Successful vaccination for Lyme disease: a novel mechanism?

Borrelia burgdorferi sensu lato is the aetiologic agent of Lyme disease, which is a multi-system disorder resulting from the transmission of organisms from an infected tick. According to the US Centers for Disease Control, the incidence of Lyme disease in the US has increased 25-fold since national surveillance began and the geographical spread of Lyme disease causing spirochetes would indicate that the annual number of cases will continue to rise. Humoral immunity has been shown to play a role in protection and this has spurred efforts towards developing a Lyme disease vaccine. A number of protective immunogens have been characterised to date, but due to the heterogeneity of Lyme disease Borreliae, no single molecule has proven to be completely effective as a vaccinogen. This review will describe the immunogens that have been used to protect against B. burgdorferi infection, with a focus on the inherent challenges involved with providing successful immunity to B. burgdorferi. In addition, the promising aspects and the limitations of each protective immunogen will be discussed.