# Functional and dysfunctional human CD4 T cell and B cell responses to bacteria and viruses

> **NIH NIH U19** · LA JOLLA INSTITUTE FOR IMMUNOLOGY · 2021 · $1,263,917

## Abstract

PROJECT SUMMARY
Pre-existing T cell memory to SARS-CoV-2 is detectable in ~50% of people. We first reported this, and we have
since shown that this may largely be due to crossreactive memory CD4+ T cells from common cold coronavirus
(CCC) infections. While this observation has been reproduced on three continents, the big unanswered question
is whether these crossreactive memory T cells (i) confer some form of protection against COVID-19 disease
severity, (ii) have no impact on COVID-19 severity, or (iii) increase COVID-19 disease severity. This issue has
been widely discussed in scientific, public, and political spheres, and it potentially has major ramifications for
understanding the COVID-19 pandemic. The direct experiment to address this topic is a longitudinal study of
uninfected individuals at risk for acquisition of SARS-CoV-2, then assessing COVID-19 disease severity in
individuals who contract SARS-CoV-2 infection, stratified between individuals who did or did not have pre-
existing T cell memory to SARS-CoV-2.

## Key facts

- **NIH application ID:** 10285994
- **Project number:** 3U19AI142742-02S2
- **Recipient organization:** LA JOLLA INSTITUTE FOR IMMUNOLOGY
- **Principal Investigator:** Shane P Crotty
- **Activity code:** U19 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $1,263,917
- **Award type:** 3
- **Project period:** 2020-11-17 → 2023-02-28

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10285994

## Citation

> US National Institutes of Health, RePORTER application 10285994, Functional and dysfunctional human CD4 T cell and B cell responses to bacteria and viruses (3U19AI142742-02S2). Retrieved via AI Analytics 2026-05-21 from https://api.ai-analytics.org/grant/nih/10285994. Licensed CC0.

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