Research

The role of apoptosis in anti-viral defense in insects

       Like many viruses, baculoviruses induce apoptosis during infection of their host cells.  Our research has shown that if allowed to proceed unchecked, apoptosis can have a powerful limiting effect on virus infectivity, replication, and spread in the insect host.  We are using viruses that express enhanced green fluorescent protein (eGFP)  and the TUNEL technique, which stains apoptotic cells, to study how viral pathogenesis is affected in situations where apoptosis does or does not occur.  In addition we are also studying other mechanisms of anti-viral immunity in insects. 

       A new NIH-funded project in the lab examines apoptosis in mosquitoes infected with arboviruses.  We are examining the ability of Sindbis virus to successfully cause disseminated infection in the yellow fever mosquito, Aedes aegypti, when the levels of apoptosis are experimentally manipulated.

Spodoptera frugiperda larvae infected with a mutant of AcMNPV lacking the p35 gene and expressing eGFP.

Section from an infected Spodoptera frugiperda caterpillar showing nuclei stained with DAPI (A), expression of eGFP (B), or TUNEL staining to reveal apoptotic cells (C).

Clarke, T.E. and R.J. Clem.  2003. In vivo induction of apoptosis correlating with reduced infectivity during baculovirus infection.  J. Virol., 77:2227-2232.

Clarke, T.E. and R.J. Clem. 2002.  Lack of involvement of hemocytes in the establishment and spread of infection in Spodoptera frugiperda larvae infected with the baculovirus AcMNPV by intrahemocoelic injection. J. Gen. Virol. 83:1565-1572.