IVIg prevents the in vitro activation of T cells by neutralizing the T cell activators

► IVIg inhibits the functions of T cells activated with anti-CD3/CD28 microbeads. ► The mechanism of this inhibition was studied. ► IVIg reduces bead-to-cell binding therefore preventing T cell activation. ► IVIg does not affect CD3 and CD28 expression on T cells. ► Activated T cells are not a direct target of IVIg.