TABLE 2.

OspB phenotype, plasmid content, transformability, and infectivity of B31 MI and clonal derivatives

StrainOspB phenotypePlasmid(s) lostTransformation resultInfectivity in micea
Shuttle vectorAllelic exchangebNo. of mouse sera reactive with P39/total no.No. of culture-positive mice/total no.c
B31 MIHeterogenousNone++3/33/3
A1Truncatedcp9, lp28-1++3/3, 3/30/3, 0/3
A2Truncatedcp9, lp25dNAeNANANA
A3Truncatedcp9++3/33/3
B1Full lengthlp28-4+3/33/3
B2Full lengthlp21, lp25, lp28-1/-4NANANANA
B3Full lengthlp28-4NANANANA
C1Full lengthlp5, lp28-4, cp32-3/-9+3/33/3
C2Full lengthlp5, lp25, lp28-1/-4, cp32-3/-9NANANANA
MI-ΔoppAII-7.3Truncatedlp5, cp9, lp25NA+0/30/3
MI-ΔoppAII-44Truncatedlp5, cp9NA+0/30/3
MI-ΔchbC-37Truncatedlp5, cp9NA+3/30/3
  • a After needle inoculation.

  • b Electroporation or TSS transformation with allelic-exchange constructs oppAII::kan, chbC::gent, or rpoS::kan as described in the text; transformation frequencies were between 10−9 and 10−8 and independent of the construct or transformation method.

  • c Growth of spirochetes in cultures of skin, joints, and bladder in BSK-II medium. Cultures were considered negative when no spirochetes could be detected by 6 weeks after tissue inoculation.

  • d PCR with the lp25-specific primer pair resulted in a faint product of the expected size. However, Southern blot analysis with an lp25-specific probe did not result in a detectable band (Fig. 4).

  • e NA, not addressed.