Selection and identification of antigenic determinant of Mycobacterium tuberculosis H37Ra strain

A new procedure for the selection of the antigenic determinant of Mycobacterium tuberculosis H37Ra strain is described. The bacterium components destroyed by ultrasonic were isolated by 15% SDS-PAGE, transferred onto nitrocellulose membrane, immunostained with McAbs against H37Ra. One McAb-positive fragment was obtained using the Western blot analysis. The molecular weight of the antigenic determinant is 35,000 dalton. The antigenic determinant is of immunological reactivity with McAb and TB patients' sera in dot-immunoassay and demonstrated in delayed skin tests in guinea pigs. The amino acid composition of the antigenic determinant was analysed. These suggest that the Western blot analysis may be a useful tool for the analysis of the antigenic determinant.