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A single recombinant outer surface protein A (OspA) antigen designed to contain protective elements from 2 different OspA serotypes (1 and 2) is able to induce antibody responses that protect mice against infection with either Borrelia burgdorferi sensu stricto (OspA serotype-1) or Borrelia afzelii (OspA serotype-2).
Protection against infection with B burgdorferi ss strain ZS7 was demonstrated in a needle-challenge model.
Protection against B. afzelii species was shown in a tick-challenge model using feral ticks.
In both models, as little as .03 microgram of antigen, when administered in a 2-dose immunization schedule with aluminum hydroxide as adjuvant, was sufficient to provide complete protection against the species targeted.
This proof of principle study proves that knowledge of protective epitopes can be used for the rational design of effective, genetically modified vaccines requiring fewer OspA antigens and suggests that this approach may facilitate the development of an OspA vaccine for global use.
Source: Clinical Infectious Diseases, Feb 2011;52 Supple 3:s266-70. PMID: 21217174 by Livey I, O’rourke M, Traweger A, Savidis-Dacho H, Crowe BA, Barrett PN, Yang X, Dunn JJ, Luft BJ. Baxter Innovations GmbH, Biomedical Research Center, Orth an der Donau, Austria [Email: email@example.com]