Thursday, April 3, 2025
4/3/2025
SARS-CoV-2-reactive tissue-resident memory T cells in healthy and cancer subjects - PROJECT SUMMARY This multi-PI proposal titled “SARS-CoV-2-reactive subjects” is written in response to ‘RFA-CA-20-039’ - tissue-resident memory T cells in healthy and cancer Research projects in SARS-CoV-2 Serological Sciences. Recent studies have shown that antibody responses to SARS-CoV-2 infection decline rapidly over time, implying a lack of durable protective humoral (B cell) immunity. Whether this is also true for cellular immunity (e.g., T cells) is poorly understood. It is well established that CD8+ TRM cells are the first line of defense in viral infections at mucosal/barrier sites. They are also known to protect hosts against homologous or heterologous re-infections. Our group was the first to show that TRM cells are pivotal players in driving effective anti-tumor immune responses in lung cancer, and that TRM cells are the primary cellular targets of anti-PD1 therapies. These key findings were possible because of the ongoing collaboration between Dr. Vijayanand, Dr. Ay, and Dr. Ottensmeier (Multi-PI). This team brings together experience in T cell immunology, single-cell genomics, bioinformatics, and cancer immunology. Our Multi-PI team has recently performed the first and largest single-cell RNA-seq and TCR-seq analysis of SARS-CoV-2-reactive CD8+ and CD4+ T cells (~300,000 single-cells) from COVID-19 patients. Here, to understand TRM responses to SARS-CoV-2, we will capitalize on a cohort of cancer (n=100) and non-cancer (n=100) patients, who will provide excess airway (nasal, oropharynx, larynx), lung and tumor tissue specimens obtained during routine surgery. In AIM 1, we will define the properties of SARS-CoV-2 reactive TRM cells from cancer and non-cancer patients with or without previous SARS-CoV-2 infection. We will perform combined single-cell RNA-seq and TCR-seq analysis of CD8+ TRM cells in the airways (nasal, oropharynx), lung, and tumor tissue. In parallel, by stimulating PBMCs with SARS-CoV-2 peptide pool, we will determine the transcriptomic and TCR sequence of SARS-CoV-2 reactive T cells. We will utilize this TCR sequence information to define the numbers and properties of SARS-CoV-2 reactive-TRM cells in mucosal and tumor tissues. Recent studies in non- exposed individuals (pre-COVID-19 pandemic) indicate pre-existing, circulating CD8+ T cells, with human coronavirus cross-reactivity. Here, we will measure the quantity and quality of pre-existing SARS-CoV-2 cross- reactive TRM responses in subjects without clinical or serological evidence of previous SARS-CoV-2 infection. In AIM 2, we will assess the impact of SARS-CoV-2 infection on anti-tumor and other anti-viral TRM responses. We will stimulate matched PBMCs (as above) with peptide pools targeting (i) common respiratory RNA viruses (influenza (FLU), RSV), (ii) persistent DNA viruses (CMV, EBV), and (iii) a tumor-driving virus (HPV) to define the TCR sequence of the respective virus-specific and tumor(HPV)-specific CD8+ T cells; we will utilize the TCR information to determine frequency and properties of other virus/tumor-reactive TRM cells in mucosal and tumor- tissue cells.
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