Tuberculosis Induced by Droplet Nuclei Infection

Abstract

When rats, mice, hamsters, and guinea pigs were caused to inhale either human or bovine tubercle bacilli as separate cells in fine droplet nuclei, the number of initial tubercles equalled approximately the number of bacilli calculated to have been inhaled. Moreover, the initial tubercles in the eight host-parasite combinations developed to macroscopic size within 4 weeks, apparently at a highly uniform rate, but thereafter the rate and pattern of tubercle formation varied widely (1). It seems probable, therefore, that these species do not differ in their "native" or inherent resistance to the bacilli of tuberculosis. Instead, they differ in their capacity to acquire resistance to these organisms.Additional evidence to support this hypothesis is provided by the present study, which traces the sequence of tissue changes through the homogeneous stage of the response to infection in the eight host-parasite combinations to its transformation into the later, heterogeneous phases of the disease. This study demonstrates that the rate and pattern of tubercle formation in all eight hostparasite combinations are, indeed, hfghlyuniform for a time, and correspond closely to the initial stages of tubercle formation in rabbits infected by bovine tubercle bacilli (2, 3). Material and MethodsThe animals used in these experiments, and their weights, were: albino mice, 15 to 20 gln.; Syrian hamsters, 80 to I00 gin.; Long-Evans rats, 150 to 200 gin.; and short haired guinea pigs, 500 to 800 gin. Commercial diets were fed.Infections were induced by means of the Wells' apparatus and techniques, which fulfill the postulates that govern quantitative control of droplet nuclei infection (4-7). Under these conditions the number of initial tubercles has approximated liters of aerosol inhaled times

Vaccination of Guinea Pigs with DNA Encoding the Mycobacterial Antigen MPB83 Influences Pulmonary Pathology but Not Hematogenous Spread following Aerogenic Infection withMycobacterium bovis

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Progression to tuberculosis disease increases with multiple exposures

“…Another possible explanation is that repeated exposures directly influence progression. Increasing exposure (via inoculum size) has been shown to result in more extensive pathology in animals [15][16][17]; however, the role dose plays in the development of disease has not been fully elucidated. Experimental human challenges have not been done for TB, nor to our knowledge for other respiratory bacterial pathogens.…”

Adjuvant modulation of the cytokine balance in Mycobacterium tuberculosis subunit vaccines; immunity, pathology and protection

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