Oncolytic Newcastle disease virus activation of the innate immune response and priming of antitumor adaptive responses in vitro

AbstractOncolytic virus (OV) therapy is an emerging approach with the potential to redefine treatment options across a range of cancer indications and in patients who remain resistant to existing standards of care, including immuno-oncology (IO) drugs. MEDI5395, a recombinant Newcastle disease virus (NDV), engineered to express granulocyte –macrophage colony-stimulating factor (GM-CSF), exhibits potent oncolytic activity. It was hypothesized that activation of immune cells by MEDI5395, coupled with its oncolytic activity, would enhance the priming of antitumor immunity. Using MEDI5395 and recombinant NDVs encoding fluorescent report er genes, we demonstrated preferential virus uptake and non-productive infection in myeloid cells, including monocytes, macrophages, and dendritic cells (DCs). Infection resulted in immune-cell activation, with upregulation of cell surface activation markers (e.g., CD80, PD-L1, HLA-DR) and secretion of proinflammatory cytokines (IFN-α2a, IL-6, IL-8, TNF-α). Interestingly, in vitro M2-polarized macrophages were more permissive to virus infection than were M1-polarized macrophages. In a co-culture system, infected myeloid cells were effective virus vectors and mediated the transfer of infectio us NDV particles to tumor cells, resulting in cell death. Furthermore, NDV-infected DCs stimulated greater proliferation of allogeneic T cells than uninfected DCs. Antigens released after NDV-induced tumor cell lysis were cross-presented by DCs and drove a...
Source: Cancer Immunology, Immunotherapy - Category: Cancer & Oncology Source Type: research