Diversity of T-cell antigen receptor Vβ gene utilization in advanced human atheroma

Abstract

Human atheromata contain T lymphocytes, but knowledge of the function and receptor specificity of these cells is limited. Immunohistochemical studies have established that T cells in advanced human carotid plaques express predominantly the α/β form of the T-cell receptor (TCR). We then compared the use of variable region genes of the β-chain (Vβ) of the TCR for antigen by analysis of 14 carotid plaques and peripheral blood samples obtained at carotid endarterectomy. We used a direct approach that avoids isolation and culture of T cells. RNA extracted from lesions and peripheral blood mononuclear cells was reverse transcribed and amplified by polymerase chain reaction (PCR) to determine rearrangements of 18 Vβ sequences. PCR products were visualized on Southern blots using a probe internal to the PCR primers. Input cDNA from lesions and peripheral blood was adjusted to yield equivalent signals for a conserved region of the TCR β-chain to permit comparisons. As expected, utilization of TCR Vβ genes in peripheral blood cells was nonselective: an average of 17 of 18 Vβ regions yielded signals (n=14). Frequency of variable-region gene usage in lesions and blood was highly concordant: of 252 sequences tested (14 samples, 18 sequences per sample), 240 were identified in peripheral blood versus 207 in plaques. Vβ genes 10 and 11 were not expressed in plaques, a significant difference when compared with peripheral blood (P=.0001 by χ2). However, the remaining 16 genes showed no significant differences. This analysis indicates that T cells generally express a diverse pattern of Vβ genes within complex human atheroma. © 1994 American Heart Association, Inc.