The T-cell receptor V beta gene usage in tumor-infiltrating lymphocytes and blood of patients with hepatocellular carcinoma

Abstract

To determine a possibly restricted T-cell receptor (TCR) repertoire in tumor-infiltrating lymphocytes (TIL) in response to tumor-associated antigens in patients with hepatocellular carcinoma (HCC), freshly isolated TIL (n = 5) and peripheral blood lymphocytes (PBL; n = 6; 3 paired with TIL) were studied for expression of TCR variable (V) beta regions. RNA purified from TIL or PBL was reverse-transcribed into complementary DNA. This complementary DNA was amplified by quantitative polymerase chain reaction with 22 primers specific for 20 TCR V beta gene families and a 3' constant (C) beta primer. As a reference for later quantitation, a fragment of TCR C alpha was coamplified with each V beta region. Using 32P-labeled 3' primers, the percentage of total V beta expression was calculated by measuring the cpm of each of the amplified products. In contrast to PBL of 6 control, healthy individuals, whose range of expression of each TCR V beta gene varied from 0 to 13%, the expression of some V beta genes in HCC TIL was as high as 33%, indicating a restricted TCR V beta usage in HCC TIL. When polymerase chain reaction-amplified complementary DNAs of the V beta 1 or V beta 3 genes obtained from two TIL preparations were cloned and sequenced, the same rearrangements were found in the majority of DNA clones. The particular V beta genes that were over- or underrepresented in TIL varied among the patients. In 3 of 6 PBL and 3 of 5 TIL, the V beta 3 gene was expressed with a relatively high frequency. The V beta 4 gene expression was consistently low in patients' TIL or PBL. In 3 paired PBL and TIL, V beta expression was similar. In 5 of 6 cases, HCC PBL had different TCR V beta frequencies from those seen in normal PBL. This analysis of TCR V beta usage in freshly isolated TIL and in PBL indicated that T-lymphocytes in patients with HCC might have restricted immunological reactivity and that V beta 3-restricted TIL might represent antitumor effector cells.