EFFECTS OF BASEMENT-MEMBRANES ON THE BEHAVIOR OF HEMOCYTES FROM PSEUDOPLUSIA-INCLUDENS (LEPIDOPTERA-NOCTUIDAE) - DEVELOPMENT OF AN IN-VITROENCAPSULATION ASSAY

The effects of culturing hemocytes from Pseudoplusia includens on the basement membrane preparation, Matrigel, were examined. Hemocytes in m ixed populations did not spread on tissue culture plates coated with M atrigel, whereas cells readily spread on uncoated plates. The two adhe sive morphotypes, granular cells and plasmatocytes, also failed to spr ead when purified and cultured on Matrigel coated plates, although pla smatocytes formed homotypic aggregates. Granular cells cultured on Mat rigel retained their ability to endocytose fluorescently labeled beads and to adhere to a variety of foreign surfaces. Mixed populations of hemocytes or purified populations of plasmatocytes readily encapsulate d Dowex 1X2 beads when incubated on Matrigel coated plates. In contras t, individual beads were not encapsulated when hemocytes were cultured with Dowex 1X2 beads in uncoated tissue culture plates. Capsules form ed in vitro on Matrigel were indistinguishable from capsules formed in vivo, suggesting this simple system will be valuable in characterizin g factors mediating encapsulation in insects.