The influence of arboviral infection on the susceptibility of cultured cells to immune injury in vitro.

The susceptibility of LLC-MK2 monkey kidney cells to antivirus (antibodies versus viral antigens in the plasma membrane) and anticell (antibodies versus plasma membrane antigens) immune cytolysis in vitro was observed during the course of 100 continuous subcultures of these cells. In that period, LLC-MK2 cells infected with the Group B arboviruses, Japanese encephalitis virus and dengue 2 virus, became progressively refractory to the complement-dependent antivirus immune cytolysis as measured by 51-Cr release. In addition, the LLC-MK2 cells themselves exhibited a decreasing susceptibility to immune lysis with anticell anti-body. In contrast, during the same period, similar immune cytolysis experiments with the Group A arboviruses, Sindbis virus and Eastern equine encephalitis virus, remained constant. It was observed that arboviral infection of lytic refractory LLC-MK2 cells restored their susceptability to immune cytolysis with anticell antibodies. The kinetics of this restoration were unique for both Group A and B arboviruses and exhibited a constant relationship to the viral growth curve. It was concluded that the above findings could be explained on the basis of differential membrane antigenic density coupled with changes in the properties of the plasma membrane on which subculture and arboviral infection had antagonistic effects.