Cellular and humoral local immune responses in sheep experimentally infected with Oestrus ovis (Diptera: Oestridae)Guillaume Tabouret, Caroline Lacroux, Olivier Andreoletti, Jean Paul Bergeaud, Yacob Hailu-Tolosa, Hervé Hoste, Françoise Prevot, Christelle Grisez, Philippe Dorchies and Philippe Jacquiet
UMR 959 INRA/DGER de Physiopathologie Infectieuse et Parasitaire des Ruminants, École Nationale Vétérinaire, 23 chemin des Capelles, 31076 Toulouse, France
(Received 28 May 2002; accepted 12 November 2002)
Cellular and humoral local responses were investigated following repetitive artificial Oestrus ovis infections in lambs. The presence of larvae induced a huge local recruitment of either leucocytes (T and B lymphocytes, macrophages) or granulocytes (eosinophils, mast cells and globule leucocytes). This cellular response was more pronounced in the ethmoid and sinus (development sites of second and third instar larvae) than in the septum or turbinates where first instar larvae migrate. Infected lambs produced Oestrus ovis specific IgG and IgA antibodies in their mucus. This local humoral response was mainly directed against larval salivary gland antigens and not against larval digestive tract antigens. Compared to the control animals, the sinusal mucosa of infected animals was extremely thickened and the epithelium exhibited hyperplasia, metaplasia and eosinophilic exocytosis. The possible roles of these local immune responses in the regulation of O. ovis larvae populations in sheep are discussed.
Key words: Oestrus ovis / local immune response / lymphocyte / eosinophil / IgA and IgG immunoglobulins
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© INRA, EDP Sciences 2003