European Society of Mycobacteriology - Instituto Nacional de Saúde ...

PP-83
VIRULENCE, IMMUNOGENICITY AND PROTECTION INDUCED BY ´Mycobacterium
habana´ STRAINS IN A MURINE MODEL OF PULMONARY TUBERCULOSIS.
Montoro, Ernesto 1 ; Valdés, Iliana 1 ; Aguilar, Diana 2 ; Orozco, Hector 2 ; Hernández-Pando, Rogelio 2
1. Institute of Tropical Medicine “Pedro Kourí”(IPK), Havana, Cuba
2. National Institute of Medical Science and Nutrition ¨Salvador Zubirán¨. Mexico DF, Mexico
Mycobacterium habana’ was first isolated in Cuba by Valdivia, in 1971. Later, was demonstrated its protection capacity
against M. tuberculosis and other mycobacteria. We studied the virulence, immunogenicity and protection of 3 strains
of ‘M. habana’ using Balb/c mice. The first experiment was done to know the virulence potential of ‘M. habana’ using a
progressive pulmonary TB model. In the 2nd assay mice were vaccinated with 3 doses of bacilli. The grade of immunogenicity
was related with the induction of IFNγ by the stimulation of the main organs with antigens of M. tuberculosis. The
best doses that induced immunogenicity were used in the 3rd experiment for animal vaccination. Two months later mice
were challenged with M. tuberculosis H37Rv and Beijing genotype. All the animals infected with M. habana TMC-5135 and
IPK-337 were alive until the end of the experiment. IPK-220 strain showed about 20% of death to the seven week postinfection.
All the strains had significative differences when we compared with the control group infected with H37Rv
strain. The values of the colony forming units (CFU) were in correspondence with the survival rate. The percentage of
pneumonia was higher for ‘M. habana’ IPK-220, showing final values similar to mice infected with H37Rv strain. Due to
the virulent behaviour of ’M. habana’ IPK-220 we discharged it for the coming assays. The most important results of
the 2nd experiment were the statistical differences in the IFNγ production founded in groups vaccinated of ‘M. habana’
IPK-337 and TMC-5135 strains, respectively, with the BCG group. The lung CFU for these doses showed a decreasing
tendency with a total sterilization to the final of the experiment. Animal vaccinated with ‘M. habana’ strains and challenged
with M. tuberculosis H37Rv had the highest survival. These results are in accordance with the low percentage of
pneumonia with both stains. Nevertheless this differences was not statistical significative in comparison with BCG group.
With the Beijing challenge we observed differences between vaccination with TMC-5135 and BCG group. The lungs of
the animals that received BCG and challenged with Beijing showed more than 70% of pneumonia and a lower granuloma
area. The CFU reveals lower lung bacilli load in mice vaccinated with ‘M. habana’ strains. The final results demonstrate the
potential of ‘M. habana’ to protect against TB infection.
European Society of Mycobacteriology | 30 th Annual Congress | July 2009 | Porto - Portugal
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