Molecular mimicry between Anoctamin 2 and Epstein-Barr virus nuclear antigen 1 associates with multiple sclerosis risk

Abstract

Multiple sclerosis (MS) is a chronic inflammatory, likely autoimmune disease of the central nervous system with a combination of genetic and environmental risk factors, among which Epstein-Barr virus (EBV) infection is a strong suspect. We have previously identified increased autoantibody levels toward the chloride-channel protein Anoctamin 2 (ANO2) in MS. Here, IgG antibody reactivity toward ANO2 and EBV nuclear antigen 1 (EBNA1) was measured using bead-based multiplex serology in plasma samples from 8,746 MS cases and 7,228 controls. We detected increased anti-ANO2 antibody levels in MS (P = 3.5 × 10−36) with 14.6% of cases and 7.8% of controls being ANO2 seropositive (odds ratio [OR] = 1.6; 95% confidence intervals [95%CI]: 1.5 to 1.8). The MS risk increase in ANO2-seropositive individuals was dramatic when also exposed to 3 known risk factors for MS: HLA-DRB1*15:01 carriage, absence of HLA-A*02:01, and high anti-EBNA1 antibody levels (OR = 24.9; 95%CI: 17.9 to 34.8). Reciprocal blocking experiments with ANO2 and EBNA1 peptides demonstrated antibody cross-reactivity, mapping to ANO2 [aa 140 to 149] and EBNA1 [aa 431 to 440]. HLA gene region was associated with anti-ANO2 antibody levels and HLA-DRB1*04:01 haplotype was negatively associated with ANO2 seropositivity (OR = 0.6; 95%CI: 0.5 to 0.7). Anti-ANO2 antibody levels were not increased in patients from 3 other inflammatory disease cohorts. The HLA influence and the fact that specific IgG production usually needs T cell help provides indirect evidence for a T cell ANO2 autoreactivity in MS. We propose a hypothesis where immune reactivity toward EBNA1 through molecular mimicry with ANO2 contributes to the etiopathogenesis of MS.

Infections, Vaccines and Autoimmunity: A Multiple Sclerosis Perspective

“…The prevalent intracerebral EBV presence has been also demonstrated in a recent study where up to 93% of examined MS brain samples exhibit expression of EBV latent membrane protein 1 (LMP-1) and EBV-encoded RNA [44]. In terms of molecular mimicry, a recent study has shown partial complementary sequences and antibody cross-reactivity between EBNA-1 and newly proposed MS antigen of anoctamin 2 (CNS-based ion channel) [45]. A selected group of MS patients (approximately 32%) do present with increased reactivity towards Anoctamin 2 and may represent an EBV-induced MS sub-phenotype [46].…”

Antibodies from multiple sclerosis brain identified Epstein-Barr virus nuclear antigen 1 & 2 epitopes which are recognized by oligoclonal bands

“…EBNA1 is an important viral protein expressed in Burkitt's Lymphoma (Rowe et al, 2014) as well as during various latency phases (Latency I, I/II, II, III) in EBVassociated malignancies (Shannon-Lowe and Rickinson, 2019). EBNA1 has long been recognized as an antigen in MS in the contexts of both antibody (Comabella et al, 2010;Farrell et al, 2009;Hecker et al, 2016;Honarmand et al, 2015;Lunemann et al, 2008a;Mameli et al, 2014;Nociti et al, 2010;Sundqvist et al, 2012;Tengvall et al, 2019) and T cell targets (Lunemann et al, 2006;Ramasamy et al, 2020). Some studies include both B and T cell responses to EBNA1 (Comabella et al, 2012;Lunemann et al, 2008b;Lunemann et al, 2010;Mameli et al, 2016;Pender et al, 2017;Pender et al, 2009).…”

Effects of Pregnancy and Hormones on T cell Immune Regulation in Multiple Sclerosis

“…Regarding environmental factors, it has been shown that migrants moving from a low-risk to a high-risk country have a higher than expected MS prevalence and vice versa (Ahlgren et al 2010, Ahlgren et al 2012, Berg-Hansen and Celius 2015, which supports the importance of lifestyle and environmental factors in risk of developing MS. Indeed, several factors have been shown to increase the risk of MS (Waubant et al 2019), in particular smoking and Epstein-Barr virus (EBV) infection (Hedström et al 2013, Hedström et al 2016, Tengvall et al 2019; Figure 3). On the contrary, the use of oral tobacco, high coffee and alcohol consumption could reduce the risk.…”

“…Several lines of evidence support the relevance of myelin-reactive CD4 + T cells although direct evidence is still missing (Hohlfeld et al 2016). Recently, other plausible autoantigens in MS have been suggested (Ayoglu et al 2016, Planas et al 2018, such as anoctamin 2, a Ca 2+ activated chloride channel expressed in nerve cells (Ayoglu et al 2016, Tengvall et al 2019. Irrespective of target antigen, the presence of autoreactive lymphocytes, in combination with the strong major histocompatibility complex (MHC) association, implies that there is an autoimmune component to the disease.…”

“…How the T cells specific towards CNS antigens become activated in the periphery still remains unclear, although mechanisms such as molecular mimicry, cross-reactivity, epitope spreading and bystander activation have been suggested (Riedhammer and Weissert 2015). A recent study suggests that immune reactivity toward an antigen associated with EBV, a common risk factor in MS, could speculatively contribute to disease through molecular mimicry with the proposed autoantigen anoctamin 2 (Tengvall et al 2019). Nevertheless, peripheral activation of autoreactive TH cells sets the stage for the inflammatory response and changes in the proportion of activated TH cells have been associated with disease activity (Khoury et al 2000, Jensen et al 2004, which further highlights the importance of T cell activation in the disease pathogenesis.…”