High levels of immunoglobulin E autoantibody to 14-3-3 epsilon protein correlate with protection against severe Plasmodium falciparum malaria.

Plasmodium falciparum infection generally induces elevated total plasma levels of immunoglobulins, some of which recognize self- or parasite-specific antigens. To our knowledge, we are the first to report high levels of functional immunoglobulin E (IgE) autoantibodies recognizing brain 14-3-3 protein epsilon in asymptomatic P. falciparum malaria. 14-3-3 epsilon protein belongs to a family of proteins that binds to CD81, a member of the tetraspanin superfamily elicited in hepatocyte invasion by sporozoites. Levels of expression of 14-3-3 epsilon protein were found to be increased in vivo and in vitro during Plasmodium yoelii and P. falciparum intrahepatic development. Collectively, these results indicate that self-reactive IgE is produced during malaria. In addition, the negative correlation between levels of self-reactive IgE to 14-3-3 epsilon protein and parasitemia in asymptomatic malaria due to P. falciparum supports a role for these IgE molecules in defense mechanisms, probably by interfering with development of liver-stage parasites through the CD81 pathway.