Differential analysis of bactericidal systems of blood serum with recombinant luminescent Escherichia coli and Bacillus subtilis strains.

Luminescence intensity of recombinant Escherichia coli and Bacillus subtilis strains with cloned luxCD(AB)E genes of the natural luminescent microorganism Photobacterium leiognathi was studied under the influence of 30 individual samples of human blood serum of different component composition. A relationship was found between the level of residual bioluminescence and degree of the bactericidal effect. Moreover, the inhibition of E. coli lux+ luminescence was shown to be related to activity of the complement-lysozyme system. The reaction of B. subtilis lux+ primarily depended on the presence of β-lysin in the blood serum. These data provide an experimental substantiation of a new method of differential analysis of humoral factors of nonspecific innate immunity with recombinant luminescent bacteria.