African swine fever (ASF) virus-induced plasma membrane
proteins may contribute to the protective immune response against the disease since they can be involved in the antibody-mediated lysis of infected cells. In this study we describe the regulation of ASF virus-induced plasma membrane
protein expression and its antibody induction in pigs after
viral infection by flow cytometric analysis. More than 80% of infected cells contained
viral antigens on the surface membranes at 6 hr postinfection (hpi), and the relative amount of
viral antigen expression was increased at 12 and 20 hpi. The kinetics of individual
viral protein expression on cell surfaces was studied by a collection of monospecific
antibodies directed against the six viral plasma membrane
proteins p12, p15, p16,
p23.5, p30, and p35. Most of these
proteins were expressed at 6 hpi, with the exception of p35, which was first detected at 12 hpi. The percentage of cells expressing each
antigen at different hpi was also determined. The immune response against virus-induced plasma membrane
proteins in pigs infected with an attenuated ASF virus strain was studied.
Antibodies against viral
epitopes exposed on plasma membranes reached a plateau at 20 days postinfection (dpi). The relative amount of
antibodies induced during
infection with these specificities was not directly related to the antibody titer of the sera. Sera obtained at 20 and 40 dpi contained
antibodies against most of the viral plasma membrane
proteins and were most efficient in recognition of
viral antigens exposed on the surface of infected cells at early times.