Severe anaphylactic reactions to glutamic acid decarboxylase (GAD) self peptides in NOD mice that spontaneously develop autoimmune type 1 diabetes mellitus

BMC Immunology BioMed Central Research article Open Access Severe anaphylactic reactions to glutamic acid decarboxylase (GAD) self peptides in NOD mice that spontaneously develop autoimmune type 1 diabetes mellitus Rosetta Pedotti†1,4, Maija Sanna†2, Mindy Tsai3, Jason DeVoss1, Lawrence Steinman1, Hugh McDevitt2 and Stephen J Galli*3 Address: 1Department of Neurology and Neurological Science, Stanford University School of Medicine, Stanford, California, USA, 2Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA, 3Department of Pathology, Stanford University School of Medicine, Stanford, California, USA and 4Neuroimmunology Unit, Instituto Neurologico C. Besta, Milan, Italy Email: Rosetta Pedotti - ; Maija Sanna - ; Mindy Tsai - ; Jason DeVoss - ; Lawrence Steinman - ; Hugh McDevitt - ; Stephen J Galli* - * Corresponding author †Equal contributors Published: 22 February 2003 BMC Immunology 2003, 4:2 Received: 8 October 2002 Accepted: 22 February 2003 This article is available from: http://www.biomedcentral.com/1471-2172/4/2 © 2003 Pedotti et al; licensee BioMed Central Ltd. This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original URL. Abstract Background: Insulin dependent (i.e., "type 1") diabetes mellitus (T1DM) is considered to be a T cell mediated disease in which TH1 and Tc autoreactive cells attack the pancreatic islets. Among the beta-cell antigens implicated in T1DM, glutamic acid decarboxylase (GAD) 65 appears to play a key role in the development of T1DM in humans as well as in non-obese diabetic (NOD) mice, the experimental model for this disease. It has been shown that shifting the immune response to this antigen from TH1 towards TH2, via the administration of GAD65 peptides to young NOD mice, can suppress the progression to overt T1DM. Accordingly, various protocols of "peptide immunotherapy" of T1DM are under investigation. However, in mice with experimental autoimmune encephalomyelitis (EAE), another autoimmune TH1 mediated disease that mimics human multiple sclerosis, anaphylactic shock can occur when the mice are challenged with certain myelin self peptides that initially were administered with adjuvant to induce the disease. Results: Here we show that NOD mice, that spontaneously develop T1DM, can develop fatal anaphylactic reactions upon challenge with preparations of immunodominant GAD65 self peptides after immunization with these peptides to modify the development of T1DM. Conclusions: These findings document severe anaphylaxis to self peptide preparations used in an attempt to devise immunotherapy for a spontaneous autoimmune disease. Taken together with the findings in EAE, these results suggest that peptide therapies designed to induce a TH1 to TH2 shift carry a risk for the development of anaphylactic reactivity to the therapeutic peptides. Background Type 1 diabetes mellitus (T1DM) is a T cell-mediated autoimmune disease characterized by lymphocytic infiltration of the pancreatic islets of Langerhans with subsequent destruction of the insulin-producing beta cells [1]. Non-obese diabetic (NOD) female mice, a murine model for T1DM, spontaneously develop diabetes by 30 Page 1 of 9 (page number not for citation purposes) BMC Immunology 2003, 4 weeks-of-age, with infiltrating cells appearing around the pancreatic islets as early as at 3–4 weeks-of-age [2]. T1DM susceptibility in the NOD mouse is linked to I-Ag7, the murine MHC class II gene that encodes a histidine at position 56 and a serine at position 57 in the β chain, in place of the more frequent proline 56β and aspartic acid 57β [3]. The development of diabetes is prevented in NOD.PD mice (which are NOD mice with I-Ag7) that carry a β chain transgene with site-specific mutations that restore proline and aspartic acid at positions 56β and 57β, respectively [4]. Furthermore, because of the two amino acid changes in the additional (transgenic) MHC class II allele β chain in NOD.PD mice, NOD.PD mice recognize three additional peptide epitopes in the glutamic acid decarboxylase 65 (GAD65) autoantigen [5]. Among beta-cell autoantigens, GAD65 is an important initial target of the immune response that results in beta-cell destruction and diabetes, in both humans and NOD mice [6–9]. While both humoral and cellular responses to GAD65 occur as early as 4 weeks of age in NOD mice [8], there is considerable evidence that beta-cell-specific TH1 cells are the effectors of T1DM, whereas TH2 cells appear to have a protective role [10]. Accordingly, a shift of the autoimmune response from TH1 to TH2 predominance has represented a promising strategy for prevention of diabetes and other TH1-mediated autoimmune diseases. For example, administration of GAD65 to young NOD mice has been shown to prevent insulitis and diabetes [8,9], apparently via induction of CD4+ regulatory T cells with a TH2 phenotype [10]. Similarly, treatment with immunodominant peptides of myelin can prevent or reverse experimental autoimmune encephalomyelitis (EAE), a TH1-associated inducible "autoimmune" disorder that is widely used as a model for human multiple sclerosis [11– 13]. Unfortunately, recent work indicates that the application of strategies to shift autoimmune responses from TH1 to TH2 predominance is not without risk. Thus, some of us recently showed that administration of two self peptides that can induce EAE, myelin proteolipid protein peptide 139 to 151 (PLP139-151) or myelin oligodendrocyte glycoprotein peptide 35–55 (MOG35-55), can result in severe anaphylactic reactions [14]. This result clearly indicated that severe allergic reactions to self peptides can occur in mice that have been induced to express pathology (i.e., EAE) related to "autoimmunity" to these peptides. However, it was initially unclear whether anaphylactic reactivity also could be elicited to self peptides that have been implicated in the development of a spontaneous autoimmune disorder. http://www.biomedcentral.com/1471-2172/4/2 In the present study, we show that anti-peptide autoantibodies and fatal anaphylactic reactions can be elicited by immunodominant GAD65 peptides in NOD mice that have been injected with these peptides intraperitoneally in incomplete Freund's adjuvant (IFA), as part of an attempt to induce "tolerance" and prevent the spontaneous development of T1DM. Moreover, while this manuscript was in review, Liu and colleagues reported that anti-peptide autoantibodies and fatal anaphylaxis can be induced in NOD mice that have been immunized with insulin B chain peptides B:9–23 or B:13–23 [15]. However, in the Liu et al. study, the peptides were administered subcutaneously in saline without adjuvant. As reviewed in Liu et al., [15] several lines of evidence indicate that amino acids 9– 23 of the insulin B chain also represent a major ta (...truncated)