The invention relates to the technical field of bioengineering, in particular to a preparation method and application of an immunodiagnosis
antigen for identifying
mycobacterium hominis infection and
mycobacterium bovis infection, and a
fusion protein LB30 is successfully constructed and prepared by using a
genetic engineering technology based on
mycobacterium bovis deletion antigens Rv2645 and Rv3120 in an RD region. The
fusion protein LB30 in the invention induces strong cellular immune response in
tuberculosis patients, and the
immunogenicity is superior to that of a single
protein. ESAT6-CFP10-IGRA (EC-IGRA) is used for detecting
tuberculosis infection of high-risk
crowds and cattle herds in the pasturing area, LB30-IGRA is used for identifying mycobacterium hominis and bovine infection, it is found that the EC-IGRA positive and LB30-IGRA negative ratio of the high-risk
crowds in the pasturing area is higher than that of common
crowds, and it is prompted that the mycobacterium bovine
infection rate in the pasturing area is higher than that of the common crowds; if EC-IGRA positive and LB30-IGRA positive cattle exist in the cattle herds, it is indicated that
mycobacterium tuberculosis infection exists in the cattle herds. The method can be used for preliminarily identifying
human type and bovine type mycobacterium infection, and is expected to be applied to epidemiological investigation of human-animal
tuberculosis infection in the later period.