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Guinea pigs prepared with various bacteria and their components to induce a necrotic reaction provoked with
1Department of Microbiology and Immunology, Kagoshima University Dental School, Japan.
Abstract:
Guinea pigs were given a preparatory injection of heat-killed Mycobacterium tuberculosis in a water-in-mineral oil emulsion into the footpads. A provocative injection of muramyldipeptide given 3-8 weeks later into the flanks, caused severe inflammation, with hemorrhage and necrosis and necrosis at the footpads. In this study, we determined the features of the preparatory injection required to prepare the necrotic reaction. Most mycobacteria-related and Gram-negative bacteria were capable of preparing guinea pigs for the necrotic reaction upon provocative injection with muramyldipeptide, whereas Gram-positive bacteria did not. Boivin- and Morrison-type lipopolysaccharides, which have a high content of bacterial protein, induced the susceptibility, whereas Westphal-type lipopolysaccharide, which has a low level of the protein, did not. Moreover, the latter adjuvant-active lipopolysaccharide and muramyldipeptide together with ovalbumin also exerted the activity. The development of delayed-type hypersensitivity to the protein antigen seemed to be important for inducing the necrotic reaction. Mice, rats, rabbits and monkeys were injected in the same way as the guinea pigs. The necrotic reaction occurred in the flanks of the monkeys, but not in the other animals. A similar necrotic reaction also occurred in the flanks of guinea pigs given live BCG cells in phosphate-buffered saline as well as the heat-killed M. tuberculosis in water-in-mineral oil emulsion upon provocative injection with muramyldipeptide. These findings suggested that the induction is associated with the development of delayed-type hypersensitivity to the protein antigen administered in the preparatory injection [corrected].
Insights
Certain bacterial components, particularly those from Gram-negative bacteria and mycobacteria, prepare guinea pigs for a necrotic reaction. This response to muramyldipeptide is linked to developing delayed-type hypersensitivity to protein antigens.
Area of Science:
- Immunology
- Microbiology
Background:
- Heat-killed Mycobacterium tuberculosis in mineral oil emulsion induces a preparatory state in guinea pigs.
- Subsequent injection of muramyldipeptide elicits severe inflammation, hemorrhage, and necrosis.
Purpose of the Study:
- To identify the specific features of the preparatory injection necessary for inducing this necrotic reaction.
- To investigate the role of bacterial components and delayed-type hypersensitivity in the observed phenomenon.
Main Methods:
- Guinea pigs received preparatory injections of various bacterial preparations (heat-killed M. tuberculosis, live BCG, lipopolysaccharides from different bacteria).
- A provocative injection of muramyldipeptide was administered 3-8 weeks later.
- Other animals (mice, rats, rabbits, monkeys) were also tested.
- Delayed-type hypersensitivity to protein antigens was assessed.
Main Results:
- Most mycobacteria-related and Gram-negative bacteria, but not Gram-positive bacteria, could prepare animals for the reaction.
- Lipopolysaccharides with high protein content (Boivin, Morrison types) induced susceptibility, unlike Westphal-type LPS.
- The necrotic reaction was observed in monkeys but not in mice, rats, or rabbits.
- Live BCG and heat-killed M. tuberculosis elicited similar reactions in guinea pigs.
Conclusions:
- The induction of the necrotic reaction is associated with the development of delayed-type hypersensitivity to protein antigens present in the preparatory injection.
- Bacterial components, particularly those from Gram-negative bacteria and mycobacteria, are crucial for preparing the immune system for this specific inflammatory response.