| dc.description.abstract | The Coronaviridae family consists of RNA viruses within the order Nidovirales. The family is
classified into two genera, namely the corona- and toroviruses. Coronaviruses are enveloped,
single stranded, positive sense RNA viruses with genomes ranging between 27-32kb in size. The
5’ two-thirds of the genome encodes for the 1a/b polyprotein, while the 3’ one-third of the
genome encodes for the structural proteins that mediate viral entry into the host cell. These
structural proteins include the spike (S), envelope (E), membrane (M) and nucleocapsid (N)
proteins.
The nucleocapsid protein is expressed at high levels within an infected cell. Studies have shown
that this protein plays a key regulatory role in different cellular pathways, including the
inhibition of interferon production and the up-regulation of the AP1 signal transduction pathway,
amongst others. Also, the N protein is vital in the formation of the ribonucleocapsid core by
binding to the viral RNA during virion assembly. The focus of this study is the immune response
in whole blood cultures to the presence of human coronavirus (HCoV) NL63 N protein.
To characterise the stimulation of the immune activity against HCoV-NL63 N in blood
cultures, the HCoV-NL63 N gene was expressed in a bacterial system. In this pilot study, GSTtagged
N constructs were then purified and used to treat whole blood cultures from three
volunteers. ELISAs were used to measure the cytokine response in these treated whole blood
cultures. Results showed that the nucleocapsid protein has an inflammatory response on whole
blood cultures. These results have generated vital information in the potential function of the
HCoV-NL63 N protein on the immune system. It is suffice to say that the HCoV-NL63 N
protein is able to elicit an effective inflammatory response within the host cell. Future studies into the cellular pathways affected by the HCoV-NL63 N protein will clarify its exact role in
stimulating the host immune system. | en_US |
