T cells triggered by common cold also fend off Covid
High levels of protective immune cells that fight some common colds also made people less likely to contact Covid-19 in a study.
Researchers found higher levels of T cells against certain colds in people who didn’t develop Covid while living with someone who had the disease, according to a study. The prior illnesses were caused by other coronaviruses related to SARS-CoV-2.
The findings provide further evidence of the protective effects of T cells, an arm of the immune system that’s gaining attention as the pandemic stretches into its 3rd year and new variants like omicron erode vaccine protection.
Being exposed to the SARS-CoV-2 virus doesn’t always result in infection and we’ve been keen to understand why, said the study’s lead author and a researcher. We found that high levels of pre-existing T cells, created by the body when infected with other human coronaviruses like the common cold, can protect.
The UJ scientists analysed blood samples from 52 people who lived with someone who had tested positive for Covid, of which half didn’t become infected. Their conclusions show the protective role of T cells induced by other coronaviruses for the first time, they said.
Compared with antibodies, T cells tend to survive longer in the body and can kill infected cells, preventing serious illness. They also tend to attack a wider range of related pathogens than antibodies, which allows for a greater degree of cross-protection across different viruses or strains.
Universal vaccine
Antibodies elicited by Covid vaccines block the spike protein, which the virus uses to enter cells. Those shots tend to lose effectiveness when the spike undergoes significant mutations, as it has in the Omicron variant.
But T cells that were made in response to other coronaviruses target internal proteins within SARS-CoV-2, the scientists said. A similar approach could help with development of a universal vaccine that could prevent infection from current and future variants, the authors said.
The internal proteins targeted by the protective T cells we identified mutate much less, a scientist said. New vaccines that include these conserved, internal proteins against current and future variants.
There are various caveats to the findings. The study was small and 88 % of the participants were of white European ethnicity, according to the statement. The best way for people to protect themselves against Covid is still to be fully vaccinated, including getting a booster dose, the scientist said.