Human coronaviruses are known to be a common cause of
respiratory infections in man. However, the diagnosis of human
coronavirus infections is not carried out routinely, primarily because the isolation and propagation of these viruses in tissue culture is difficult and time consuming. The aim of this study was to evaluate the use of recombinant, bacterial expressed
proteins in the serodiagnosis of
coronavirus infections. Two
proteins were examined: the human coronavirus 229E
nucleocapsid protein (N), expressed as a fusion
protein in the vector pUR and the coronavirus 229E
surface glycoprotein (S), expressed as a fusion
protein in the vector pROS. The
recombinant proteins were used as
antigens in Western blot (WB) assays to detect the 229E-specific
IgG antibodies and the results were compared with a standard serological method, indirect immunofluorescence. Serum samples of 51 paediatric patients, suffering from acute respiratory illness, and 10 adults, voluntarily infected with human coronavirus, were tested. The serum samples of the adult group had coronavirus-specific
IgG antibodies in both test systems. In contrast, only 8/51 sera of the paediatric group were positive for coronavirus-specific
IgG by both WB and IF and 20/51 sera were positive by WB, but not by IF. The overall incidence of human
coronavirus infections in the paediatric age group was 55% evaluated by WB analysis and 16% evaluated by IF. This study shows that recombinant human coronavirus 229E
proteins are suitable
reagents for the epidemiological screening of coronavirus 229E
infections.