EXPRESSION OF THE ICL AND HSPX GENES INDUCED DURING SURVIVAL IN THE HOST IN MYCOBACTERIUM TUBERCULOSIS W CLUSTER STRAINS

Abstract

In vitro and ex vivo models for culturing different M. tuberculosis genotypic clusters (8 W cluster strains, 3 AI cluster ones, and 1 BJ and laboratory virulent strain H37Rv) in murine peritoneal macrophages yielded results of expression of the two basic genes icl and hspX induced by M. tuberculosis entering the macrophages. The housekeeping rrs16S gene was used as reference. The polymorphism of strains of different clusters and those of one cluster was revealed from the expression of the icl and hspX genes when cultured in the medium and macrophages. It was shown that there were 3-122- and 2-514-fold increases in the expression of the icl and hspX genes when cultured in the macrophage as compared to their in vitro growth. The expression of the icl gene showed a not more than 30- fold difference between the strains. The difference in the expression of the hspX gene that is a marker of transition to dormancy was 140 times greater. A strain with hspX gene overexpression was identified in vitro and ex vitro. This strain was referred to as a W148 subcluster that was 30% of the W strains circulating in the Russian Federation. The increased MBT W cluster constitutive expression of the hspX gene included in the dormancy regulon may provide these strains some advantages for survival in the host.

Keywords

• микобактерии туберкулеза
• экспрессия генов
• макрофаги