Cloning, sequence determination, and expression of a 32-kilodalton-protein gene of Mycobacterium tuberculosis.

We describe the identification of the gene encoding an immunodominant 32-kilodalton (kDa) protein of Mycobacterium tuberculosis. The 32-kDa antigen is abundantly secreted into the culture supernatant of a variety of mycobacteria and appears to be a major stimulant of cellular and humoral immunity against mycobacteria. Recombinant clones expressing a 140- or 125-kDa beta-galactosidase fusion protein reactive with rabbit polyclonal anti-32 kDa protein serum were detected.

The production of mycobacterial antigens by homogeneous culture in a fermentor.

Mycobacterium bovis strain BCG, substrain 1173P2, has been grown in homogeneous culture in classical synthetic Sauton medium without supplementary ingredients. The culture conditions are described. The protein release in the culture medium and the tuberculin yield after 2% trichloroacetic acid precipitation were significantly improved.

A comparison of the rate of oxygen uptake and the adenosine triphosphate content of routine and experimental BCG preparations.

The ATP content and oxygen uptake rate, two parameters of viability of a BCG suspension, are compared. The lack of correlation between measurements made on fresh routine preparations indicates that the ATP measurements is affected by the degree of dispersion of the preparation. Experimental preparations made under standard conditions (constant semi-dry weight and stepwise dispersive grinding) from cultures of the same age as the fresh routine cultures (14 days) had a smaller ATP content, which correlated well with the respiration rate.