Open AccessEntry and Elimination of Marine Mammal Brucella spp. by Hooded Seal (Cystophora cristata) Alveolar Macrophages In Vitro
Author(s) -
Anett Kristin Larsen,
Ingebjørg Heleymo,
Preben Boysen,
Morten Tryland,
Jacques Godfroid
Publication year - 2013
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0070186
Subject(s) - marine mammal , biology , brucella , bronchoalveolar lavage , harbor seal , porpoise , alveolar macrophage , microbiology and biotechnology , phoca , macrophage , pathology , in vitro , immunology , lung , brucellosis , zoology , medicine , fishery , biochemistry , harbour , computer science , programming language
A high prevalence ofBrucellapinnipedialisserology and bacteriology positive animals has been found in the Northeast Atlantic stock of hooded seal (Cystophoracristata ); however no associated gross pathological changes have been identified. Marine mammal brucellae have previously displayed different infection patterns in human and murine macrophages. To investigate if marine mammal Brucella spp. are able to invade and multiply in cells originating from a presumed host species, we infected alveolar macrophages from hooded seal with aB. pinnipedialishooded seal isolate. Hooded seal alveolar macrophages were also challenged withB. pinnipedialisreference strain (NCTC 12890) from harbor seal (Phocavitulina ),B. cetireference strain (NCTC 12891) from harbor porpoise (Phocoenaphocoena ) and aB. cetiAtlantic white-sided dolphin (Lagenorhynchusacutus ) isolate (M83/07/1), to evaluate possible species-specific differences. Brucella suis 1330 was included as a positive control. Alveolar macrophages were obtained by post mortem bronchoalveolar lavage of euthanized hooded seals. Phenotyping of cells in the lavage fluid was executed by flow cytometry using the surface markers CD14 and CD18. Cultured lavage cells were identified as alveolar macrophages based on morphology, expression of surface markers and phagocytic ability. Alveolar macrophages were challenged with Brucella spp. in a gentamicin protection assay. Following infection, cell lysates from different time points were plated and evaluated quantitatively for colony forming units. Intracellular presence ofB. pinnipedialishooded seal isolate was verified by immunocytochemistry. Our results show that the marine mammal brucellae were able to enter hooded seal alveolar macrophages; however, they did not multiply intracellularly and were eliminated within 48 hours, to the contrary of B. suis that showed the classical pattern of a pathogenic strain. In conclusion, none of the four marine mammal strains tested were able to establish a persistent infection in primary alveolar macrophages from hooded seal.