Cellular And Humoral Defenses Of Glossina (diptera: Glossinidae): Reactions Against Bacteria, Trypanosomes, And Experimental Implants

Abstract

Bacillus cereus was more pathogenic than Escherichia coli to Glossina morsitans morsitans (Diptera: Glossinidae) when injected into the hemocoel. Bacteria were phagocytosed by individual hemocytes, and small hemocyte clumps entrapping several bacteria were formed, but typical nodules were not observed. Injection of live E. coli caused no decrease in total hemocyte counts (THCs), while live B. cereus and E. coli endotoxin caused significant drops in THCs resulting from marked hemocyte clumping and lysis. Foreign tissues implanted into GLOSSINA became intensely melanized, but no cellular encapsulation was ever observed. Vaccination of G. m. morsitans with small doses of live E. coli conferred some protective immunity to challenge with subsequent higher doses of the same organism. Hemolymph collected from G. m. morsitans 48 h after injection with live E. coli showed an increase in 2 preexisting proteins with molecular weights of ca. 70,000 and 17,000 daltons. This increase was not observed in the hemolymph of flies inoculated with heat-killed E. coli or B. cereus, or with E. coli endotoxin, live T. b. brucei, or saline.