Researchers uncover a new player in vaccine induced immunity

Dr Harry Sutton

Researchers at the John Curtin School of Medical Research (JCSMR) have uncovered an alternative lineage of B cells which broadens our understanding of the impact malaria has on the immune system.

This alternative lineage was previously thought to be atypical B cells as a result of malaria infection. The researchers showed these cells are induced in patients who have received the malaria vaccine, without ever being exposed to malaria.

The finding of this alternative lineage has been published today in Cell Reports and was discovered by using new technology that looks at individual cell characteristics.

B cells are responsible for making antibodies, which can control infections such as SARS-CoV-2 and malaria. They remain long after infections have been cleared providing long term immune memory.

However, some infections, like malaria and human immunodeficiency virus (HIV), fail to induce good antibody responses and instead induce the production of large numbers of so-called “atypical” B cells.

“These ‘atypical’ B cells have been thought to be defective and unable to protect against reinfection” said Dr Harry Sutton, postdoctoral research in the Cockburn Group at JCSMR and first author of the study.

“To understand where these atypical cells come from, we compared immune cells from a population of Canberrans, who are unlikely to have been exposed to malaria, with a population in Kenya – where malaria is endemic.”

“A highly sensitive technique known as single cell sequencing revealed that the Canberran population do have these ‘atypical’ B cells that have mainly been found in patients with HIV and malaria.”

Traditional methods used to study these cells, such as flow cytometry, had not revealed the extent to which the immune cells were present in people that had not been exposed to malaria.

“By using single cell sequencing we could look at the markers on individual cells in the immune system” said Dr Sutton.

“We have shown that this is an alternative lineage of B cells which is abundant, even in people who have not been exposed to malaria.”

The researchers went on to show that these atypical cells are induced by vaccines for malaria that are effective in blocking infection, and also after people receive their flu shot.

“These ‘atypical’ B cells are not necessarily an indicator of disease, instead they are likely to have an actual function in our immune system” said Associate Professor Ian Cockburn, group leader and chief investigator of this research.

“The next step in this research is to find out what these B cells do.”

“If they contribute to healthy immune response, they may be a target of vaccine strategies.”