3D co-cultures of epithelial cells with immune cells as a model of HSV and oncolytic HSV infections

Virus infectivity is commonly investigated with in vitro monolayer cell cultures or in vivo animal models. Ease of growth and manipulation and low cost characterise standard cell culture. Animal models allow investigation of infectivity in the context of tissue structure and environment but are costly and can be limited by species variations. Neither approach can recapitulate the human context, the tissue microenvironment and human immune components. Three-dimensional organotypic raft tissue models can provide most of the advantages of in vitro and in vivo models.

We successfully established HSV and oncolytic HSV (HSV1716) infection in 3D raft cultures of epithelial non-tumour (HaCaT) and tumour (SiHa, OVCAR3 and TOV21G) cell lines. Our 3D models allowed the evaluation and quantification of virus replication and the recovery of the virus both in culture media and tissues.

We developed a complex 3D co-culture of epithelial cells with human immune cells in order to mimic the tissue microenvironment. This innovation allowed us to study the effect of immune cells in cell killing by HSV1716 in the in vitro tissues. In HSV1716-infected co-culture tissues, immune cells were identified throughout the tissue and some migrated to the areas of infection. The immune activity was identified through increased IL-8 release. Moreover, combining infection with immune cell infiltration increased tumour cell killing in the 3D co-culture model. This new co-culture model could be further developed to identify the role of immune cells in oncolytic viroimmunotherapy and to dissect the involvement of specific single immune cell subpopulations.