A marked difference in pathogenesis and immune response induced by different Mycobacterium tuberculosis genotypes

• Published in: Clinical and experimental immunology Vol. 133; no. 1; pp. 30 - 37
• Main Authors: LÓPEZ, B., AGUILAR, D., OROZCO, H., BURGER, M., ESPITIA, C., RITACCO, V., BARRERA, L., KREMER, K., HERNANDEZ‐PANDO, R., HUYGEN, K., VAN SOOLINGEN, D.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01.07.2003; Blackwell; Oxford University Press; Blackwell Publishing Inc
• Subjects: Animal Studies; Animals; Bacterial diseases; BCG Vaccine - administration & dosage; Biological and medical sciences; Colony-Forming Units Assay; Cytokines - analysis; Disease Susceptibility; Genome, Bacterial; Genotype; Human bacterial diseases; Infectious diseases; Lung - immunology; Lung - pathology; Medical sciences; Mice; Mice, Inbred BALB C; Models, Animal; Mycobacterium tuberculosis - genetics; Mycobacterium tuberculosis - pathogenicity; Nitric Oxide Synthase - analysis; Nitric Oxide Synthase Type II; Polymorphism, Restriction Fragment Length; Tuberculosis and atypical mycobacterial infections; Tuberculosis, Pulmonary - immunology; Tuberculosis, Pulmonary - microbiology; Tuberculosis, Pulmonary - pathology; Animal model; Lung; Mycobacterial infection; Histopathology; Bacteria; Lung disease; Immune response; Mycobacterium bovis; Respiratory disease; Rodentia; BCG; Genotype; Survival; Strain; Infection; Pathology; Vertebrata; Mammalia; Tuberculosis; Mycobacterium tuberculosis; Mouse; Mycobacteriales; Animal; Bacteriosis; Mycobacteriaceae; Actinomycetes
• ISSN: 0009-9104; 1365-2249
• DOI: 10.1046/j.1365-2249.2003.02171.x

SUMMARY In the last decade, an unprecedented genetic diversity has been disclosed among Mycobacterium tuberculosis strains found worldwide. However, well‐conserved genotypes seem to prevail in areas with high incidence of tuberculosis. As this may be related to selective advantages, such as advanced mechanisms to circumvent [M. bovis Bacille Calmette–Guerin (BCG)‐induced] host defence mechanisms, we investigated the influence of strain diversity on the course of experimental disease. Twelve M. tuberculosis strains, representing four major genotype families found worldwide today, and the laboratory strain H37Rv were each used to infect BALB/c mice by direct intratracheal injection. Compared with H37Rv, infections with Beijng strains were characterized by extensive pneumonia, early but ephemeral tumour necrosis factor‐alpha (TNF‐α) and inducible isoform of nitric oxide synthetase (iNOS) expression, and significantly higher earlier mortality. Conversely, Canetti strains induced limited pneumonia, sustained TNF‐α and iNOS expression in lungs, and almost 100% survival. Strains of the Somali and the Haarlem genotype families displayed less homogeneous, intermediate rates of survival. Previous BCG vaccination protected less effectively against infection with Beijing strains than against the H37Rv strain. In conclusion, genetically different M. tuberculosis strains evoked markedly different immunopathological events. Bacteria with the Beijing genotype, highly prevalent in Asia and the former USSR, elicited a non‐protective immune response in mice and were the most virulent. Future immunological research, particularly on candidate vaccines, should include a broad spectrum of M. tuberculosis genotypes rather than a few laboratory strains.