Photometric Approaches in the Study of Insect Immune Cells

Program year: 1996/1997Digitized from print original stored in HDRThe study of insect immunology has been hampered by the limited quantity of material from any one individual. We have developed several techniques to make use of flow cytometry for the isolation and characterization of insect haemocytes. Flow cytometry was used to sort classes of Heliothis virescens (Fabricus) cells enriched for the larger, more differentiated blood cells which were then injected into mice for the production of monoclonal antibodies. Monoclonal antibodies are of interest because they are very specific, quantitative, and when bound to an appropriate fluorescent conjugated tag, readily recognized by the flow cytometer. We have also stained haemocyte DNA using mithromycin (and other DNA stains) to show the first known description of relative DNA amounts in insect blood cells. We find the cells to be 2C, 4C, and 8C with no higher ploidy or polyteny levels. Also shown is the capacity to score phagocytic cells and show the numbers and percents of cells that engulf one or more 1 micron fluorescent beads. We feel the production of monoclonal antibodies, plus the DNA and phagocytic studies described here, will provide useful new research tools for the study of insect haemocytes