(#29) Characterization of the anti-viral immune response against Coxsackievirus in type 1 diabetes

PRESENTED BY: Federica Vecchio

Authors
First NameLast NameAffiliation/Institution
AlexiaCarréUniversité de Paris, Institut Cochin, CNRS, INSERM, Paris, France
DaniilKorenkovUniversité de Paris, Institut Cochin, CNRS, INSERM, Paris, France
SoileTuomelaKarolinska Institutet, Dept. Medicine HS, Center for Infectious Medicine, Stockholm, Sweden
IsaacV. SnowhiteDiabetes Research Institute, Leonard Miller School of Medicine, University of Miami, USA
YannVerdierESPCI Paris, PSL University, Spectrométrie de Masse Biologique et Protéomique, CNRS USR3149, Paris, France
JoëlleVinhESPCI Paris, PSL University, Spectrométrie de Masse Biologique et Protéomique, CNRS USR3149, Paris, France
ZuzanaMarinicovaPaul Langerhans Institute, Technical University Dresden, Germany
SylvaineYouUniversité de Paris, Institut Cochin, CNRS, INSERM, Paris, France
RaphaelScharfmannUniversité de Paris, Institut Cochin, CNRS, INSERM, Paris, France
HeikkiHyotyPaul Langerhans Institute, Technical University Dresden, Germany
SallyC. KentUniversity of Massachusetts Medical School, Worcester, USA
MicheleSolimenaPaul Langerhans Institute, Technical University Dresden, Germany
AlbertoPuglieseDiabetes Research Institute, Leonard Miller School of Medicine, University of Miami, USA
MalinFlodström-TullbergKarolinska Institutet, Dept. Medicine HS, Center for Infectious Medicine, Stockholm, Sweden
RobertoMalloneUniversité de Paris, Institut Cochin, CNRS, INSERM, Paris, France
the nPOD-Virus Working Group  
 

Purpose

Despite accumulating epidemiological and histopathological evidence for an association between Coxsackievirus B (CVB) and type 1 diabetes (T1D), a causal link is missing. Very little is known about the T-cell response mounted against CVB infection and the epitopes targeted. Moreover, the upcoming T1D prevention trials using CVB vaccination require the exploration of possible cross-reactivities with islet antigens that may precipitate disease. We identified the HLA Class I (HLA-I) viral peptidome of CVB-infected beta cells and aimed to characterize the CD8+ T-cell response against these peptides.
 

Methods

HLA-I-bound peptides presented by CVB-infected human beta-cell lines were identified by mass spectrometry and those restricted for and confirmed to bind to HLA-A2 or -A3 were retained. We optimized the analysis of combinatorial HLA-I multimer assays and selected the immunodominant peptides recognized by circulating CD8+ T cells from CVB-seropositive healthy donors and in nPOD splenocytes. CD8+ T-cell clones were generated, and we evaluated the frequency and phenotype of CD8+ T cells recognizing the immunodominant CVB peptides thus identified in T1D and healthy children.
Summary of Results
Infected beta cells presented only few selected CVB peptides, and only a fraction of them was recognized by circulating CD8+ T cells from healthy seropositive donors. Moreover, only another sub-fraction of these epitopes was targeted by CD8+ T cells with an effector/memory phenotype. Although cross-reactivity with some islet antigens was documented, this was limited to subdominant CVB epitopes. Two major immunodominant epitopes were identified in both the blood and spleen. Ten clones generated from one donors against one of these immunodominant peptides were cytotoxic and carried the same TCR. The beta chain of this TCR was identical to that of 3.3% CD8+ T cells sorted from the pancreatic lymph nodes of a CVB+ HLA-I-matched T1D nPOD donor. The frequency and phenotype of circulating CD8+ T cells recognizing CVB epitopes in T1D and healthy children will be presented.
 

Conclusions

CVB infection seems to induce a limited CD8+ T-cell memory response in terms of antigen coverage, which may favor the repeated or chronic infections reported to be associated with islet autoimmunity. We will discuss whether this poor memory response is preferentially found in T1D children. The epitopes identified can be used to evaluate the efficacy of CVB vaccines. Moreover, their mapping to different CVB regions can distinguish the vaccinal response from that triggered by natural infection.