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

Background: Millions of people are dia gnosed 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.Material and methods: 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, 14 th , and 28 th days.On the 31 st 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 33 rd 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.Results: 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).Conclusion: 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.