Negative Finding in Cross-Protective Activity of Japanese Borrelia Isolates against Infection with Three Species of Lyme Disease Borrelia in Outbred Mice

Outer surface protein A (OspA) is the most promising candidate for a component vaccine against Lyme disease caused by Borrelia burgdorferi sensu lato. Active cross-protection using a whole-cell vaccine prepared from strains belonging various OspA serotypes observed in Japan and worldwide was examined. No cross-protection was obtained by heterologous OspA-serotype vaccines. Since OspA is a highly variable protein expressed by Borrelia, this suggests that immunologically different OspA serotypes need to be combined for the development of an effective vaccine in Japan.