Available online at www.sciencedirect.com Journal of Virological Methods 147 (2008) 364–367 Short communication Production of rotavirus-like particles in Spodoptera frugiperda larvae P. Molinari, A. Peralta, O. Taboga ∗ Instituto de Biotecnolog´ ıa, CICVyA, INTA Castelar, CC25 (1712), Buenos Aires, Argentina Received 10 May 2007; received in revised form 3 September 2007; accepted 5 September 2007 Available online 22 October 2007 Abstract A strategy for the production of virus-like particles (VLPs) from simian rotavirus in larvae of the lepidopteran Spodoptera frugiperda is described. VP2 and VP6 coding sequences were co-expressed in larvae co-infected with recombinant baculovirus and these structural proteins self-assembled into VLPs that were secreted and accumulated in the haemolymph. Under electron microscopy, VLPs produced in larvae were indistinguishable from those produced in Sf9 insect cell cultures. The results showed that it is possible to obtain rotavirus VLPs in larvae reducing significantly the costs of production, making this approach an alternative for the manufacture of live rotavirus vaccines. © 2007 Elsevier B.V. All rights reserved. Keywords: Lepidopteran larvae; VLPs; Rotavirus An ideal vaccine should mimic the immunological stimu- lus given by natural infection but evoke minimal side effects. It should also be readily available, stable, inexpensive and eas- ily administered (Redmond et al., 1993). Virus-like particles (VLPs) consist of highly repetitive and ordered structures that can trigger potent humoral responses and extremely powerful cellular responses. The fact that VLPs can induce protec- tive antiviral immune responses without having the infectious and replicative capacities of the related virus represents a major advantage for the design of efficient and safe vaccines (Boisg´ erault et al., 2002). Rotavirus is the most important etiological agent of diar- rheal disease in infants and young children worldwide. Rotavirus infection results in approximately 1,000,000 deaths each year, primarily in developing countries. The need of an effective vaccine is clear and initial efforts have been focused on the development of oral, live attenuated human–animal reassor- tant rotavirus vaccines. Rotavirus also constitutes an important source of economic losses in animal production related to death, treatment costs and reduction in weight gain of affected ani- mals (Parwani et al., 1994; Garaicoechea et al., 2006). Most of bovine rotavirus vaccines are based on inactivated virus. The widespread occurrence of rotavirus antibodies in colostrum led ∗ Corresponding author. Fax: +54 11 4621 0199. E-mail address: otaboga@cnia.inta.gov.ar (O. Taboga). to strategies for maternal rotavirus vaccination to boost lacto- genic immunity and transfer passive antibodies to the neonate via colostrum and milk. The variable success of maternal rotavirus vaccines in the field is influenced by vaccine dose, strain, inactivating agent, adjuvant, route of administration, and envi- ronmental rotavirus exposure levels. The use of genetically engineered rotavirus-like particle vaccines in cows to boost anti- bodies in mammary secretions shows promise. Such subunit vaccines could possess potential advantages over existing vac- cines (Saif and Fernandez, 1996), and could also be included in combined strategies as a booster to inactivated vaccines. An alternative to live rotavirus vaccines are VLPs of different protein composition that self-assemble in insect cells infected with recombinant baculovirus expressing rotavirus structural proteins. VLPs composed of VP2 and VP6 capsid proteins administered parenterally, mucosally or intrarectally provided protection against oral challenge in mice (Madore et al., 1999; Agnello et al., 2006). One of the main conditions that VLPs must fulfill to be a potential vaccine candidate is the ability for production in an expression system safe and amenable to large-scale production. This consideration undoubtedly has an impact on public health, but is particularly significant in the case of veterinary vaccines, where the cost of a dose must be weighed against the value of the vaccinated animal. So far, recombinant rotavirus VLPs have been produced in cell culture systems (Zeng et al., 1996; Madore et al., 1999; Kim et al., 2002; Shuttleworth et al., 2005; Agnello et al., 2006). Compared with 0166-0934/$ – see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.jviromet.2007.09.002