Oncolytic Newcastle disease virus effects on immune response - a new issue in cancer treatment

Millions of people are diagnosed with cancer each year, and fighting it puts a heavy financial burden on communities and governments. Numerous advances have been made in the field of cancer; one of the newest methods is using oncolytic viruses. This study aimed to evaluate the effect of oncolytic Newcastle disease virus wild-type strains (NDV-WTS) on the immune system.

Forty mice were divided into four groups (10 animals in each group). The control group received phosphate buffered saline, and experimental group 1 (NDV-WTS 1), experimental group 2 (NDV-WTS 2), and experimental group 3 (NDV-WTS 3) received 10-1, 10-2, and 10-3 titers of Newcastle virus on 0, 14th, and 28th days. On the 31st day, 100 µL of Newcastle virus was injected into the left footpads of animals. After 48 hours, delayed-type hypersensitivity (DTH) reactions were measured. On the 33rd day, peritoneal macrophages were isolated. Then proliferation of the cells was measured by the methyl-thiazolyl-tetrazolium (MTT) test. Neutral red uptake and respiratory burst of peritoneal macrophages were also assessed. Data were analyzed using statistical software SPSS, version 19.

The results of the DTH test showed that footpad swelling in control, NDV-WTS 1, NDV-WTS 2, and NDV-WTS 3 groups were 23.5%, 23.5%, 23.6% and 23.6%. No significant differences were seen between the groups in this regard (P > 0.05). A negative nitroblue tetrazolium (NBT) reduction test as an indicator of macrophage's respiratory burst, showed no significant difference between the groups (P > 0.05). The neutral red uptake assay and MTT test showed no significant differences between the groups (P > 0.05).

The results of this study showed that NDV-WTS in doses of 10-1, 10-2, and 10-3 have no adverse effects on healthy normal cells.