Establishment of an immortalized cell line derived from the pupal ovary of Mythimna separata (Lepidoptera: Noctuidae) and identification of the cell source.

Determining the source of primary cells is conductive to enriching sufficient cells with immortal potential thereby improving the success rate of establishing cell lines. However, most of the existing insect cell lines are established by mixing and fragmentation of explants. At present, the origin of cell lines can only be determined according to the cultured tissues, so it is impossible to determine which cell types they come from. In this study, a new cell line designated IOZCAS-Myse-1 was generated from pupal ovaries of the migratory pest Mythimna separata by explant tissues to derive adherent cultures. This paper mainly shows the further descriptive information on the origin of primary cells in the process of ovarian tissue isolation and culture. Phospho-histone H3 antibody-labeled cells with mitotic activity showed that the rapidly developing somatic cells in vivo gradually stopped proliferation when cultured ex vivo. The primary cells dissociated outside the tissue originated from the lumen cells, rather than the germ cells or the follicular epithelium cells. The results suggest that the newly established cell line IOZCAS-Myse-1 had two possible sources. One is the mutation of lumen cells in the vitellarium, and the other is the stem cells with differentiation potential in the germarium of the ovarioles. Moreover, the newly established cell line is sensitive to the infection of Autographa californica multiple nucleopolyhedrovirus, responds to 20-hydroxyecdysone and has weak encapsulation ability. Therefore, the new cell line can be a useful platform for replication of viral insecticides, screening of hormone-based insecticides and immunology research.