Author
 |
LYNN, DWIGHT |
|
Submitted to: Journal of Invertebrate Pathology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 6/22/2000 Publication Date: N/A Citation: N/A Interpretive Summary: Insect viruses can be an effective tool for controlling pest insects. Since viruses need living cells to reproduce, either insect colonies or cell cultures must be used for production. Maintaining large insect colonies utilize a method generally unfamiliar to industries that may otherwise be interested in producing the virus while currently production of the virus in cell cultures as biocontrol agents is prohibitively expensive, primarily due to the cost of the medium. One of the most expensive ingredients in many insect cell culture media is vertebrate serum. In this report, two commercially available culture media were used to maintain two insect cell lines capable of producing insect virus. The effect of long-term and short-term growth of the cells in each of two types of medium (one containing vertebrate sera and one without). Both types of cells maintained long term in serum-free produced more virus than cells in medium with serum. Also, even more virus could be produced when cells normally maintained in serum containing medium was switched to serum-free. These results suggest that serum-free media can be effective tool for producing the virus but production schemes utilizing both types of media might be most efficient for maximizing production. This information can be used by other researchers and industry to develop a protocol for producing insect virus in cell culture. Technical Abstract: Two insect cell lines that had been maintained in both serum-free (SFM) and serum containing medium (SCM) for over 5 years each were tested for their ability to replicate baculovirus. The gypsy moth cell line, IPLB-LdEita (Ld) produced similar (not statistically different) amounts of gypsy moth nucleopolyhedrovirus (LdMNPV) occlusion bodies (OBs) in the two media (ExCell 400 and TC-100 with 9% (v/v) fetal bovine serum) but produced more of the Autographa californica nucleopolyhedrovirus (AcMNPV) OBs in SFM than in SCM. When Ld cells normally grown in SCM were switched to SFM, production of OBs from both viruses improved and, after 3 passages, reached higher levels of AcMNPV production than in cells normally maintained in that medium. A fall armyworm cell line (IPLB-SF21AE; Sf) showed slightly different effects from long- and short-term passage in SFM (ExCell 400) or SCM (TMN-FH). Cells maintained in SFM produced about 20 times more AcMNPV OBs than cells maintained long-term in SCM. Sf cells switched from SFM to SCM maintained the level of production to that seen in SFM at the first passage, but quickly dropped off OB production levels to that normally seen in SCM. Alternatively, SCM-maintained Sf cells produced higher levels at the first passage in SFM and, within 5 passages in SFM reached levels found in cells maintained for long-term in this medium. Under the conditions these two cell lines were infected, the highest levels of AcMNPV OB production in Ld cells were about 5 times that of Sf cells. The results of these studies suggest a maintenance and virus production protocol can be developed with Ld cells which could improve overall efficiency of virus production. .` |
