A gene bank of DNA from the
Lyme disease spirochete was constructed in the plasmid pBR322. Plasmid pTRH32, a recombinant that in Escherichia coli expresses the two major outer surface proteins of the
Lyme disease spirochete, was identified. One of the recombinant products, designated OspA, represents a surface protein that appears to be common to all
Lyme disease spirochetes, whereas the other recombinant product, designated OspB, represents a more variable surface protein. This recombinant plasmid provides a foundation for future studies on the epidemiology and pathogenesis of
Lyme disease as well as on the genetic organization of the etiologic agent.