Phospholipase A2 (PLA2) is an enzyme catalyzing phospholipids at sn-2 position to produce a free fatty acid, mainly arachidonic acid. PLA2 is implicated to express cellular immunity in insects. An entomopathogenic bacterium, Xenorhabdus nematophila, inhibits PLA2 to induce host immunosuppression . A preliminary work using various PLA2 antibodies indicates that hemocytes of Spodoptera exigua express an inducible PLA2 in response to bacterial infection. The inducible PLA2 reacted to secretory type of PLA2 antibody. Based on known PLA2 sequence of Drosophila melanogaster, we designed type ‡Va-secretory PLA2 degenerate primers. An RT-PCR (3`-RACE) 600 bp product and exhibited high homology with known PLA2 sequence. Following 5`-RACE resulted in a complete cDNA sequence of 1151 bp size. This sequence contains amidation site, casein kinase ‡U phosphorylation site, cAMP- and cGMP-dependent protein kinase phosphorylation site, N-glycosylation site, N-myristorylation site, protein kinase C phosphorylation site, and PLA2 histidine active site. RT-PCRs showed that the hemocyte PLA2 is specificity expressed in hemocytes and also that the PLA2 is expressed in response to bacterial infection.

Key words : PLA2, Xenorhabdus nematophila, Spodoptera exigua