Interferon γ potentiates human coronavirus OC43 infection of neuronal cells by modulation of HLA class I expression

HCN-1A, a human cerebral cortical neuron cell line, was examined for its susceptibility to human coronaviruses. The 229e strain replicated efficiently, but the OC43 strain did not replicate well, if at all. Treatment of the cells with interferonγ at 20U/ml for 48 hr markedly increased the susceptibility of the cells to infection with OC43 virus as shown by a 100-fold increase in secretion of infectious virus over a four day period as compared to untreated controls. The increased susceptibility was shown to be due to membrane expression of HLA class I by receptor-blockade with a monoclonal antibody specific for HLA molecules.