Abstract
Design and Development of a Novel Vaccine for Protection Against Lyme Borreliosis
Lyme borreliosis is the most common vector-borne infection in the Northern hemisphere, with an estimated 300,000 cases per year in the United States. Despite the high incidence and significant consequences, there is currently no vaccine available to humans. Vaccines have been attempted in the past using outer surface protein A (OspA) from Borrelia burgdorferi as the antigen stimulating the immune response. This is one of the dominant antigens expressed by B burgdorferi when present in a tick. The species that causes Lyme disease in Europe varies from that found in the United States. The goal of this new vaccine is to target several pathogenic species through the development of a multivalent OspA vaccine in the hope of reducing the incidence of Lyme borreliosis.
To develop a vaccine, the researchers used the C-terminal end of the OspA protein because it is more distant from the bacterial surface and the majority of accessible epitopes have been localized there. The vaccine they produced included three proteins, each containing two OspA serotypes linked to a heterodimer. To preserve the vaccine’s stability at physiologic temperatures, disulfide bonds were introduced. After the development of the vaccine, mice were immunized 3 times with 3 μg vaccine. These mice were then challenged with, and shown to be protected against, infected ticks and in vitro grown spirochetes. Subsequent enzyme-linked immunosorbant assays induced a strong antibody response, confirming the protective potency of the vaccine.
Although this study was conducted in mice models, it lays the foundation for the generation of a vaccine against several Borrelia species. With future investigation, there is promise of a vaccine providing protection against Lyme disease in humans.
(PLoS ONE. 2014;9:1–12) P Comstedt, M Hanner, W Schüler, et al.
Prepared by Lindsey Caley, MD, University of Utah Wilderness Medicine Fellow, Salt Lake City, UT, USA.