Clonally expanded T cells from skin biopsies of patients with systemic sclerosis recognize DNA topoisomerase I and cytomegalovirus antigens (HUM3P.258)

Abstract

Systemic sclerosis (SSc) is a chronic autoimmune disease, characterized by immune system dysregulation, uncontrolled deposition of collagen and microvascular damage in the skin and several internal organs. T cells have a key role in the initiation and propagation of SSc. Our laboratory has previously identified the presence of high proportions of identical α- and β-chains TCR transcripts in skin biopsies from patients with SSc of recent onset, demonstrating clonal expansion of T cells in response to one or more antigens. In order to identify these antigens, pairs of those in vivo clonally expanded α- and β-chain TCR transcripts from two patients with SSc (SSc-21 and SSc-22) were expressed in mutant TCR negative T cells, J.RT3-T3.5, generating a total of 52 T cell lines, including 10 controls. An intracellular Ca2+ mobilization assay was employed to examine whether these transduced Jurkat T cell lines recognize putative SSc antigens presented by autologous EBV-transformed B cell lines. The self-antigen, DNA topoisomerase I and CMV and parvovirus antigens were tested. Statistically significant intracellular Ca2+ mobilization was observed in response to 3 DNA topoisomerase I and 2 CMV peptides by 5 T cell lines expressing clonally expanded α- and β-chain TCR transcripts from patient SSc-21 and SSc-22. These results demonstrate that clonally expanded T cells recognizing DNA topoisomerase I or CMV antigens are present in skin biopsies of recent onset of patients with SSc.