[Contribution of L,D-carboxypeptidases in virulence of facultative intracellular pathogenic bacteria Listeria monocytogenes].

Aim: Evaluate influence of mutation of Listeria monocytogenes genes coding murein-tetrapeptide L,D-carboxypeptidase Lmo0028 and Lmo1638 on dynamics of infectious process and interaction of purified muropeptides with NOD1 receptor.

Materials And Methods: Wild type EGDe strain and recombinant strains GIMins1638 H GIMins0028 obtained on its basis by site-specific mutagenesis were used. Infectious process dynamics was studied on the model of intravenous infection of BALB/c mice. Ligand-receptor interaction activity of muropeptides isolated from recombinant and parent strains were assayed on HEK293-hNOD1 cell line expressing NOD1 receptor and containing in their genome beta-galactosidase reporter gene under the control of NF-kappaB dependent promoter expression.

Results: Lack of Lmo0028 decelerates reproduction of listerias in animal liver starting from 24 hours and at later terms after the infection whereas lack of Lmo1638 leads to increase of microbial load 6 and 24 hours after the infection with no influence on further infection. Differences in activation of NOD1 receptor by muropeptides isolated from recombinant and parent strains were not detected.

Conclusion: Despite high homology murein-tetrapeptide L,D-carboxypeptidase Lmo0028 and Lmo1638 make a different contribution to the development of infectious process caused by L. monocytogenes in BALB/c line mice. Lack of differences in NOD1 receptor activation may be associated with compensation of enzymatic functions in strains with mutation in each of the genes owing to the presence of homologous protein.