Erythrocyte binding ligand region VI specific IgA confers tissue protection in malaria infection.

A direct role for IgA either for elimination of malaria parasite or for improvement in tissue pathology has not been investigated in case of Malaria infection while IgG, IgE and IgM were all implicated in the adverse pathology. In this communication, we delineate further that Malaria specific IgA appears to be significant among individuals who had multiple episodes of infection. Interestingly, the IgA elicited by immunization of the homologous peptides derived from Plasmodium berghei ANKA have also resulted in protection of host from adverse lung pathology, while the parasite load is unaffected. The PfrVI immunized mice and mice infected with repeated cycles of 'infection and recovery', simulating an endemic like situation, have resulted in development of B cell population that secretes the IgA specific to this region VI. Summarily, our results suggest that the IgA specific to the malarial antigen can confer significant advantage to hosts in protecting the overall tissue pathology.

Kix domain specific Immunoglobulin A can protect from adverse lung and cerebral pathology induced by Plasmodium berghei ANKA.

Plasmodium specific IgA has been detected in serum and breast milk among the endemic population but the role it can play in vivo is not clear. In this report, we demonstrate the utility of Malaria specific IgA, elicited by peptide sequences (referred as Mpep3 and Mpep4) of region VI of EBA-175 (PfrVI). Immunization of mice with KLH tagged or untagged peptides of Mpep3, Mpep4 or with PfrVI have resulted in specific IgA response that inhibits the in vitro invasion of Plasmodium falciparum merozoites. Mice having the IgA specific to Mpep4 have exhibited higher tolerance to Plasmodium berghei ANKA parasitemia, exhibited several fold lesser sequestration of infected RBC, lesser damage to microvasculature with no signs of perivascular haemorrhage and lesser lung inflammation in comparison to unimmunized mice. In addition, the immunized mice have B-cell population that secrete the IgA specific to PfrVI. These results suggest that the IgA specific to these malarial antigens can confer significant advantage to hosts and it may also reduce the severity of malaria infection.