Malaria and vaccine immunology

Malaria and vaccine immunology

Mechanistic insights into the control of long-lived humoral immunity

Vaccines work by stimulating the immune system with components of pathogens without experiencing a fullblown infection. However, although the protective effect of most licensensed vaccines is very high, the durability of the protection varies widely between vaccines. The tick-borne encephalitis virus (TBEV) vaccine, e.g. needs to be boosted every three to five years while the measles vaccine generally generates protective immunity for the life-time of the individual. Live vaccines, such as the measles vaccine, generally induce immunity that lasts longer compared to inactivated- or subunit vaccines, such as the TBEV or tetanus vaccines, as they more closely mimick the natural infection. However, not all natural infections lead to long-lasting immunity. Individuals that were previously immune to malaria disease can become susceptible again after staying in non-endemic regions for a few years, indicating that malaria-specific immunity is very short-lived.

 

It is currently unclear why there is such a difference in the longevity of immunity and this is an important problem to solve, so that current and future vaccines can be improved and generate longer lasting immunity. To increase our understanding of the mechanisms that govern longevity of an immune response we use molecular approaches to investigate antigen-specific immune cells at different time-points after vaccination or infection that induce long- or short-lived immunity. This approach enable us to better understand how the immune cells are programmed in the context of long- vs short-lived immunity, and thereby help guide future vaccine efforts.

 

Changes to the immune landscape after malaria infection

Malaria infection is associated with a strong activation of the innate immune response. This activation is characterized by high levels of interferon gamma, which is characteristic of a Th1 immune response. The innate signal type and strength is important in shaping the size and direction of the adaptive immune response. In recent years, it has become clear that the strong Th1 signal observed during malaria infection may have implications for the longevity and reactivation of the adaptive immune response. Current projects investigate the immune landscape in individuals that experience malaria for the first time, or that have experienced malaria previously. Using mass cytometry, we have found that the innate and adaptive immune profiles differ in the monocyte, T cell, NK cell, and B cell compartments between the groups, findings that are currently being investigated further.

GruppChefPortlet

Team leader

Anna Färnert

E-mail

anna.farnert@ki.se

Job title

Professor, MD

House

BioClinicum J7:20

GruppChefPortlet

Team leader

Christopher Sundling

E-mail

christopher.sundling@ki.se

Job title

Assistant professor

House

BioClinicum J7:20