A study of the cytology of gastrointestinal tract of some normal and parasitised animals

Whur, Paul (1967) A study of the cytology of gastrointestinal tract of some normal and parasitised animals. PhD thesis, University of Glasgow.

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The gastrointestinal tracts of worm-free sheep and sheep infected with the nematode Ostertagia circumcinota were examined histologically to determine whether a relationship could be demonstrated between parasitic infestation and the presence of globule leucocytes. Globule leucocytes were virtually absent from the mucosa of worm-free sheep, but present in high concentrations in parasitized animals, particularly in the areas which O. circumcinota is found. These results indicated that infection by nematodes is capable of eliciting a globule leucocyte response. Rats were experimentally infected with the small-intestine nematode Nipnostrongylus brasillensis and killed at intervals over the period of infection. The gastrointestinal tracts were examined for the presence of globule leucocytes, and the results were compared with those from an uninfected control group. A marked globule leucocyte response became apparent in the small intestine on the twelfth day and persisted until the twentieth. The result demonstrated a relationship between globule leucocytes and infestation by nematodes. A further feature of these results was the apparent relationship between the appearance of globule leucocytes and the onset of the immune response (self-cure). Which resulted in the expulsion of the adult worms from the small intestine, commencing about the tenth day. The possibility that this relationship was fortuitous could not be discounted since the development of globule leucocytes may have been related to some earlier event in the life cycle of the parasite. However, the timing of self-cure can be altered by changing the immunological status of the rat. Rats were rendered hyperimmune by repeated infections with N. brasiliensis and the timing of the globule leucocyte response to a challenge infection was compared with that previously observed during a primary infestitation. The onset of the globule leucocyte response again coincided with sel-cure despite the fact that in hyperimmunerats this occurred approximately siz days earlier then in a primary infection. This result indicated a direct relationship between globule leucocytes and the immune response. Pierce and co-workers (1962, 1965) had noted globule leucocytes in the intestinal tracts of fowls during coocidial infections. In view of the possibility that other types of parasite apart from nematodes elicited a globule leucocytes response, suitable material was examined, the results suggesting that globule leucocytes are also associated with oestodes and trematodes. The possibility that Russell body cells and globule leucocytes are related (White, 1954) was investigated by comparing, with the light microscope, the morphology of experimentally produced Russell body cells were found to be morphologically similar to globule leucocytes. The ultrastructure of globule leucocytes was also described and it was noted that these cells possessed a number of features suggesting a close relationship to the Russell body cell. The nature of the immune response to N. brasiliensis has been partially resolved into antibody and anaphylactic components by other workers. It therefore became necessary to investigate the rle of globule leucocytes in anaphylaxis. Observations indicated that the globule leucocyte granule did not contain the histochemical components characteristic of mast xells and that the cellular distribution within the small intestine was distinct from that of mast cells. Globule leucocytes did not undergo degranulation during experimentally induced anaphylaxis, and it was concluded that globule leucocytes are not related to mast cells nor do they have a role in anaphylaxis. This findings provided additional indication that the role of the globule leucocyte might be as antibody producer. The globule leucocyte response was therefore examined in animals which were immunologically impaired. These were neonatally infected rats in which self-cure did not take place, and adult rats which had been neonatally thymectomised, with the cosequent abolition of self-cure. A slight globule leucocyte response occurred in neonatal rats after infection with N. brasiliensis, but because of the lack of suitable controls these findings could not be interpreted on a quantitative basis. However, in the neonatally thymectomised rats comparison with a suitable non-thymectomised control group revealed impairment of the globule leucocyte response. On the basis of the collected findings it was concluded that the globule leucocyte is a cell of the lymphoreticular series arising from a precursor which is similar or identical to a plasma cell. Such cells are directly related to the immune response towards certain nematodes and are almost certainly involved in antibody production and transport.

Item Type: Thesis (PhD)
Qualification Level: Doctoral
Additional Information: Advisers: R NC Aitken; W Mulligan
Keywords: Animal sciences, Parasitology
Date of Award: 1967
Depositing User: Enlighten Team
Unique ID: glathesis:1967-72214
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 24 May 2019 15:11
Last Modified: 24 May 2019 15:11
URI: http://theses.gla.ac.uk/id/eprint/72214

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