title: Ultrastructural study of porcine alveolar macrophages infected in vitro with porcine reproductive and respiratory syndrome (PRRS) virus, with and without Haemophilus parasuis.
abstract: Two experiments were designed to study ultrastructural changes in porcine alveolar macrophages (PAM) inoculated with porcine reproductive and respiratory syndrome (PRRS) virus (experiment 1) and with PRRS virus and Haemophilus parasuis (experiment 2). In both experiments, the viral infectious dose represented a "multiplicity of infection" of 1. Viral infection alone induced minimal ultrastructural changes at this dose, consisting only of an increase in lysosome numbers. Mixed viral and bacterial infection induced the production of greatly increased numbers of phagosomes and phagolysosomes. The PAM were of low efficacy in phagocytizing H. parasuis. PRRS virus infection had only a minimal effect on the phagocytosis of H. parasuis by PAM. It is suggested that the virus induces PAM activation rather than PAM destruction.
authors.affiliation: Departament de Patologia i Producció Animals, U.D. Anatomia Patològica, Facultat de Veterinària, Universitat Autònoma de Barcelona, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Segalés
authors.forename: M
authors.initials: M
authors.lastname: Domingo
authors.forename: M
authors.initials: M
authors.lastname: Balasch
authors.forename: G I
authors.initials: GI
authors.lastname: Solano
authors.forename: C
authors.initials: C
authors.lastname: Pijoan
mesh_terms: D000367:Age Factors; D000818:Animals; D002478:Cells, Cultured; D006190:Haemophilus / Q000502:physiology*; D008262:Macrophage Activation; D016676:Macrophages, Alveolar / Q000382:microbiology* / Q000473:pathology / Q000648:ultrastructure* / Q000821:virology; D008854:Microscopy, Electron; D010587:Phagocytosis; D019316:Porcine respiratory and reproductive syndrome virus / Q000502:physiology*; D013552:Swine; D013997:Time Factors