APPLICATION OF A MONOCLONAL-ANTIBODY RECOGNIZING PROTEIN P-30 TO DETECT AFRICAN SWINE FEVER VIRUS-INFECTED CELLS IN PERIPHERAL-BLOOD

Monoclonal antibody (MAb) 174F11.8 recognizes an epitope of the Africa n swine fever (ASF) virus-induced protein, p30, a protein expressed on the plasma membrane of infected cells. This MAb has been used to anal yze infected cell populations in peripheral blood of experimentally in oculated pigs with a virulent or attenuated ASF virus. Flow cytometric analysis of peripheral blood at different days postinfection using th is MAb, showed expression of p30 mainly in the monocyte/macrophage cel l lineage. Additionally, a small percentage of granulocytes also expre ssed p30 during infection. This methodology allowed the quantification of fluctuations in the pool of infected monocyte/macrophage cells in the inoculated pigs, maximum percentages ranging between 6 and 31%. Si gnificant differences in the percentages of cell populations expressin g p30 were not found between virulent or attenuated virus infection. H owever, a 2- to 4-day delay in the maximum percentage of cells express ing p30 was observed during infection with the attenuated virus when c ompared to virulent virus infection. Percentages of infected cells det ected by the expression of p30 and viral titres obtained in peripheral blood showed positive correlation. Consequently, MAb 174F11.8 constit utes a marker to follow evolution of ASF virus infection, allowing qua ntification of percentages of infected cells in peripheral blood.