Recombinant Measles virus Nucleoprotein (N) (Schwarz strain)

Availability of an individualized preselection of oncolytic viruses to be used for virotherapy of tumor patients would be of great help. Using primary liver tumor resection specimens we evaluated the precision-cut liver slice (PCLS) technology as a novel in vitro test system for characterization of paramount tumor infection parameters of individual patients. PCLS slices from resection specimens of 20 liver tumor patients were cultivated in vitro for up to 5 days and infected with 5 different oncolytic measles vaccine virus (MeV) strains. Effectiveness of tumor infection was monitored by viral nucleocapsid (N) protein detection in immunofluorescence staining or Western blot analysis or by detection of GFP marker gene expression. MeV spreading in PCLS cultures was visualized by confocal microscopy. Oncolytic MeV vaccine particles were demonstrated to efficiently infect PCLS slices originating from different primary and secondary tumors of the liver with MeV strains Moraten/Edmonston Zagreb and AIK-C showing highest infection rates (75% of all tested tumor specimens). Employing mixed liver tissue slices (exhibiting both tumorous and non-tumorous tissue, areas on one and the same sample) a distinct tumor area favouring pattern of MeV infections was observed being in accordance with our finding that primary human hepatocytes are also permissive to MeV particles, albeit at a much lower rate and with a much less pronounced cytopathic effect. Furthermore, confocal microscopy demonstrated virus penetration throughout tumor tissues into deep cell layers. In conclusion, the PCLS technology is suitable to perform a tumor-patient individualized preselection of oncolytic agents prior to clinical virotherapeutic applications.

Measles is a highly contagious human disease caused by measles virus (MeV) and remains the leading cause of death in children, particularly in developing countries. Wild-type MeV preferentially infects lymphocytes by using signaling lymphocytic activation molecule (SLAM), whose expression is restricted to hematopoietic cells, as a receptor. MeV also infects other epithelial and neuronal cells that do not express SLAM and causes pneumonia and diarrhea and, sometimes, serious symptoms such as measles encephalitis and subacute sclerosing panencephalitis. The discrepancy between the tissue tropism of MeV and the distribution of SLAM-positive cells suggests that there are unknown receptors other than SLAM for MeV. Here we identified CD147/EMMPRIN (extracellular matrix metalloproteinase inducer), a transmembrane glycoprotein, which acts as a receptor for MeV on epithelial cells. Furthermore, we found the incorporation of cyclophilin B (CypB), a cellular ligand for CD147, in MeV virions, and showed that inhibition of CypB incorporation significantly attenuated SLAM-independent infection on epithelial cells, while it had no effect on SLAM-dependent infection. To date, MeV infection was considered to be triggered by binding of its hemagglutinin (H) protein and cellular receptors. Our present study, however, indicates that MeV infection also occurs via CD147 and virion-associated CypB, independently of MeV H. Since CD147 is expressed in a variety of cells, including epithelial and neuronal cells, this molecule possibly functions as an entry receptor for MeV in SLAM-negative cells. This is the first report among members of the Mononegavirales that CD147 is used as a virus entry receptor via incorporated CypB in the virions.