title: Isolation ofMycobacterium Tuberculosis 31 kDa antigen protein of diagnostic interest from culture filtrate using anti-ES-31 antibody by affinity chromatography.
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.
authors.affiliation: Jamnalal Bajaj Tropical Disease Research Centre and Department of Biochemistry, Mahatma Gandhi, Institute of Medical Sciences, Sevagram, 442 102 Wardha, Maharashtra India.
authors.forename: E R
authors.initials: ER
authors.lastname: Nair
authors.forename: S
authors.initials: S
authors.lastname: Banerjee
authors.forename: S
authors.initials: S
authors.lastname: Kumar
authors.forename: M V
authors.initials: MV
authors.lastname: Reddy
authors.forename: B C
authors.initials: BC
authors.lastname: Harinath
keywords: Affinity chromatography; ELISA; ESAS-7F