- Regulation of T cell activation in vitro and in vivo by targeting the OX40-OX40 ligand interaction: amelioration of ongoing inflammatory bowel disease with an OX40-IgG fusion protein, but not with an OX40 ligand-IgG fusion protein. Higgins, L.M., McDonald, S.A., Whittle, N., Crockett, N., Shields, J.G., MacDonald, T.T. J. Immunol. (1999)