Generation of T cell responses targeting the reactive metabolite of halothane in mice

Abstract

Immune-mediated adverse drug reactions (IADRs) represent a significant problem in clinical practice and drug development. Studies of the underlying mechanisms of IADRs have been hampered by the lack of animal models. Halothane causes severe allergic hepatitis with clinical features consistent with an IADR. Our ultimate goal is to develop a mouse model of halothane hepatitis. Evidence suggests that adaptive immune responses targeting liver protein adducts of the reactive metabolite (TFA) play an important role in the pathogenesis. The present study demonstrated that the combination of an anti-CD40 antibody and a Toll-like receptor (TLR) agonist served as a potent adjuvant in generating TFA-specific T cell responses in mice. Both CD4+ and CD8+ subsets of T cells were activated and the TFA-specific responses were detected not only in the spleen but also in the liver of mice immunized with mouse serum albumin adducts of TFA (TFA-MSA) plus the combined CD40/TLR agonist. Whereas all three TLR agonists examined were effective in eliciting TFA-specific immune responses in BALB/cByJ mice, only polyI:C was effective in DBA/1 mice and none of the TLR agonists could aid the generation of TFA-specific T cells in C57BL/6J mice. This result, combined with our previous finding that BALB/cByJ mice were the most susceptible to halothane-induced acute liver injury, provides the basis for employing this strain in future studies. Collectively, our data demonstrated the successful completion of a crucial first step in the development of a murine model of halothane hepatitis.

Idiosyncratic Adverse Drug Reactions: Current Concepts

“…Intraperitoneal injection of halothane in oil induced liver injury in mice and generated an innate immune response (You et al, 2006). Mouse strain-, age-, and sex-dependent variations in the severity of this injury were observed, including female sex and older age (Cheng et al, 2009You et al, 2010), which are analogous to the risk factors in humans. Moreover, this injury was increased by agents such as poly-IC that act through Toll-like receptors (Cheng et al, 2009).…”

Are drug metabolites able to cause T-cell-mediated hypersensitivity reactions?

“…Multiple hepatic proteins including calreticulin, protein X, carboxylesterase and the pyruvate dehydrogenase complex are conjugated with TFA-chloride indicating that multiple peptide epitopes will be available for T cells [37]. Although the nature of the drugspecific cellular immune response in patients with liver injury has not been studied, You et al found that both CD4 + and CD8 + T cells were activated in mice in response to the TFAreactive metabolite [38].…”

Effects of peptide fraction and counter ion on the development of clinical signs in experimental autoimmune encephalomyelitis

“…), and induce T‐cell responses (You et al . ). These observations raised the possibility that the higher TFA in MOG‐A was contributing to increased disease severity.…”

“…TFA has recently been shown to act as an allosteric modulator of glycine receptors, increasing receptor activity at lower glycine concentrations (Tipps et al 2012) and previously was shown to activate ATP sensitive potassium channels (Han et al 2001). In vivo, TFA can trifluoroacetylate amino groups in proteins and phospholipids (Satoh et al 1985), which can elicit antibody responses (Trudell et al 1991;Furst et al 1997), increase proinflammatory cytokine production (You et al 2006), and induce T-cell responses (You et al 2010). These observations raised the possibility that the higher TFA in MOG-A was contributing to increased disease severity.…”

“…During the course of comparing different commercial sources of MOG 35-55 peptide, we became aware that the peptide fraction differed substantially between preparations. As immunization with different doses of MOG can influence EAE disease (Sestero et al 2012;Naves et al 2013), and as TFA can influence cell growth and survival (Ma et al 1990;Cornish et al 1999), T-cell responses (Trudell et al 1991;Furst et al 1997;You et al 2006You et al , 2010, and the activity of certain receptors (Tipps et al 2012) and channels (Han et al 2001), results obtained with different MOG preparations may not be directly comparable. In this study, we report that immunization with a MOG 35-55 preparation of low peptide fraction led to significantly higher clinical scores than immunization with one of higher peptide fraction.…”