[Associated synthesis of some secreted pathogenicity factors of Klebsiella pneumoniae].

The study was carried out to evaluate the substrate specificity and activity of proteases secreted by strains of Klebsiella pneumoniae with various degree of virulence. The process included cultivation of the strains in semi-synthetic medium, after which the biomass was inactivated and the supernatant was separated from bacterial cells through centrifugation. Elastase-, trypsin-, and chymotrypsin-like proteolytic activity was measured in the supernatant and in all fractions obtained through gel-filtration, followed by DEAE-sepharose purification.

[Protease activity of Klebsiella pneumoniae of different virulence].

The study of substrate specificity and activity of proteolytic enzymes secreted by K. pneumoniae strains with different virulence was carried out. The strains were cultivated in a liquid semi-synthetic medium.

Immunotoxicological characteristics of preparations based on carcinoembryonic antigen and mucin containing CA 125 antigen.

Experiments on male hybrid mice demonstrated that specific immunotherapy with preparations based on carcinoembryonal antigen and mucin containing CA 125 antigen was not associated with general toxicity, local irritating effect, and hepatorenal dysfunction. The absence of toxicity is apparently due to the fact that antigens injected intramuscularly or subcutaneously virtually do not enter the blood. Injections of preparations based on carcinoembryonal antigen and mucin containing CA 125 antigen to mice induced a standard immune response with predominance of class M immunoglobulins during the early terms and class G immunoglobulins at later terms.

Antitumor activity of specific immunotherapy with mucin containing CA 125 antigen in mice with CaO 1 ovarian carcinoma.

Experiments in CBA mice with transplanted CaO 1 ovarian carcinoma possessing common antigenic determinants with human ovarian carcinoma showed that specific immunotherapy with mucin containing CA 125 antigen inhibited tumor growth by 60% and prolonged animal lifespan by 40-60% in comparison with the control. The correlation coefficient between the tumor size and antibody titer after injection of mucin was -0.4 for IgM and -0.

[Production of biologically active recombinant ricin B-chain].

Escherichia coli cells transformed with plasmids containing ricin B-chain coding sequences are shown to express this heterologous protein in inclusion bodies. After denaturation and renaturation of the product in the presence of glutathione and lactose, the recombinant ricin B-chain is soluble, biologically active and stable. Cytotoxicity of heterodimer containing this protein and ricin A-chain is found to be only ten times lower, than that of native ricin.

[Chimeric toxin of the A-subunit of viscumin and the B-subunit of ricin].

A chimeric toxic protein was prepared from the mistletoe lectin I A-chain and ricin B-chain by using the disulfide exchange reaction. Ricin and chimeric protein were indistinguishable in binding to immobilized asialofetuin in ELISA. The chimeric protein was more toxic for Jurkat cells than native mistletoe lectin I, but not as effective as native ricin.

Renaturated ricin toxin B chain made in Escherichia coli is soluble, stable, and biologically active.

Escherichia coli cells transformed with plasmids containing ricin B-chain coding sequences are shown to express this heterologous protein in inclusion bodies. After denaturation and renaturation of the product in the presence of glutathione and lactose, the recombinant ricin B-chain is soluble, biologically active and stable. Cytotoxicity of heterodimer with this protein and ricin A-chain is bound to be only ten times less than of native ricin.

[Cytotoxic properties of a recombinant hybrid of the A protein of Staphylococcus aureus with a fragment of exotoxin A of Pseudomonas aeruginosa].

By gene-engineering technique a chimeric protein made up of fragments of Staphylococcus aureus protein A and . Pseudomonas aeruginosa exotoxin A has been constructed. The chimeric protein was shown to preserve features characteristic of its both constituents--it ADP-ribosylates elongation factor 2 and binds to Ig.