Abstract
Since December 2019, Coronavirus disease-19 (COVID-19) has spread
rapidly across the world, leading to a global effort to develop vaccines
and treatments. Despite extensive progress, there remains a need for
treatments to bolster the immune responses in infected immunocompromised
individuals, such as cancer patients who recently underwent a
haematopoietic stem cell transplantation. Immunological protection
against COVID-19 is mediated by both short-lived neutralising antibodies
and long-lasting virus-reactive T cells. Therefore, we propose that T
cell therapy may augment efficacy of current treatments. For the
greatest efficacy with minimal adverse effects, it is important that any
cellular therapy is designed to be as specific and directed as possible.
Here, we identify T cells from COVID-19 patients with a potentially
protective response to two major antigens of the SARS-CoV-2 virus, Spike
and Nucleocapsid protein. By generating clones of highly virus-reactive
CD4+ T cells, we were able to confirm a set of 9 immunodominant epitopes
and characterise T cell responses against these. Accordingly, the
sensitivity of T cell clones for their specific epitope, as well as the
extent and focus of their cytokine response was examined. Moreover, by
using an advanced T cell receptor (TCR) sequencing approach, we
determined the paired TCR sequences of clones of interest. While these
data on a limited population require further expansion for universal
application, the results presented here form a crucial first step
towards TCR-transgenic CD4+ T cell therapy of COVID-19.