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United States Department of Agriculture

Agricultural Research Service

Title: Effect of Temperature Modulation and Bvg Mutation of Bordetella Bronchiseptica on Adhesion, Intracellular Survival and Cytotoxicity for Swine Alveolar Macrophages

Authors
item Brockmeier, Susan
item Register, Karen

Submitted to: Veterinary Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 16, 1999
Publication Date: N/A

Interpretive Summary: Bordetella bronchiseptica causes respiratory disease in swine, yet there are no studies examining the interaction of B. bronchiseptica with swine alveolar macrophages. Alveolar macrophages are responsible for initial protection of the respiratory tract by engulfing and killing bacteria that the animal breathes in during normal respiration. B. bronchiseptica was able to survive intracellularly in swine alveolar macrophages and was also able to kill these cells. The ability of B. bronchiseptica to kill alveolar macrophages, and its ability to survive after being engulfed, are no doubt important to escape from immune clearance mechanisms and establish infection, and could leave the pig susceptible to secondary respiratory pathogens.

Technical Abstract: Bordetella bronchiseptica causes respiratory disease in swine, yet there are no studies examining the interaction of B. bronchiseptica with swine alveolar macrophages. A swine isolate of B. bronchiseptica (MBORD846) was able to adhere to, and survive intracellularly in swine alveolar macrophages, but the relative ability of the bacteria to accomplish these functions was dependent on its phenotypic phase and culture conditions. More bacteria were seen extracellularly as well as intracellularly when MBORD846 was cultures at 23 C; however, more bacteria cultures at 37 C survived intracellularly. Similar results were seen in experiments performed with an isogenic Bvg phase-locked mutant of B. bronchiseptica (MBA4) cultures at 37 C or 23 C, indication that another temperature dependent locus in addition to bvg may play a role in adhesion and intracellular survival. B. bronchiseptica was cytotoxic for swine alveolar macrophages in a bvg dependent manner, but no evidence for the induction of apoptosis was found. The cytotoxicity of B. bronchiseptica for alveolar macrophages, and its ability to survive phagocytosis, are no doubt important to escape from immune clearance mechanisms and establish infection, and could leave the host susceptible to secondary respiratory pathogens.

Last Modified: 10/23/2014
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