In a survey of 1,714 adult Ixodes pacificus ticks collected in northern California, 24 (1.4%) were found to be infected with spirochetes that reacted with an anti-Borrelia burgdorferi polyvalent conjugate in direct immunofluorescence tests. Eleven isolates of B. burgdorferi from these ticks were characterized by monoclonal antibody, polyacrylamide gel electrophoresis, and Western blot (immunoblot) analyses. Ten of the isolates had molecular and antigenic characteristics similar to those of other U.S. isolates. One strain, cloned by limiting-dilution techniques, was different from any previously reported U.S. strain, but similar to reported European strains. The cloned strain, DN127-C19-2, did not react with monoclonal antibodies to Osp A and Osp B major proteins found in most of the U.S. strains. It exhibited an abundant protein with an apparent molecular weight of 25,000.

Two major surface proteins of Borrelia burgdorferi designated as OspA and OspB have been described,' and molecular analyses of these proteins have shown differences between North American and European isolates.' With few exceptions, both the North American and European strains bind OspA monoclonal antibody (mAb) H5332, but European isolates vary in their reaction with OspA mAb H3TS. Strains that do not react with OspA mAb (H5332 or H3TS) and that possess a major protein of 20-24-kDa apparent molecular weight have been reported from Europe, but not from North America.z4 One (DN 127) of 13 strains of B. burgdorferi isolated from adult Zxodes pacificus collected primarily from Northern California differed from any previously reported North American strain, but was similar to reported strains isolated in Europe. This report describes the molecular analyses of proteins of this strain and the reaction of a mAb prepared to a major protein of the strain.The methods used, polyacrylamide gel electrophoresis (SDS-PAGE), Western blot (WB), and indirect immunofluorescence (IFA), have been described.' Monoclonal antibody for OspA (H5332 and H3TS), OspB (H6831 and HSTS), flagellin (H9724), and B. hermsii (H4825) were kindly supplied by Dr. A. Barbour. A mAb was prepared to the 25-kDa protein band of strain DN127 by excising the band from a Coomassieblue-stained SDS-PAGE gel, electroeluting, and inoculating into Balb/c mice. Hybridomas were produced by fusion of spleen cells with P3x63-Ag8.653 myeloma cells. Supernatants of a cloned hybridoma (86 DN-1) did not react with strains of Leptospira, Borrelia hermsii, or Treponema pallidum. It was necessary to wash spirochetes in 0.5% formalinized phosphate-buffered saline before fixing to slides to obtain satisfactory IFA results with 86 DN-1 mAb.The original DN-127 strain of B. burgdorferi showed only 10% of the spirochetes reacting with H5332. Limiting dilution cloning of this strain produced a clone (DN127 cl9-2) that did not react with H5332 mAb in IFA tests, reacted very weakly or not at all in WB using H5332 mAb, was negative in WB and IFA with H3TS (OspA) and two OspB (H6831 and H5TS) mAb, and reacted with H9724 (flagellin) mAb but was negative in WB and IFA with B. hermsii (H4825) mAb. SDS-PAGE analysis showed no bands in the 3 I-kDa or 34-kDa region with the cloned strain, but a major protein in the 25-kDa region (FIG. 1A). 86 DN-1 mAb reacted strongly in WB to the 25-kDa protein and, interestingly, reacted with minor protein bands in the 20-24-kDa region of other California isolates (FIG. 1B). WB performed with patients' sera have shown that some patients have antibodies that are bound to a 25-kDa protein of the DN127 cl9-2 strain.Passage in BSK I1 affected the reaction of DN127 cl 9-2 with H5332 (FIG. 2).After eight weekly passages in BSK 11, the DN127 cl9-2 strain reacted as the original noncloned DN127 strain; i.e., approximately 10% of the spirochetes reacted to mAb H5332 in IFA, a protein band of apparent 32 kDa molecular mass appeared in SDS-PAGE, and H5332 mAb was bou...

A collection of Aeromonas strains of different origins were characterized for isolates expressing the O:34 somatic antigen. Of over 200 strains tested, approximately 14% belonged to serogroup O:34 with >85% of these strains identified as A. hydrophila regardless of source. A subset of 14 A. hydrophila O:34 strains were further analyzed for a number of structural and pathogenic features. Most O:34 strains expressed similar whole-cell protein profiles with regards to minor bands, but major band differences were noted in outer membrane proteins (OMPs) migrating between the 31K and 58K region. OMP profiles could be subdivided into three distinct patterns. All O:34 strains expressed a heterogeneous O polysaccharide side chain profile in their lipopolysaccharide (LPS), although some variation in the electrophoretic migration of lower and higher molecular weight LPS bands was noted. Polyclonal antisera raised against a 45-K OMP-associated protein of one O:34 strain (AH-195) reacted in immunoblot assays with a major 43 to 46-K OMP in 11 of 14 (79%) O:34 strains tested. Most O:34 strains (69%) were found to be pathogenic in mice with LD-50 values (i.p.) of <1.0 x 10(7) CFU; pathogenicity appeared to correlate best with elevated protease activity. The collective results suggest significant differences in both structural and pathogenic properties between some members of the O:34 group originating from human and nonhuman (fish, water) sources.