Comparison of T-cell receptor repertoire restriction in blood and tumor tissue of colorectal cancer patients

Abstract

Several immunotherapeutic approaches rely on antigen-specific T-cells. Restrictions in the T-cell receptor (TCR) repertoire were reported as indicator of anti-tumor cytotoxic T-lymphocyte (CTL) response in various tumor entities. It is unclear yet whether a TCR restriction in peripheral blood mirrors the tumor compartment. We compared the expression of TCR Vβ-families for the quantification of TCR repertoire alterations in blood and tissue samples from patients with colorectal carcinoma. Blood samples from patients with colorectal carcinoma and healthy volunteers and tissue samples of normal colonic mucosa and colorectal carcinoma were analyzed. Relative Vβ-family quantification was performed based on quantitative reverse transcribed PCR. Standard deviation and average mean of the single families were determined. Two variables describing the degree of Vβ-repertoire restriction were defined. Forty-eight blood samples and 37 tissue samples were analyzed. TCR repertoire restriction was higher in blood of tumor patients than in blood of healthy controls (p < 0.05). No difference in the degree of TCR repertoire restriction was found between carcinoma and unaffected colon tissue. We found no corresponding elevated TCR families among the different compartments blood, normal colon, and carcinoma tissue of the same patient. In conclusion, we observed a repertoire restriction in peripheral blood as well as in tumor tissue of cancer patients. However, in tumor tissue, repertoire alterations were comparable to normal mucosa, suggesting compartment-specific TCR distribution rather than alterations due to tumor-T-cell interaction questioning the presence of highly restricted clonal T-cell expansions in colorectal cancer as they have been described in other, assumingly more immunogenic tumor entities.

Tumor-infiltrating lymphocytes in colorectal tumors display a diversity of T cell receptor sequences that differ from the T cells in adjacent mucosal tissue

“…Like Ochsenreither et al [24] we find that the V gene usage and CDR3 length are conserved between these two tissue types (Fig. 3).…”

Characterization of the T cell repertoire by deep T cell receptor sequencing in tissues and blood from patients with advanced colorectal cancer

“…However, to the best of our knowledge, no previous studies have investigated the clonality or functionality of the T cells. In the present study, next-generation sequencers were used to comprehensively analyze the TCR repertoire in the tissue and blood samples obtained from advanced CRC patients that had been treated with cancer peptide vaccines in combination with oxaliplatin-based chemotherapy, and it was confirmed that the T cell repertoires in tissues varied from the T cell repertoires in blood samples, as previously described ( 22 – 27 ). Although previous studies only analyzed TCR clonotypes.…”

Tumor-infiltrating lymphocytes in colorectal tumors display a diversity of T cell receptor sequences that differ from the T cells in adjacent mucosal tissue

“…Given the variation in the TCRB repertoire diversity between mucosal tissue and matched tumor tissue, we tested to see if other measures of TCRB repertoire were divergent between the two tissue types. Like Ochsenreither et al [24] we find that the V gene usage and CDR3 length are conserved between these two tissue types (Fig. 3).…”