Innate immune response in insects is essential to resist the infections of pathogens. The present study investigates the antiviral immune response against intracellular baculovirus infection in the desert locust, Schistocerca gregaria. The desert locust was injected with nuclear polyhedral virus isolated from Spodoptera littoralis larvae collected from cotton and maize field in Giza governorates (SlNPV). Haemolymph was perfused 24 h post injection. The hemolymph was taken from control and treated locusts to separate haemocytes from the supernatant plasma to characterize the reaction of the adult S. gregaria to the viral infection. Transmission electron microscope revealed that, infected granular plasmtocyte and prohaemocytes possessed phagocytic vacuoles. However, the haemocytes behavior against viral infections does not seem to be consistent. Conversely, the biochemical results demonstrated that the total number of protein bands of S. gregaria increased due to treatment with SlNPV 24 h post injection. Analysis of haemolymph protein pattern of control (untreated adult) of S. gregaria detected 11 protein bands and 14 protein bands in treated haemolymph pattern. Three common protein bands between untreated and treated haemolymph protein patterns (15.7, 22 and 25 kDa), one protein band (kDa) was increased in its amount percentage due to treatment course 1.4 fold times, and two common protein bands with molecular weight (22 and 25 kDa) were decreased in amount percentage due to treatment course from by 2.4 and 1.04 folds, respectively. The present study provides the basis for supplementary studies of molecular mechanisms underlying baculovirus strategies that have evolved for the suppression or evasion of the antiviral immunity in infected cells.
Key words: Immunity, nuclear polyhedrosis virus, grasshopper.