Improving the immune response through memory B cells – a healing exercise

Pathogens: immune cells against intractable viruses

Viral infections are not only common in times of a pandemic. Not all viruses that infect humans actually make us sick. The immune system often reacts quickly and successfully fights off intruders. However, some pathogens can overwhelm the immune system. Researchers are now reporting on what can help fight stubborn viruses.

As in the present Message The University of Basel explains that viruses such as HIV or the pathogen that causes hepatitis C can bypass the immune system. One way to develop vaccines against such a chronic infection so far has targeted the immune system’s so-called memory B cells. Researchers at the University of Basel have now discovered that these cells need the help of other memory cells in order to effectively defend the organism against chronic viruses.

Defense against pathogens

A huge arsenal of immune cells defends the organism against pathogens. In the case of virus infection, B cells produce appropriate antibodies that suppress the activity of the pathogen. Some of these B cells die again after infection or vaccination, but some of the B cells remain in the body as memory cells so that the correct antibodies can be produced more quickly if the same pathogen is re-infected. Vaccines target, among other things, the formation of these memory B cells.

But viruses such as HIV or hepatitis C have bypassed the memory B-cell defense – an obstacle to developing effective vaccines. In order to overcome this obstacle, scientists led by Professor D. Daniel Benschwer of the Department of Biomedicine at the University of Basel examines the reaction of immune cells in chronic viral infections.

“One of the problems is that memory B cells fall into a kind of panic reaction due to the constant presence of pathogens and the associated inflammation,” Benschwer explains. From the breeding and maturation program, they all switch to the method of antibody production and quickly perish. The research team is now reporting on possible treatments for this problem in the specialized journal “PNAS“.

Prevent panic reaction

For their experiments, the researchers studied infection of mice with a virus called lymphocytic choriomeningitis virus (LCMV), which causes chronic infection in animals. They discovered that memory B cells need the help of other immune cells for a sustained response to viruses: helper memory T cells, the formation of which can also be stimulated by appropriate vaccination strategies.

If scientists stimulate the formation of appropriate helper memory T cells in test animals prior to infection with LCMV, the latter prevents the panic reaction of memory B cells after infection.

“Instead of wasting the entire B-cell stock in the unsuccessful fight against the virus, thanks to the helper memory T cells, there remains a reserve of B cells that continue to multiply and mature and maintain the defense against the virus,” explains Dr. Christine Nar, lead author of the study.

To date, the role of helper memory T cells in chronic virus vaccination has not been sufficiently taken into account. “Knowledge that these cells can be used to promote a more sustainable immune response through memory B cells is of direct relevance to strategies for developing novel vaccines against HIV and hepatitis C,” Benschwer said. (ad)