Malaria prevents the host body (human or mouse) from developing lasting immunity. A new University of Iowa study, led by microbiology professor John Harty, has homed in on a potential culprit of this immunosuppression. The molecule, CTLA-4, is produced by a type of immune cell called a Treg cell. Blocking CTLA-4 at the right time during blood-stage infection allows mice to quickly clear malaria. Importantly the treated mice also develop lasting immunity to malaria.
The video, captured with intravital confocal immunofluorescence microscopy, shows Treg cells (green) delivering CTLA-4 to B cell (blue/ magenta)-Helper T cell (red) clusters in the spleen of a mouse. The CTLA-4 molecule inhibits efficient production of antibodies against malaria.
If this pathway works in humans as it does in mice, blocking CTLA-4 might be a way to improve malaria treatment and boost immunity to reinfection. The study was published Sept. 11 online in Nature Medicine.