Background of the antigen
Borrelia burgdorferi is a spirochete and the cause of Lyme disease, a tick transmitted illness of humans and animals. B. burgdorferi may persist in humans and animals for months or years following initial infection, despite a robust humoral immune response. B. burgdorferi resembles other spirochetes in that it is a highly specialized, motile, two-membrane, spiral shaped bacteria which lives primarily as an extracellular pathogen. B. burgdorferi has an unusual genome compared with other eubacteria which includes a linear chromosome approximately one megabase in size and numerous linear and circular plasmids.