# Development of potent HLA-A02:01-restricted peptide-based cytotoxic T-cells against SARS-CoV-2 infections in patients awaiting a kidney transplant

## TL;DR

Researchers developed a method to expand virus-specific T cells in kidney transplant candidates, offering a potential treatment for SARS-CoV-2 infections.

## Contribution

A scalable method for in vitro expansion of SARS-CoV-2-specific CD8+ T cells using peptide-conjugated microspheres.

## Key findings

- The method achieved up to 200-fold increase in S-specific CD8+ T cells in 34.3% of kidney transplant candidates.
- SARS-CoV-2-specific CD8+ T cells exhibited effector-memory markers and antigen-specific cytotoxic activity.
- The approach works for both healthy individuals and patients with kidney diseases.

## Abstract

Controlling viral infections prior to solid organ transplantation is vital for successful engraftment and overall well-being of patients. One promising approach involves the deployment of viral antigen-specific cytotoxic T cells to eradicate viral pathogens. Although there have been attempts to develop anti-viral vaccines in the literature, the limited number of virus-specific cells which can be generated in vitro in the autologous system make it impracticable for autologous therapy.

We developed a straightforward and scalable method for the in vitro expansion of SARS-CoV-2 Spike S1 peptide-specific cytotoxic CD8+ T cells. This was achieved through combinatorial stimulation with S peptide-conjugated polystyrene microspheres in the presence of cytokines IL-2, IL-7, and IL-15 for 14 days.

Using A2/S269-specific tetramers as markers, we compared induction of S-specific CD8+ T cells from patients awaiting kidney transplantation (n=67) with that of normal controls (n=65). We found that this method has the potential to achieve at least a 10-fold up to 200-fold increase in S-specific CD8+ T cells in 34.3% of kidney transplant candidates and 36.9% of normal controls, respectively. These SARS-CoV-2 specific CD8+ T cells released inflammatory cytokines, expressed effector-memory T cells markers, and killed target cells in a dose-dependent and antigen-specific manner.

Our study demonstrates that viral antigen-specific cytotoxic CD8+ T cells can be robustly enriched in vitro from peripheral blood mononuclear cells of both healthy individuals and patients with kidney diseases using peptide-conjugated microspheres. Our findings provide novel insights into a potential therapeutic approach, using autologous anti-viral CD8+ T cells for transplant recipients/candidates.