Alan G. Barbour, M.D.
University of California, Irvine

Transmission-blocking Vaccines Against Arthropod Vectors.

Several insects and ticks transmit infectious agents to humans through their saliva while they feed on the host's blood. During and after this time, these arthropods are susceptible to antibodies and other substances in the blood that are taken into the midguts of their intestinal tracts. If there is disruption of the midgut, this interferes not only with digestion by the tick but also with the passage of infectious agents as they migrate from intestinal tract to their point of exit, the salivary glands. By targeting the midgut with vaccines and other prevention strategies, we aim to interrupt transmission of infectious agents. Vaccine candidates are being identified from libraries of recombinant DNA and by fractionating midgut tissues obtained from ticks as they feed. For "proof-of-principle" we are studing the transmission of the Lyme disease agent, Borrelia burgdorferi, to and from its vector, the deer tick Ixodes scapularis, after immunization of its natural mouse reservoir, Peromyscus leucopus, with the candidate vaccines. The experimental system for this project is established in our laboratory and a field site in the northeastern United States. If successful, the study could lead to development of arthropod-targeted vaccines for other vector-borne diseases.

Contact Dr. Barbour.