Human T cells expressing two additional receptors (TETARs) specific for HIV-1 recognize both epitopes

Area of Science:

• Immunology
• Molecular Biology
• Virology

Background:

• Adoptive T cell receptor (TCR) transfer is a promising immunotherapy strategy.
• Rapidly mutating targets like HIV-1 and cancer can evade immune responses through immune escape.
• Developing T cells that can recognize multiple viral or tumor antigens is crucial for effective immunotherapy.

Purpose of the Study:

• To engineer T cells expressing two distinct TCRs (TETARs) to simultaneously target multiple epitopes from HIV-1.
• To overcome TCR competition and functional impairment when expressing multiple TCRs in a single T cell.
• To evaluate the functionality and specificity of TETAR-expressing T cells against HIV-1 epitopes.

Main Methods:

• TCR mRNA electroporation was used to introduce two HIV-1 specific TCRs into T cells.
• Chimeric TCRs with human and murine constant domains were constructed to mitigate TCR competition.
• T cell responses, including cytokine secretion and cytotoxic activity, were assessed against target cells presenting specific epitopes.
• Single-cell analysis was performed to confirm dual epitope recognition by individual T cells.

Main Results:

• Simultaneous transfection of two TCRs initially led to competitive effects, which were overcome by modifying TCR constant domains and optimizing RNA amounts.
• The resulting TETAR-expressing T cells demonstrated functional responses, including cytokine secretion and cytotoxicity, to both targeted HIV-1 epitopes.
• Single-cell analysis confirmed that individual TETAR cells recognized both gag and nef epitopes.
• TETAR cells exhibited sequential killing of target cells presenting different epitopes, indicating sustained dual-specificity.

Conclusions:

• TETARs represent a sophisticated tool for studying TCR functionality and T cell behavior in response to multiple antigens.
• The engineered TETARs demonstrate the potential to overcome immune escape mechanisms employed by rapidly mutating viruses like HIV-1.
• This approach holds promise as a novel strategy for developing enhanced T cell-based immunotherapies against viral infections and cancer.