A MOUSE MODEL FOR LATENT TUBERCULOSIS

The aim of the study mas to establish a reproducible murine model for latent tuberculosis. We propose an operational definition of latent mu rine tuberculosis as a stable Mycobacterium tuberculosis count in lung s and spleens without clinical signs or obvious histopathological chan ges in the lungs over a long period of time and without spontaneous re activation of disease. B6D2F1Bom mice mere inoculated with a wide rang e of Mycobacterium tuberculosis doses intraperitoneally or intravenous ly and followed for a long period to determine suitable conditions to produce latent infection. No anti-tuberculosis drug treatment mas used . Microbiological and histopathological studies mere carried out, Cort icosterone challenge was used to reactivate the latent infection. Mice infected with 4 x 10(4) and 4 x 10(5) bacilli i,p. were followed up t o 107 weeks without spontaneous reactivation. The present model is dis cussed in comparison with previous latent tuberculosis mouse models as well as the possible mechanisms of shift to stationary phase from mul tiplying bacilli.