A modified IgG antibody binds and neutralizes TGFβ1 selectively and with high affinity and avidity. The modified IgG antibody comprises four polypeptide chains and may comprise modifications to the elbow regions of the polypeptide chains. The modified IgG antibody may comprise the same VH and VL domains or CDR regions as metelimumab. The modified IgG antibody is useful in therapeutic and diagnostic applications.