Intravenous immunoglobulin G-mediated inhibition of T-cell proliferation reflects an endogenous mechanism by which IgG modulates T-cell activation

Indirect inhibition of in vivo and in vitro T-cell responses by intravenous immunoglobulins due to impaired antigen presentation

“…21,22,42 We rather showed here that T cells could be efficiently activated in the presence of IVIg, using paraformaldehydefixed OVA-loaded APCs or polyclonal T-cell activation after CD3/ CD28 stimulation. These experiments led to the hypothesis that IVIg inhibited T-cell responses by decreasing the ability of APCs to present antigens in an MHC II-restricted manner.…”

“…These studies showed that IVIg inhibited T-cell proliferation or induced apoptosis. [16][17][18][19][20][21][22] However, other studies reported the absence of effect of IVIg on T cells using alternative experimental conditions, making it difficult to derive strong conclusions on the role of IVIg on T-cell activation, proliferation, and survival. 16,[23][24][25] One possible explanation for the discrepant results could be that ex vivo allogeneic or polyclonal activation of purified cells by lectins, mitogens, or anti-CD3 antibodies is different from the physiologic context, leading to in vivo T-cell activation in response to an (auto)antigen.…”

Neutralization of mitogenic lectins by intravenous immunoglobulin (IVIg) prevents T cell activation: does IVIg really have a direct effect on T cells?

“…These lectins have been used in numerous studies to determine the effect of IVIg on lymphocyte functions, leading to the conclusion that IVIg had a direct effect on activated T or B cells (inhibition of proliferation, cytokine secretion, expression of activation markers such as CD25 or CD69, or immunoglobulin secretion) [22][23][24][25][26][27][28][29]. In the light of the results presented here, we believe that these conclusions should be revisited.…”

Use of immunoglobulins in the prevention of GvHD in a xenogeneic NOD/SCID/γc− mouse model

“…As inhibition of T-cell proliferation is one of the caveats of immunosuppression because it leads to the inhibition of the graft vs leukemia, this finding could have an impact on clinical practice. Many studies showed that IVIG inhibit T-cell proliferation or induce apoptosis 42,43,[53][54][55][56][57] whereas others failed to demonstrate any direct effect of IVIG on T-cells. 58,59 Interestingly, studies showing an inhibition of T-cell proliferation or an induction of apoptosis were performed in vitro whereas studies that failed to demonstrate any direct effect on T-cell proliferation were performed in vivo.…”