PhD

The cellular dynamics in ducks associated with inflammatory response induced by
various immunogenic and non-immunogenic agents was studied for the first time.
The inflammatory response was induced in the web of ducks using turpentine,
dextran sulphate, talc, Staphylococcus aureus, homologus erythrocytes and
Freund’s complete adjuvant. The biopsy specimens were collected from half an hour
up to 21 days at specific time intervals and examined to assess the cellular response
and the chronology of cellular events taking place during the emigration process
was depicted. The comparative features of cellular events taking place when
different agents were employed were also clarified. The light microscopic studies
were supported by electron microscopic studies. Irrespective of the agents employed
to elicit the inflammatory reaction it was found that there was emigration of
heterophils and monocytoid cells from the arterioles and venules concurrently even
though there was quantitative difference in the number of emigrating cells due to
different agents. Initially there was high predominance of heterophils in the exudate
and later there was predominance of macrophages or lymphocytes. Participation of
basophils was also evident at the initial stages. Lymphoid foci formation with
germinal centres particularly when antigenic stimulus was used was a characteristic
feature. It was demonstrated that monocytoid mononuclear cells transformed into
macrophages, epithelioid cells and giant cells.
The morphological features of the heterophilic granules were studied by
electromicroscopy. Large dense granules with one or two electron dense core and
light granules with fibrillary matrix were seen. The process of endocytosis of the
foreign body involved fusion of phagosomes. The active heterophil was
demonstrated to contain more glycogen. The transformation of monocytoid cells
into macrophages was demonstrated to be associated with increase in size and
number of endoplasmic reticulum and formation of well developed golgi complex
and lysosomes. Epithelioid cells were devoid of phagolysosomes. It was clarified that
the lymphocytes underwent transformation into plasma cells under antigenic
stimulation. The plasmacytoid transformation was evidenced by formation of rough
surfaced endoplasmic reticulum.
The systemic response to Ranikhet disease virus and Duck plague virus was studied.
The tissue destruction and cellular response to RD virus were meagre. Heterophilic
and monocytoid cell reaction was still the initial response. In duck plague infection
there was progressive necrosis and this was associated with pronounced lymphoid
reaction indicative of an immunologic reaction. In Ranikhet disease infection the
lymphoid reaction was not as pronounced as in duck plague virus infection.