POINT MUTATIONS IN THE S PROTEIN CONNECT THE SIALIC-ACID BINDING-ACTIVITY WITH THE ENTEROPATHOGENICITY OF TRANSMISSIBLE GASTROENTERITIS CORONAVIRUS

Enteropathogenic transmissible gastroenteritis virus (TGEV), a porcine coronavirus, is able to agglutinate erythrocytes because of sialic ac id binding activity, Competitive inhibitors that may mask the sialic a cid binding activity can be inactivated by sialidase treatment of viri ons, Here, we show that TGEV virions with efficient hemagglutinating a ctivity were also obtained when cells were treated with sialidase prio r to infection, This method was used to analyze TGEV mutants for hemag glutinating activity, Recently, mutants with strongly reduced enteropa thogenicity that have point mutations or a deletion bf four amino acid s within residues 145 to 155 of the S protein have been described. Her e, we show that in addition to their reduced pathogenicity, these muta nts also have lost hemagglutinating activity, These results connect si alic acid binding activity with the enteropathogenicity of TGEV.