Susceptibility and Resistance to Complement-mediated Antibody Lysis in Herpes Simplex Virus-infected Cells

Abstract

<p>Herpes simplex virus-infected cell lines were tested for susceptibility or resistance to complement-mediated antibody lysis by means of the 51Cr release test. Certain human cell lines were found to be resistant to lysis. The resistance to lysis could not be correlated with the ability to produce viral progeny or the expression of viral antigens, as detectable by indirect immunofluorescence assays. Adsorption studies permitted a more precise quantitation of antigenic expression. All cell lines expressed similar quantities of antigen, and adsorbed equal amounts of antibody. Resistant cell line consumed complement, but less efficiently than did the susceptible lines. Resistance could not be related to the ability to cap, or to the phase of the growth cycle. Resistance to lysis appeared to be a property of the cell membrane, modified by the insertion of viral specific proteins after infection. Treatment of the immunoresistant cells with neuraminidase, an enzyme which, it has been suggested, non-specifically increases the immunogenicity of target cells, resulted in the reversal of resistance to lysis in all four HSV-1-infected human cell lines, and in two of the four HSV-2 infected human cell lines. Neuraminidase did not act by unmasking viral antigens, as has been previously suggested, nor did it facilitate the binding of antibody to antigen. This was shown by adsorption of HSV-specific antiserum with neuraminidase-treated and untreated cells. Cells treated with neuraminidase consumed less complement than did untreated cells. This suggested that neuraminidase acted by facilating the interaction of complement with the target cell, making complement uptake more efficient.</p>