RESUMEN
TGF-beta family cytokines play multiple roles in immune responses. TGF-beta1-null mice suffer from multi-organ infiltration that leads to their premature death. T cells play a central role in the TGF-beta1 phenotype, as deficiency of TGF-beta1 only in T cells reproduces the lethal phenotype. Although it is known that TGF-beta1 controls B cells isotype switch and homeostasis, the source responsible for this control has not been characterized. Because of the major role that T cells play in regulating B cell responses, we addressed the T cell dependency of the TGF-beta1 control of B cells. The analysis of T cell-deficient, TGF-beta1 knockout mice and the production of chimeras in which B but not T cells lacked TGF-beta1 allowed us to show that B cells are controlled in part by cell autonomous production of TGF-beta1.