In the conditions of the Republic of Belarus there was created an adhesive antigen on the basis of bacterial suspension of Escherichia which were separated from culture media by means of purification and concentration on membranes UMP-300 and UMP-5 that made it possible to obtain a cleaned-up preparation the specific activity of which was in 2-4 higher that of the unpurified one. In course of the study there was developed a method of purification and concentration of adhesive Escherichia antigens with the help of membrane technology. There were obtained biologically active adhesive antigens E.coli K88, K99, F41, 987P; there were selected the ultrafiltration membranes providing the optimal selectivity and productivity of the process; there were studied the influence of some factors on the process of adhesins concentration by means of ultrafiltration method. During the experiments there was analysed the agglutinating activity of antigents prepared by different methods.

In the conditions of the Republic of Belarus there was determined the influence of nutritional medium composition on pathogenic properties of leptospirosis bacteria, by an example of 6 pathogenic strains: Leptospira pomona; Leptospira tarassovi; Leptospira grippothyphosa; Leptospira icterrohaemorragia; Leptospira conicola; Leptospira hardjo. During the study there were used the following media: serum-supplemented vitaminized medium on the basis of buck serum; serum-supplemented medium with a growth factor; serum-supplemented vitaminized medium with antlbody biosynthesis growth factor; semisynthetic Russel's medium. According to the results of realized studies there was developed a correlation between terms of leptospirosis bacteria survivability in laboratory animals depending on cultivation medium. In course of the study there were analyzed terms of Leptospira persistence in guinea pigs.

In the conditions of the Republic of Belarus there was realized creation and evaluation of growth activity of serum and albuminous nutritional media. In the experiment there were used of 6 pathogenic strains: Leptospira pomona; Leptospira tarassovi; Leptospira grippothyphosa; Leptospira icterrohaemorragia; Leptospira conicola; Leptospira sejroe. For the Leptospira cultivation there were used the following media: serum-supplemented vitaminized medium on the basis of buck serum; serum-supplemented medium with a growth factor; serum-supplemented vitaminized medium with antlbody biosynthesis growth factor; semisynthetic Russel's medium in modification of V.I. Sitkov. Research results showed that the albuminous nutritional medium provided an intensive accumulation of Leptospira of all tested serogroups of Leptospira, but was suitable only for single bacterial inoculation. For the secondary hatching the albuminous media was unsuitable as it lowered the antigenic activity of Leptospira.

In the conditions of the Republic of Belarus there was realized a cultivation of pasteurellas by different methods in Hottinger broth in 37 deg C temperature in course of 24 hours. Tissue culture properties were studied in accordance with the character of bacteria growth in liquid nutritive media and at the agar surface. Research results showed that in 7 hours after cultivation in media with application of shuttel apparatus and addition of glucose it was possible to obtain the highest quantity of viable pasteurellas with a high degree of virulence. The obtained culture on the basis of obtained results was proposed to be used for the production of virulence antigen.