Bacterial cell extract, process for preparing same, antitumor preparation containing same, and adjuvant preparation containing same

A process for preparing a bacterial cell extract having anti-tumor activity comprising the steps of:

• (a) disrupting microorganism cells selected from the group consisting of Mycobacterium bovis, strain BCG (NIHJ) ATCC 19015, Mycobacterium tuberculosis RIMD Alyama B, Mycobacterium tuberculosis H37Ra ATCC 25177, Mycobacterium smegmatis IFO 3153 and Mycobacterium smegmatis ATCC 607, at a temperature below about 10.degree. C. in order to prepare a disrupted cell suspension comprising an aqueous extract, undisrupted cells and cell wall residue;
• (b) removing the undisrupted cells and cell wall residue from the aqueous extract at a temperature below about 10.degree. C. to produce an aqueous cell-free extract;
• (c) adding to the aqueous cell-free extract, in order to form a precipitate and based on the volume thereof, a flocculant selected from the group consisting of:
• (i) polyvalent metal salts in an amount of from 0.1-10% by weight;
• (ii) polyacrylamides and polyamines in an amount of from 0.01-1.0% by weight;
• (iii) chitosan protamine sulfate and sodium alginate in an amount of from 0.01-10% by weight;
• and
• (iv) streptomycin and salts thereof and kanamycin and salts thereof in an amount of from 0.1-10% by weight,
• (d) collecting the resulting precipitate;
• (e) suspending the collected precipitate in water or in a suitable buffer solution;
• (f) dialyzing the resulting suspension at a temperature below about 10.degree. C. to remove the flocculant contained therein;
• and
• (g) lyophilizing the dialyzed suspension.