THE GENERATION AND CHARACTERIZATION OF ANTIINSECT BLOOD-CELL MONOCLONAL-ANTIBODIES

A number of monoclonal antibodies have been raised against the haemocy tes (blood cells) of two insect species: namely, the wax moth, Galleri a mellonella and a species of cockroach, Blaberus discoidalis. In the case of the wax moth, two groups of monoclonal antibodies were raised. One group, designated GM1 to GM28, identified only one type of blood cell, namely the granular cell. All 28 monoclonal antibodies recognise d a 90 kDa protein as shown by western blotting. The second group of m onoclonal antibodies, designated GallPG1 to GalIPG20, recognised all t he haemocyte types of G. mellonella, including the granular cells, pro haemocytes, plasmatocytes, spherule cells and oenocytoids. These latte r monoclonal antibodies all identified a protein of 35 kDa when tested by western blotting. All monoclonal antibodies against G. mellonella haemocytes were highly specific for wax moth haemocytes and did not cr oss-react with any other lepidopteran, orthopteran or dictyopteran hae mocytes tested. With the cockroach, B. discoidalis, there were two mai n sets of monoclonal antibodies produced against the haemocytes; howev er, none was specific for any of the three haemocyte types found in th is species, namely, the granular cells, plasmatocytes and prohaemocyte s. One group of Blaberus monoclonal antibodies, termed BlabMem1 to Bla bMem19, labelled the cell surface and cytoplasm of the plasmatocytes, prohaemocytes and granular cells. These monoclonal antibodies all reco gnised a protein of approximately 60 kDa. The second group of monoclon al antibodies, designated BlabGr1 to BlabGr31, labelled the granular i nclusions of all haemocyte types. The monoclonal antibodies against th e Blaberus haemocytes did cross-react with the blood cells of some clo sely related species of cockroach, but not with the haemocytes of any of the lepidopterans or orthopterans tested. Initial experiments showe d that exposure of Galleria haemocytes to the monoclonal antibodies sp ecific for the 90 kDa protein (GM1 to GM28), significantly reduced the ability of these cells to attach to bacteria in vitro. These results suggest that this protein plays a central role in the cellular defence reactions of insects and that these monoclonal antibodies should be e xtremely useful in further investigating its functional significance.