| 摘要 |
The currently used method for immunological diagnosis of tuberculosis infection, the tuberculin skin test, is problematic for a number of reasons; it has low specificity in BCG vaccinated individuals, a high interobserver variance and requires skill to be read and interpreted. Furthermore it requires an extra visit to the clinic to have the test read. Both people vaccinated with BCG and those exposed to non-tuberculosis mycobacteria give a positive skin test result similar to that seen in a TB infected individual. This also applies for purified protein derivative (PPD) when used in a blood cell based test. The present invention discloses the development of an immunological TB diagnostic tool based on a combination of epitopes from proteins encoded by regions of the M. Tuberculosis (M. tub.) genome, that are not present in the BCG vaccine strain or in the most common non-tuberculosis mycobacteria. Four recently characterized proteins with this diagnostic potential were selected. Peptides from these proteins were tested one by one with peripheral blood mononuclear cells from microscopy or culture confirmed TB patients as well as from healthy BCG vaccinated controls. Some combinations of peptides showed a sensitivity level comparable to the level seen with the two wellknown M. tuberculosisspecific proteins ESAT 6 and CFP 10. An epitope combination with these peptides combined with ESAT 6 and CFP 10 gave a sensitivity of 93%, representing a raise in sensitivity of about 26-33% compared to using ESAT6 or CFP 10 alone. The results from a panel of TB patients, using a collection of the new specific epitopes clearly demonstrates, that addition of other specific epitopes to the already known specific antigens, increases the sensitivity of a diagnostic assay based on cell mediated immune response.
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