Anti-inflammatory effects of infliximab in mice are independent of tumour necrosis factor α neutralization

Abstract

SummaryInfliximab (IFX) has been used repeatedly in mouse preclinical models with associated claims that anti‐inflammatory effects are due to inhibition of mouse tumour necrosis factor (TNF)‐α. However, the mechanism of action in mice remains unclear. In this study, the binding specificity of IFX for mouse TNF‐α was investigated ex vivo using enzyme‐linked immunosorbent assay (ELISA), flow cytometry and Western blot. Infliximab (IFX) did not bind directly to soluble or membrane‐bound mouse TNF‐α nor did it have any effect on TNF‐α‐induced nuclear factor kappa B (NF‐κB) stimulation in mouse fibroblasts. The efficacy of IFX treatment was then investigated in vivo using a TNF‐α‐independent Trichuris muris‐induced infection model of chronic colitis. Infection provoked severe transmural colonic inflammation by day 35 post‐infection. Colonic pathology, macrophage phenotype and cell death were determined. As predicted from the in‐vitro data, in‐vivo treatment of T. muris‐infected mice with IFX had no effect on clinical outcome, nor did it affect macrophage cell phenotype or number. IFX enhanced apoptosis of colonic immune cells significantly, likely to be driven by a direct effect of the humanized antibody itself. We have demonstrated that although IFX does not bind directly to TNF‐α, observed anti‐inflammatory effects in other mouse models may be through host cell apoptosis. We suggest that more careful consideration of xenogeneic responses should be made when utilizing IFX in preclinical models.

An anti-TNF-α antibody mimetic to treat ocular inflammation

“…It was not clear from the literature describing systemic use of infliximab in different preclinical models, whether it can bind to mouse TNF-α and therefore enable us to demonstrate efficacy in the EAU model161718. Ocular administration of infliximab has been shown to provide significant retinal and corneal protection in an mouse model of alkali injury19, as well as modulating choroidal neovascularization and endotoxin-induced inflammation in rat and rabbit experimental models respectively2021.…”

Combination of paromomycin plus human anti-TNF-α antibodies to control the local inflammatory response in BALB/ mice with cutaneous leishmaniasis lesions

“…In order to carry out these experiments, we chose human anti-TNF-α because previous works evidenced its anti-inflammatory effect in several mouse preclinical models of inflammation such as chronic colitis, diabetes and colon cancer [33,34]. It was further demonstrated that Infliximab triggers these effects independently of TNF-α neutralization [35] and principally through the induction of apoptosis and necrosis of host inflammatory cells provoked by the natural immunogenicity of Infliximab in mice. The fact that the use of human anti-TNF-α has no cross-reactivity with mice TNF-α [35] could explain the results obtained in the in vitro antileishmanial activity assay (Fig.…”

“…It was further demonstrated that Infliximab triggers these effects independently of TNF-α neutralization [35] and principally through the induction of apoptosis and necrosis of host inflammatory cells provoked by the natural immunogenicity of Infliximab in mice. The fact that the use of human anti-TNF-α has no cross-reactivity with mice TNF-α [35] could explain the results obtained in the in vitro antileishmanial activity assay (Fig. 1).…”

TNFα depleting therapy improves fertility and animal welfare in TNFα-driven transgenic models of polyarthritis when administered in their routine breeding

“…While hTNFtg and TNF ΔARE models of polyarthritis are driven by a common pathophysiology, infliximab is not reported to cross react with murine TNFα. 21 However, its efficacy has been reported in several murine models of chronic inflammation suggesting further modes of action beyond direct neutralization and depletion of TNFα. 15 – 19 These include the induction of T-cell apoptosis and suppression of angiogenesis, possibly mediated via Fc-mediated interactions and the natural immunogenicity of infliximab.…”