Normal human immunoglobulins for intravenous use (IVIg) delay hyperacute xenograft rejection through F(ab′)2-mediated anti-complement activity.

Xenotransplantation between discordant species leads to a hyperacute rejection mediated by natural antibodies. both of the IgG and IgM isotypes, activation of complement and endothelial cell activation. The combination of these mechanisms leads to a transplant survival of minutes to a few hours. Polyclonal human irnmunoglobulins for intravenous use ([V]g) from normal donors have proved effective in a number of antibody-mediated disorders, as well as in inflammatory disorders. We demonstrate that administration of [V]g in a guinea pig to rat model of cardiac xenografting can effectively delay hyperacute rejection. This effect is mediated by the F(ab')₂ fragments of [V]g. and is correlated to an anti-complementary activity. [ABSTRACT FROM AUTHOR]