Author
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Lynn, Dwight |
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Submitted to: In Vitro Cellular and Developmental Biology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 3/1/2006 Publication Date: 5/1/2006 Citation: Lynn, D.E. 2006. Lepidopteran cell lines after long-term culture in alternative media: comparison of growth rates and baculovirus replication. In Vitro Cellular and Developmental Biology. 42:149-152. Interpretive Summary: Insect viruses are potential alternatives to chemical pesticides for control of agricultural pests. However, their production requires a living host cell, which can be living insects or cell cultures. Maintaining insect colonies for this purpose is labor intensive and is a technology that does not readily lend itself to scale up for mass production of the pathogens. Alternatively, insect cells can be maintained in culture for long periods and can be more easily adapted to large-scale production systems but few previous studies have determined what, if any, effect long-term culture has on the capability of the cells to produce viruses. This study tests one aspect of this issue, the effects of long-term culture on different growth medium. Three unique cell lines were maintained for 1 to 10 years on one of two media and then analyzed for their ability to grow insect viruses. The results suggest that maintaining cells for long periods in different media can affect virus productivity, but that each cell line/virus system needs to be examined for such effects. These results will be of interest to scientists and biopesticide manufacturers in allowing them to understand factors important in using cell cultures in production systems. Technical Abstract: Three insect cell lines, IPLB-LdFB from gypsy moth fat body, IPLB-LdEIta from gypsy moth embryos, and UFL-AG-286 from velvetbean caterpillar embryos have been concurrently maintained for 1 to 10 years on two media formulations, modified TC-100 containing 9% fetal bovine serum and Ex-cell 400, a commercial serum-free medium (SFM). Cells grown in each medium were tested for susceptibility to and productivity of various multiply embedded nucleopolyhedroviruses (MNPVs). LdFB and LdEIta were tested with Lymantria dispar MNPV LdMNPV); LdEIta and AG-286 with Autographa californica MNPV (AcMNPV); and AG-286 also to Anticarsia gemmatalis MNPV (AgMNPV). The three lines chosen for these experiments fall into three categories of relative growth in SFM vs. TC-100. LdFB cells grew similarly in each medium, LdEIta grew better in Ex-Cell than in TC-100, and AG-286 grew better in TC-100 than in Ex-Cell. In addition to the disparity in growth rates between the two media for the different cell lines, The susceptibility of cells to infection also varies, although without any apparent correlation to which medium was best for supporting growth. Endpoint assays suggested that LdFB cells grown in serum-containing medium are more susceptible to virus infection than their SFM counterparts while the opposite is true for LdEIta cells. Somewhat curiously, the AG-286 cells showed no difference in susceptibility to AcMNPV in between the two media, but were more susceptible to AgMNPV in SFM. Production of virus, based on numbers of occlusion bodies, showed fewer differences with only AcMNPV production with AG-286 in TC-100 being statistically higher than production of the same virus in Ex-cell 400. These studies suggest that long-term passage in alternative media may impact the ability of cells to support virus infection and replication but the effects on each cell line and virus system need to be determined. |
