Virginia Commonwealth University School of Medicine researchers have made an important advancement toward developing a vaccine against the debilitating and potentially deadly tick-transmitted disease, human granulocytic anaplasmosis (HGA).
During the past several years, experts have seen a steady rise in the incidence of human infections caused by tick-transmitted bacterial pathogens - making the need for a vaccine critical. Successful vaccine development hinges on knowing what to target to prevent disease, and the VCU team has identified three such proteins on the surface of the HGA agent.
HGA is caused by a bacterium called Anaplasma phagocytophilum. HGA is transmitted by the same ticks that transmit Lyme disease, and it is the second most-common tick-borne disease in the United States. Between 2003 and 2012, the number of cases reported to the Centers for Disease Control and Prevention increased more than sixfold. However, evidence indicates that many more cases go undocumented. The disease is also found in Europe and Asia and can affect dogs, cats, horses and sheep.
In a study, published in the August issue of the journal Cellular Microbiology, researchers report the discovery of a protein called A. phagocytophilum invasion protein A, or AipA, found on the surface of the bacterium. It is a key player in mammalian cell invasion. They identified the specific region of this protein that is necessary for infection.
Further, they discovered that AipA works together with two other previously identified A. phagocytophilum surface proteins, OmpA and Asp14, to enable the pathogen to optimally invade host cells.