T cell responses against Variants

T cell responses against Variants

Context: Researchers have found that T cells from people who have recovered from Covid-19, or received the Moderna or Pfizer-BioNTech vaccines, are still able to recognise several SARS-CoV-2 variants of concern.  It found that both “helper” T cells and “killer” T cells can still recognise mutated forms of the virus.

Concept:

• The researchers tested T cell responses against Alpha, Beta, Gamma and Epsilon. They found that both vaccinated individuals and the recovered patients had cross-reactive T cells that could target these variants.

What are T Cells?

• T cells (also called T lymphocytes) are one of the major components of the adaptive immune system.
• Their roles include directly killing infected host cells, activating other immune cells, producing cytokines and regulating the immune response.
• There are two major types of T cells: the helper T cell and the cytotoxic T cell.
• As the names suggest, helper T cells ‘help’ other cells of the immune system, whilst cytotoxic T cells kill virally infected cells and tumours.