title: Association of Streptococcus equi with equine monocytes.
abstract: Streptococcus equi (Se), the cause of equine strangles, is highly resistant to phagocytosis by neutrophils and is usually classified as an extracellular pathogen. Large numbers of the organism in tonsillar tissues during the acute phase of the disease are completely eliminated during convalescence by mechanisms not yet understood. In this study we demonstrate in an opsono-bactericidal assay and by cytometry and confocal microscopy that Se is interiorized and killed by equine blood monocytes. This finding supports the hypotheses that adaptive immune clearance is mediated by tonsillar macrophages and that macrophages monocytes could serve as a vehicle for transport from the tonsil to local lymph nodes.
authors.affiliation: Gluck Equine Research Center, University of Kentucky, Lexington, KY 40546, USA.
authors.forename: Catherine
authors.initials: C
authors.lastname: Mérant
authors.forename: Abhineet
authors.initials: A
authors.lastname: Sheoran
authors.forename: John F
authors.initials: JF
authors.lastname: Timoney
mesh_terms: D056704:Adaptive Immunity; D000818:Animals; D001770:Blood Bactericidal Activity; D005434:Flow Cytometry; D006734:Horse Diseases / Q000276:immunology / Q000382:microbiology*; D006736:Horses; D008199:Lymphadenitis / Q000276:immunology / Q000382:microbiology / Q000662:veterinary; D018613:Microscopy, Confocal; D009000:Monocytes / Q000276:immunology / Q000382:microbiology*; D014066:Palatine Tonsil / Q000276:immunology / Q000382:microbiology; D010587:Phagocytosis; D013290:Streptococcal Infections / Q000276:immunology / Q000382:microbiology / Q000662:veterinary*; D018502:Streptococcus equi / Q000276:immunology / Q000472:pathogenicity