%) of FHL2-/- vs WT mice. Mice were injected with sheep red blood cells (SRBC) to elicit a T cell-dependent B cell activation. SRBC did not influence Fo and Mz B cell numbers, but it did affect germinal center (GC) formation. GC...