Characterization of a soluble hemagglutinin induced in African swine fever virus-infected cells.
Hemadsorption (Had) of erythrocytes to the surface of African swine fever virus (ASFV)-infected cells is a well-known phenomenon but hemagglutination of pig erythrocytes in the supernatant of ASFV-infected cells has not been reported before. We report here the discovery of a pig erythrocyte-agglutinating activity released to the in vitro cell culture medium by cells infected with some isolates of ASFV. This finding allowed the identification and characterization of a soluble hemagglutinin (HA) molecule that could be separated from the ASFV particles either by ultracentrifugation or by gel-permeation chromatography. The HA was inactivated by agents known to affect protein conformation such as heat, beta-mercaptoethanol, urea, and guanidine isothiocyanate. Glycosylation seemed to be of importance since treatment of HA with glycosidase F inhibited the hemagglutinating activity and HA could be partially purified by affinity chromatography on immobilized concanavalin A. When native it had an estimated molecular weight of 300 kDa by gel-permeation chromatography yielding 51-kDa protein monomers under denaturing conditions as identified by immunoblotting. Preliminary attempts to correlate the induced anti-HA serum antibodies with viremia or infection-inhibition serum antibodies after infection of pigs with attenuated ASFV or immunization with purified HA are also reported.
Departamento de Sanidad Animal, INIA, CISA Valdeolmos, Madrid, Spain.
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Ruíz-Gonzalvo
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JM
Coll
D000357:African Swine Fever / Q000276:immunology; D000358:African Swine Fever Virus / Q000737:chemistry* / Q000276:immunology; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D002478:Cells, Cultured; D004797:Enzyme-Linked Immunosorbent Assay; D014644:Genetic Variation; D006385:Hemagglutination Inhibition Tests; D006386:Hemagglutination Tests; D006389:Hemagglutinins, Viral / Q000737:chemistry* / Q000276:immunology / Q000302:isolation & purification; D007114:Immunization; D012995:Solubility; D013045:Species Specificity; D013552:Swine
D000914:Antibodies, Viral; D006389:Hemagglutinins, Viral