Kinetics and Cross-Species Comparisons of Host Antibody Responses to Lone Star Ticks and American Dog Ticks (Acari: Ixodidae)

Understanding of the animal antibody response to tick salivary gland proteins is necessary to identify candidate antibodies that may have use as species- and feeding-duration-specific biomarkers of tick exposure in humans. The kinetics of the humoral immune response of rabbits to challenge feeding by 2 tick species [Amblyomma americanum (L.) and Dermacentor variabilis (Say)] was characterized by both enzyme-linked immunosorbent assay and immunoblot. Western blot analysis revealed that rabbits produced antibodies against both A. americanum and D. variabilis tick salivary gland antigens, with molecular weights ranging from 12.2 to 125 kDa; the antibody response against the saliva of both tick species possessed both unique and common aspects. The presence of antibody against low-molecular-mass (<20 kDa) salivary gland antigens of A. americanum may be specific for A. americanum exposure. Antibodies directed against D. variabilis salivary gland antigens of 111, 86.3, and 85 kDa may be specific for D. variabilis exposure. The data suggest that host antibodies directed against specific tick salivary gland proteins might have use as species-specific biologic markers of tick exposure.