Cellular aspects of the immune response of the turbot, Scophthalmus maximus (L.)

• Main Author: Burrows, Amanda Susan
• Other Authors: School of Biological and Marine Sciences
• Format: Thesis
• Language: English
• Published: University of Plymouth 1995
• Subjects: Scophthalmus maximus; Turbot
• Online Access: http://hdl.handle.net/10026.1/1990; https://doi.org/10.24382/1414

Peripheral blood leucocytes of the turbot, Scophthalmus maximus, were characterised into 4 distinct groups following morphological, morphometric and histochemical examination. Total and differential cell counts were determined. Thrombocytes, the most abundant leucocyte type (52%), were highly mobile and encountered in several morphological forms. Granulocytes, representing 5.6% of the leucocyte population, histochemically most resembled the mammalian neutrophil. Both large and small lymphocytes (40.8%), were encountered. Monocytes were rarely observed (1.6%). Thrombocytes and monocytes were phagocytic in vitro at 12oc and 22oc, showing increased phagocytic activity at the higher temperature. The thymus was paired and consisted of a well developed outer cortex and an inner meduallary region. The spleen was bounded by a fibrous tissue capsule and contained a large volume of blood. Diffuse areas of red and white pulp, ellipsoids and melanomacrophage centres were apparent. Lymphocytes, thrombocytes and mature erythrocytes made up the cellular components. The kidney, located beneath the vertebral column contained haemopoietic tissue throughout. Excretory tubules were evident posteriorly. Cellular elements included developing granulocytes, large and small lymphocytes and melanomacrophages. Investigation of ontogenic development of the lymphoid tissue, from 24h post-hatch to the completion of metamorphosis (Day 63) revealed thymic, splenic and kidney rudiments all present at Day 4 with the first lymphoid cells appearing in thymus and kidney by Day 8. Splenic lymphoid cells and the development of areas of white pulp were apparent by Day 28. Differentiation of the thymus had occurred and melanomacrophage centres were seen in the spleen, completing structural lymphoid development by Day 63. Critical stages of lymphoid ontogeny were correlated with easily recognisable external morphological features. A study of the kinetics of carbon clearance by the reticuloendothelial system, revealed a phagocytic capacity in the spleen, ...