# Duration of Initial Viremia Modulates Functional Properties of HIV-specific T Cell Receptors

## TL;DR

The study shows that starting HIV treatment early helps preserve better T cell responses, which could improve future HIV treatments.

## Contribution

The study reveals that early ART preserves higher-avidity TCRs and memory T cell profiles in HIV-specific repertoires.

## Key findings

- Early ART initiation preserves higher-avidity TCRs and transitional memory CD8+ T cell subsets.
- Prolonged antigen exposure enriches cross-reactive TCR clonotypes in HIV-specific repertoires.
- Functional differences in TCR repertoires are not linked to TRBV gene sharing patterns.

## Abstract

Virus-specific CD8+ T cells are crucial in controlling chronic human viral infections such as HIV-1, but the effect of persistent antigen exposure on T cell repertoire formation is not well understood. In this study, we examined epitope-specific CD8+ T cell repertoires in people living with HIV-1, where duration of viremia following hyperacute infection was modulated by the time of initiation of continuous suppressive antiretroviral therapy (ART). After ART-induced suppression of viremia in persons expressing the same HLA class I allele, we analyzed the impact of early (n=6) versus delayed (n=6) ART initiation on the clonotypic composition, cross-reactivity, functional avidity and memory differentiation profile of the HIV-specific T cell repertoire restricted by HLA-B*58:01. Using a panel of barcoded tetramers, we mapped T cell receptor (TCR) clonotypes specific for three dominant epitopes and their variants. Both groups exhibited polyclonal TCR repertoires with evidence of cross-reactivity, which was significantly enriched in donors with prolonged antigen exposure. Within this cohort, broadly cross-reactive clonotypes capable of recognizing all autologous variants were identified, but these were rare (<1%). Early ART initiation preserved repertoires characterized by higher-avidity TCRs and a relative enrichment of transitional memory CD8+ T cell subsets. These functional differences were not associated with differences in TRBV gene sharing, indicating that ART timing shapes repertoire quality and memory differentiation without altering TRBV gene bias. These findings demonstrate how antigen suppression dynamics differentially shape the breadth, functional sensitivity, and memory composition of the HIV-specific TCR repertoire, with implications for T cell-directed immunotherapies and HIV cure strategies.