Immunobiologic characteristics of a recombinant Listeria monocytogenes expressing Mycobacterium tuberculosis antigens

Abstract:

Abstract:［Objective］ Tuberculosis is a chronic infectious disease caused by Mycobacterium tuberculosis complex．Hence，novel vaccines against TB are urgently needed and important to the public health.［Methods］Immunobiologic characteristics of a recombinant attenuated Listeria monocytogenes strain LMΔhly::Ag85b-esat-6 was evaluated.［Results］LMΔhly::Ag85b-esat-6 had lost the hemolytic activity．It was completely cleared from the livers and spleens of mice 5 days after inoculation via intravenous route．Furthermore，the LD50 of the recombinant strain increased by 4 Logs comparing to that of the parent strain． Histopathology reveals no obvious pathological changes following administration of the recombinant strain to mice，indicating its safety．In addition，the potential protective immune response was evaluated on C57BL/6 mice via intravenous immunization route．The results indicate that the antigen delivered by the recombination LM could induce Th1 type immune response and elicit strong cytotoxic lymphocyte effect against Ag85B-ESAT-6． ［Conclusion］Thus，LMΔhly::Ag85b-esat-6 had high safety to mice，and could be used as a novel vaccines candidate for preventing tuberculosis．