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Updated: May 17, 2026
Separation and Fractionation of Culture Filtrate Proteins (CFPs) from Mycobacterium tuberculosis
Published on: July 11, 2025
Isolation ofMycobacterium Tuberculosis 31 kDa antigen protein of diagnostic interest from culture filtrate using
E R Nair1, S Banerjee, S Kumar
1Jamnalal Bajaj Tropical Disease Research Centre and Department of Biochemistry, Mahatma Gandhi, Institute of Medical Sciences, Sevagram, 442 102 Wardha, Maharashtra India.
Abstract:
Proteins secreted into the culture medium byMycobacterium tuberculosis (M. tb) are shown to be source of antigens of immunodiagnostic interest. Anin vitro released 31 kDa antigen ESAS-7F isolated fromM.tb H(37)Ra culture filtrate by salt precipitation, SDS-PAGE and cation exchange fast protein liquid chromatography (FPLC) was shown earlier to be a diagnostically important antigen fraction. In this report, we describe the isolation of ESAS-7F antigen using monospecific antibody coupled to sepharose CL-4B column. The percentage recovery of ESAS-7F antigen using affinity chromatography was approximately 8% of the total ES antigen proteins compared to 0.05% obtained by conventional purification steps using salt precipitation, SDS-PAGE and FPLC. Similar seroreactivity was observed by the antigen isolated by both the methods in indirect ELISA. Affinity chromatography helped in an increased recovery of ESAS-7F antigen and obviates the need for time consuming conventional purification steps.
