Outer Surface Protein A (OspA)

Outer surface protein A (OspA) is a major outer membrane lipoprotein found on the surface of Borrelia burgdorferi, the causative agent of Lyme disease. OspA is highly immunogenic and plays a critical role in the bacterium's lifecycle, particularly during its residence in the tick vector. It mediates adherence to tick midgut cells, provides protection against host antibodies, and its expression is tightly regulated, being high during the tick phase and downregulated upon entry into mammalian hosts. The variable region on its C-terminal domain influences vaccine effectiveness worldwide due to differences in immune recognition across geographic regions.

Vaccine antigen to induce neutralizing antibodies.