Researchers at Harvard School of Public Health (HSPH) were attempting to identify the mechanism by which Plasmodium falciparum merozoites enter erthyrocytes, but instead found a parasite protein that is essential for escape from the cells. When the protein, P. falciparum calcium-dependent protein kinase (PfCDPK5), was suppressed the parasites were trapped in the host cell and unable to infect new cells. In further experiments the team showed that these merozoites were still able to invade erythrocytes if released from their host cell by other means, indicating separate mechanisms for invasion and egress from erythrocytes.
The findings reveal an essential step in the biology of P. falciparum and suggest a new, parasite-specific, drug target for fighting one of the world’s most common and dangerous infections. Whilst many scientists are looking for inhibitors of parasite egress and invasion of red blood cells, no anti-malarial drugs yet target these stages of the parasite lifecycle.
The study is published in Science.