"How the parasite invades red blood cells is not completely understood," said Dr. Jose Stoute of the Pennsylvania State University College of Medicine, who led the international team of researchers. "For many years it has been known that proteins called glycophorins are used by the parasite to gain entry into the red cell."
But the scientists said since infection can take place without glycophorins, it was suspected another protein also was involved. The identity of that protein -- nicknamed the "X" receptor -- has now been identified by the researchers as the complement receptor 1, or CR1, which is also known to help protect red cells from attack by the immune system.
"Our findings suggest that for many malaria strains, CR1 is an alternative receptor to glycophorins on intact red cells," Stoute said. "This work has important implications for the future development of a vaccine against malaria, therefore it is imperative that all the major invasion pathways be represented in a future malaria blood stage vaccine."
The study that included scientists from the Walter Reed Army Institute, Panama's Institute for Advanced Science and High Technology Studies, the Biomedical Instrumentation Center at the University of the Health Sciences, the University of Massachusetts Medical School and the Harvard Medical School appears in the journal PLoS Pathogens.