Immunological destruction of herpes simplex virus I infected cells

THERE are clearly two levels at which the immune response may intervene to induce protection against viral infection. Neutralising antibodies effectively limit spread of free virus in many situations, thus preventing reinfection. In a number of viral diseases, however, it is often not possible to cure the infection by even high titres of neutralising antibodies^1,2. In such situations, recovery from infection may require the intervention of a cell-mediated immune response directed at the infected cell. Selective impairment of the host's immunity, for example, by thymectomy or by antilymphocyte serum, markedly increased mortality of mice infected with ectromelia³, and herpes simplex^4,5. Macrophage suppression has had a similar effect⁶. In these cases recovery could be conferred by transfer of immune lymphoid cells (ref. 7 and B.R-Z., and A. C. Allison, unpublished). But the nature of the cells involved, and the mechanisms by which they act remain problematic. Our experiments were undertaken to evaluate the contribution of various types of cells to immune reactivity to cells infected with herpes simplex virus I in vitro.