Presently, the rhesus macaque is the only nonhuman primate animal model utilized for the study of Lyme disease. While this animal model closely mimics human disease, rhesus macaques can harbor the herpes B virus, which is often lethal to humans; macaques also do not express the full complement of immunoglobulin G (IgG) subclasses found in humans. Conversely, baboons contain the full complement of IgG subclasses and do not harbor the herpes B virus. For these reasons, baboons have been increasingly utilized as the basis for models of infectious diseases and studies assessing the safety and immunogenicity of new vaccines. Here we analyzed the capability of baboons to become infected with Borrelia burgdorferi, the agent of Lyme disease. Combined culture and PCR analyses of tick-and syringe-infected animals indicated that baboons are a sufficient host for B. burgdorferi. Analysis of the antibody responses in infected baboons over a 48-week period revealed that antibodies are generated early during infection against many borrelial antigens, including the various OspE, OspF, and Elp paralogs that are encoded on the ubiquitous 32-kb circular plasmids (cp32s). By using the baboon sera generated by experimental infection it was determined that a combination of two cp32-encoded lipoproteins, OspE and ElpB1, resulted in highly specific and sensitive detection of B. burgdorferi infection. An expanded analysis, which included 39 different human Lyme disease patients, revealed that a combination of the OspE and ElpB1 lipoproteins could be the basis for a new serodiagnostic assay for Lyme disease. Importantly, this novel serodiagnostic test would be useful independent of prior OspA vaccination status.Lyme disease, the most common arthropod-borne disease in North America (49,50,70), is a multisystem disorder characterized by dermatologic, cardiac, neurologic, and arthritic manifestations (68, 69). Lyme disease pathogenesis and Borrelia burgdorferi infectivity have been studied in numerous animal models; however, the disease manifestations observed vary widely among host species (9). The murine model of Lyme disease has been the most intensively investigated and is presently the preferred animal model for Lyme disease research. The mouse model has allowed researchers to gain valuable insight into the effects of various components of the immune system in relation to Lyme disease pathogenesis (10, 13, 57, 64, 68, 69). However, there are drawbacks to the mouse model of Lyme disease. For instance, the mouse immune system and how it responds to B. burgdorferi infection can differ from the human immune response to this organism. Furthermore, not all disease manifestations observed in humans also are observed in mice, especially the erythema migrans and neurologic symptoms typically associated with Lyme disease (74).Presently, the rhesus macaque (Macaca mulatta) provides the closest animal model to human Lyme disease. Infection of these animals with B. burgdorferi results in an almost complete spectrum of human disease and the various ...