The limiting factors of oncolytic virus immunotherapy and the approaches to overcome them.

Oncolytic virus (OV) immunotherapy is characterized by viruses which specifically target cancer cells and cause their cytolysis. They provide a unique and promising new tool for the eradication of cancer as they interact with and affect the tumor microenvironment (TME), vasculature, and immune system. Advancements of genetic engineering have allowed for these viruses to be armed in such a way to have enhanced targeting, strong immunomodulation properties, and an ability to modify the TME. However, there are still major limitations in their use, mostly due to difficulties in delivering the viral particles to the tumors and in ensuring that the immunomodulatory properties are able to stimulate the host immune response to mount a complete response. Using novel delivery systems and using OVs as a complementary therapy in a combinatorial treatment have shown some significant successes. In this review, we discuss the major issues and difficulties in using OVs as anti-tumor agents and some of the strategies put in place so far to overcome these limitations. KEY POINTS: • Oncolytic viruses (OVs) infect cancer cells and cause their cytolysis. • The major limitations in using OVs as anti-tumor therapy were discussed. • The potential strategies to overcome these limitations were summarized.

A new species of Diglyphus Walker (Hymenoptera, Eulophidae) from China, with morphological characterizations and molecular analysis.

Diglyphus Walker, 1844 (Hymenoptera: Eulophidae) is an economically important genus including species acting as biocontrol agents against agromyzid leafminer pests. A new species of Diglyphus, Diglyphusdifasciatus Liu, Hansson & Wan, sp. nov., was discovered during the identification of agromyzid leafminers and their associated parasitoid wasps collected from 2016 to 2022 in China, based on morphological characteristics and molecular analyses of COI, ITS2 and 28S genes. Diglyphusdifasciatus is similar to D.bimaculatus Zhu, LaSalle & Huang, distinguished by two interconnected infuscate vertical bands on the fore wing and the color of the scape. Molecular data support D.difasciatus and D.bimaculatus as two different species. The mean genetic distances between D.difasciatus and D.bimaculatus were 11.33%, 8.62%, and 0.18%, based on the COI, ITS2, and 28S genes, respectively.

A One-Step Multiplex PCR Method to Rapidly Distinguish Two Strains of Diglyphus wani (Hymenoptera: Eulophidae) Against Agromyzid Leafminers.

Hymenopteran parasitoids generally show a haplo-diploid sex determination system. Haploid males are produced from unfertilized eggs, whereas diploid females develop from fertilized eggs (arrhenotokous). In some cases, diploid females develop from unfertilized eggs (thelytokous). Diglyphus wani (Hymenoptera: Eulophidae) is a biological control agent for agromyzid leafminers and have arrhenotokous and thelytokous strains. However, the morphological characteristics of two strains of D. wani are so similar that it is difficult to accurately distinguish them based on morphology. Here, a rapid molecular identification method was developed based on the mitochondrial gene cytochrome c oxidase I (COI) and one-step multiplex PCR. Two primer combinations, PC1 (Ar-F1/Th-F1/WR2) and PC2 (Ar-F1/Th-F4/WR2), were designed and repeatedly screened to distinguish two strains simultaneously, of which two special forward primers Th-F1/Th-F4 were used for the thelytokous strain and one special forward primer Ar-F1 was used for the arrhenotokous strain. In addition, a common reverse primer, WR2, was used for both strains. The PC1 and PC2 PCR assays were effective in distinguishing the two strains at different developmental stages and field colonies. This method provides a reliable, highly sensitive, and cost-effective tool for the rapid identification of the two strains of D. wani.