Quantitative Longitudinal Analysis of T Cell Receptor Repertoire Expression in HIV-Infected Patients on Antiretroviral and Interleukin-2 Therapy

Abstract

We have developed a single-step reverse transcriptase kinetic PCR assay (kRT-PCR) to accurately determine the expression of each of the 24 TCRβV gene families in CD8⁺ cells. We analyzed the long-term effects of highly active antiretroviral therapy (HAART) on the stability of the CD8⁺ T cell receptor (TCR) repertoire in a cohort of 15 treated and 10 untreated individuals diagnosed with human immunodeficiency virus (HIV) infection. The CD4⁺ TCR repertoire was studied in a second cohort receiving interleukin-2 infusions in addition to HAART. Analysis was based on kinetic (quantitative) reverse-transcription PCR (kRT-PCR) of the TCR variable B gene (TCRβV). Expression of each of the 24 Vβ families was assessed at baseline immediately after infection and following initiation of HAART at 2, 4, 12, 24, and up to 192 weeks in 24-week intervals. Statistically significant family-specific expression changes were observed between treated and untreated individuals for 10 TCRβV families. Overall, when compared to untreated patients, a more stable expression of TCR genes was observed for HAART-treated individuals. Interestingly, this difference did not correlate with either CD4 or CD8 counts, which follow the expected curves for treated and untreated patients. When we applied our quantitative analysis to IL-2-treated patients we observed a rapid polyclonal activation of the repertoire. These results suggest that homeostasis in the T cell receptor repertoire is more robust in those patients who stay on HAART for a long time and confirm the polyclonal stimulating capacity of IL-2.