Dogfish leucocytes were characterised by histochemistry, light
and electron microscopical methods and qualitative phagocytic studies.
This enabled the recognition of the major phagocytic cells and their
role in the immune response of the fish was further evaluated.
In addition to in vitro and in vivo studies of phagocytosis, the
phagocytic cells were examined for certain surface properties such as
the presence of Fe and C3
receptors. Attempts were also made to
demonstrate delayed hypersensitivity by in VIVO skin tests and in vitro
migration inhibition tests.
All the major leucocytic elements found in mammals were
demonstrated in dogfish blood together with some, as yet, unidentified
cells. The main phagocytic cells of the blood were the neutrophil
and the monocyte. Clearance of antigen and other particulate material
from the circulation was effected chiefly by the spleen and to a
lesser extent by the gill. In contrast to mammals, the liver showed
no phagocytic activity.
Although in vitro studies indicated that the identified phagocytes
were efficient at endocytosing antigenic material, in VIVO clearance
studies showed that low numbers of viable bacteria and yeasts persisted
in the circulation for long periods after injection. This suggests
a functional deficiency in the phagocytic ability of dogfish compared
to higher vertebrates. This may however be augmented by natural
elements in their circulation. Delayed hypersensitivity reactions and
possession of receptors (which may mediate cellular interactions) were
not demonstrated in fish. This may suggest a less sophisticated system
is operating in these fish compared with mammals or conversely that
these phenomena can not be demonstrated by the methods employed in this
study.
Date of Award | 1981 |
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Original language | English |
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Awarding Institution | |
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A STUDY OF THE STRUCTURE, DISTRIBUTION AND FUNCTION OF PHAGOCYTIC CELLS IN THE IMMUNE SYSTEM OF FISH
Parish, N. (Author). 1981
Student thesis: PhD