Ex vivo detection of myelin basic protein‐reactive T cells in multiple sclerosis and controls using specific TCR oligonucleotide probes

Abstract

T cell reactivity to candidate myelin autoantigens, such as myelin basic protein (MBP), may play an important role in the pathogenesis of multiple sclerosis (MS). Although MBP-reactive T cells have been found to undergo in vivo activation in patients with MS, their true precursor frequency in MS is unknown as current frequency analysis is commonly based on the T cell functional responses to MBP. In this study, we developed a TCR sequence-based ex vivo detection system using colony hybridization with oligonucleotide probes specific for CDR3 of selected T cell clones for the analysis of true T cell precursor frequency in PBMC. The results revealed that the precursor frequency of five independent T cell clones recognizing the immunodominant MBP 83-99 region was found to be in the range of 1.6×10 -4 in total T cells in three HLA-DR2 patients with MS compared to that of 0.25×10 -4 in HLA-DR2 healthy individuals. The observed frequency of MBP 83-99 -reactive T cells in MS patients was considerably higher than those measured in parallel by cell culture-based analysis (2.3×10 ) in the same peripheral blood mononuclear cell specimens. Furthermore, the study showed that MBP 83-99 -reactive T cells detected ex vivo belonged to CD45RA + , CD25 + and CD95 -T cell subsets as evidenced by preferential expression of specific TCR transcripts in these cell fractions.

T‐helper 17 cells expand in multiple sclerosis and are inhibited by interferon‐β

“…The frequency of MPB-specific IL-17-producing cells was in the range reported for MPBspecific IFN-␥-producing cells in MS patients. 31 In addition, the increased percentage of IL-22-producing CD4 ϩ T cells in AMS strengthens the association between Th17 and MS exacerbation, as this cytokine is related to the Th17 subset. 8 Conversely, the expression of IL-23R, which did not vary significantly among HS, AMS patients, and IMS patients, was similar in Th17 and Th1 (not shown) cells, in accordance with AcostaRodriguez and colleagues' 32 report.…”

Increased Frequencies of Myelin Oligodendrocyte Glycoprotein/MHC Class II-Binding CD4 Cells in Patients with Multiple Sclerosis

“…Limiting dilution frequency analysis has suggested that autoreactive T cells are found at approximately the same frequency in normal individuals as compare to patients with MS (5–8, 17). However, in subjects with MS, autoreactive T cells are in a more activated state as compared to T cells from normal individuals (9–11).…”

“…We first identified T cell epitopes of myelin basic protein and proteolipid protein in both patients with MS and healthy controls over two decades ago and have demonstrated minor differences in the frequency of antigen reactive cells in patients as compared to controls (6–8, 11, 14, 15); these autoreactive T cells can persist over long periods of time in patients (16, 17). Myelin oligodendrocyte glycoprotein (MOG) is another potentially important autoreactive T cell target in MS patients with epitopes identified that are restricted in the context of HLA DRB1*0401 and HLA DRB1*1501 (18–22).…”

Altered naive CD4 and CD8 T cell homeostasis in patients with relapsing-remitting multiple sclerosis: thymicversusperipheral (non-thymic) mechanisms

“…Thus, an important issue is the basis of the low naive CD8 T cell sjTREC levels in RRMS. We think it unlikely that the reduced sjTREC levels in this subset are due to antigen‐induced triggering of naive T cells, as the number of autoreactive T cells in the MS autoimmune response represent only a minor component of the peripheral naive T cell repertoire [32]. Our finding of a progressive and significant decrease in naive CD8 T cell sjTREC levels in healthy controls with increasing age confirms that thymic production is the main influence on the naive T cell niche in healthy controls [18,19,33,34].…”