Expression of functional hypodermin A, a serine protease from Hypoderma lineatum (Diptera, Oestridae), in Schneider 2 cells.

Hypodermin A (HA) is a serine protease secreted by first-instar Hypoderma lineatum larvae (Oestridae, Diptera). It plays a crucial role in induced immunosuppression during hypodermosis. This report describes the production of recombinant HA in Drosophila melanogaster Schneider 2 cells, its purification and its characterization, and compares it with the protease extracted form parasite larvae. The recombinant protein and the native HA have similar biochemical and biological features. Activity of the recombinant protease on the lymphocyte proliferation inhibition and on membrane antigen cleavage was tested and shown to be similar to the native one. Tunicamycin treatment of the recombinant HA shows that the two putative glycosylation sites carry glycan residues. Unglycosylated recombinant HA has the same enzymatic activity as the fully glycosylated protein, indicating that glycosylation is not important for the protease activity of HA.