DETECTION OF HUMAN CORONAVIRUS 229E-SPECIFIC ANTIBODIES USING RECOMBINANT FUSION PROTEINS

Human coronaviruses are known to be a common cause of respiratory infe ctions in man. However, the diagnosis of human coronavirus infections is not carried out routinely, primarily because the isolation and prop agation of these viruses in tissue culture is difficult and time consu ming. The aim of this study was to evaluate the use of recombinant, ba cterial expressed proteins in the serodiagnosis of coronavirus infecti ons. Two proteins were examined: the human coronavirus 229E nucleocaps id protein (N), expressed as a fusion protein in the vector pUR and th e coronavirus 229E surface glycoprotein (S), expressed as a fusion pro tein in the vector pROS. The recombinant proteins were used as antigen s in Western blot (WB) assays to detect the 229E-specific IgG antibodi es and the results were compared with a standard serological method, i ndirect immunofluorescence. Serum samples of 51 paediatric patients, s uffering from acute respiratory illness, and 10 adults, voluntarily in fected with human coronavirus, were tested. The serum samples of the a dult group had coronavirus-specific IgG antibodies in both test system s. In contrast, only 8/51 sera of the paediatric group were positive f or coronavirus-specific Ige by both WB and IF and 20/51 sera were posi tive by WB, but not by IF. The overall incidence of human coronavirus infections in the paediatric age group was 55% evaluated by WB analysi s and 16% evaluated by IF. This study shows that recombinant human cor onavirus 229E proteins are suitable reagents for the epidemiological s creening of coronavirus 229E infections.