Morphological and immunohistochemical changes in splenic macrophages of pigs infected with classical swine fever

Classical swine fever (CSF) was induced in 20 pigs by inoculation with a vi rulent strain of CSF virus to determine sequential changes (2, 4, 7, 10 and 14 days post-inoculation) in the number and morphology of splenic macropha ges (red pulp and lymphoid marginal zone) and thus to assess the role of th ese cells in the pathogenesis of the disease. The first splenic cells to be infected with CSF virus were macrophages in the marginal zone followed by other macrophage populations. The initial phase of CSF was associated with an increase in splenic macrophage numbers in the marginal zone and a decrea se in the red pulp. Subsequently, the numbers in the red pulp increased. Th e study suggested that infection, mobilization and apoptosis of splenic mac rophages play an important role in the spread of CSF virus in vivo. Moreove r, the secretory changes that occurred in macrophages in the initial phase of the infection suggested that macrophages release chemical mediators capa ble of modulating pathogenesis, (C) 2001 Harcourt Publishers Ltd.