A NEW, MORE SENSITIVE LYME TEST
We were successful in developing an immunoassay for the reliable diagnosis of early stage Lyme disease. Typically, the Lyme specific IgM antibody first develops within 2 to 4 weeks after the infection, peaks after 6 to 8 weeks, and then declines after 4 to 6 months of illness in most patients. Elevated IgM antibody persists in Lyme disease and does not come down to normal range. The Lyme specific IgG antibody usually occurs within 6 to 8 weeks after onset of infection, peaks after 4 to 6 months and may remain elevated indefinitely. Since the IgM antibody is the initial immune response, it makes sense to test this antibody specifically for the earliest diagnosis.
In our assay, we use an indirect ELISA assay format, in which only IgM antibodies are captured in the well and all other classes of antibodies are removed. Unlike a direct ELISA in which the antigens are immobilized on the surface of the well, an indirect ELISA refers to an assay format in which the antigens present in the test interact with the captured antibodies. It should be noted that all IgM antibodies, including Lyme disease specific and unrelated IgM antibodies, are captured in this step. When the captured IgM antibodies are exposed to the specially developed PEG-peptide conjugates we prepared, these Lyme disease specific epitope conjugates will only bind to Lyme disease specific IgM antibodies. If no Lyme disease specific IgM antibodies are present, all conjugates will be washed away and no signal can be detected. As a result, a negative result is obtained.
The indirect IgM capture ELISA test format described uses special Lyme disease specific conjugates we developed as antigens. The use of the developed conjugate antigens largely increased the sensitivity and the specificity of detecting Lyme disease specific IgM antibodies.
The patented principals of the Lyme test system developed will also allow development of highly sensitive and specific immunoassays for many difficult to diagnose diseases including more sensitive test systems for cancer antigens. The reader is welcomed to write or call for additional details.