Identification of species-specific, non-cross-reactive proteins of Borrelia burgdorferi.

The low specificity of diagnostic tests for Lyme disease is due to the fact that Borrelia burgdorferi possesses many antigenic proteins that are cross-reactive with other spirochetes and bacteria. The low sensitivity is a result of high (> or = 1:100) dilutions used for patient sera during testing to eliminate non-specific cross-reactivity. The present study was conducted to identify species-specific non-cross-reactive protein(s) of B. burgdorferi that might be used as antigen(s) in serologic tests. Whole-cell sonicates of B. burgdorferi were tested against pooled sera from patients with symptoms, signs, and serologic features diagnostic of Lyme disease (LD), rheumatoid arthritis, infectious mononucleosis, systemic lupus erythematosus, Rocky Mountain spotted fever, secondary syphilis, and from healthy individuals. Different LD pools were also tested against whole-cell sonicates of Treponema pallidum, Treponema phagedenis, Leptospira interrogans, and Escherichia coli. Comparison among patterns obtained by each serum pool revealed that IgM antibodies to species-specific 39-, 23-, and 22-kD proteins and IgG antibodies to 34- and 31-kD proteins were present only in the patients with LD and absent from patients with rheumatoid arthritis, infectious mononucleosis, systemic lupus erythematosus, Rocky Mountain spotted fever, secondary syphilis, and healthy individuals pools. These results suggest that 39-, 23-, and 22-kD proteins may be used in an IgM immunoassay for diagnosis of LD.