IL-2 complex treatment amplifies CD8⁺ T cell mediated immunity following herpes simplex virus-1 infection

CD8⁺ T cells play an important role in controlling numerous virus infections and some tumors and therefore several strategies have been adopted to modulate CD8⁺ T cell responses. One such approach includes treatment with IL-2 bound to a monoclonal antibody against IL-2 (IL-2 complex) which was shown to enhance CD8⁺ T cell responses and provide protection against some cancers and pathogens. This report analyses the value of IL-2 complex therapy to protect against a cutaneous virus infection as occurs with herpes simplex virus-1 (HSV-1) infection. Treatment with IL-2 complex after infection reduced virus levels and lesion severity in a zosteriform model of HSV infection in mice. Furthermore, IL-2 complex treatment expanded HSV-1-gB epitope-specific CD8⁺ T cells, IFN-γ and TNF-α producing CD8⁺ T cells as well as cells that produced more than one cytokine. In addition, IL-2 complex therapy recipients showed enhanced cytolytic activity of CD8⁺ T cells as shown by increased granzyme B expression and lytic granule release. Taken, together, these studies demonstrate that IL-2 complex therapy can be useful to boost protection against a cutaneous virus infection.