Lawrence_1993_Internat.J.Parasitol_23_309

The development of the gastrointestinal nematode Heligmosomoides polygyrus was studied in the mouse. Levels of production of acetylcholinesterase and proteases were measured in excretory/secretory products of various stages of the parasite. The production of acetylcholinesterase was found to be maximal between days 4 and 6 post-infection, corresponding to the fourth larval stage of the parasite's life-cycle. Analysis of proteolytic activity revealed both quantitative and qualitative differences between the stages. Quantitative examination showed a maximal concentration of proteolytic enzymes in the early third larval stage (L3). Qualitative analysis revealed L3-associated molecules at 96, 15 and 8 kDa, L4-associated molecules at 58 and 33 kDa and adult-associated molecules at 116, 102, 39 and 25 kDa. A number appeared to be shared by all stages (18, 16 and 13 kDa), whilst others (76 and 42 kDa) appeared to be associated with the late L4/early adult parasite. The biological and immunological implications of variation in the production of proteases and acetylcholinesterase during the development of H. polygyrus are discussed.