Unit 1 - Fish Blood Constituents
Granulocyte - Function

Back to Granulocytes

Granulocytes are involved in non-specific defence mechanisms, i.e. they respond to the presence of foreign material in the body but do not recognise specific antigens.  These cells migrate to parts of the body where invasion occurs and destroy the foreign particles by phagocytosis or by direct killing known as the cytotoxic response.  This process is termed the inflammatory response.

Definitions
ANTIGEN: Any agent which can elicit an immune response. Antigen may refer to an individual macromolecule or to a homogeneous or heterogeneous population of antigenic macromolecules. A given antigen usually contains a number of sites where combination with various antibodies may occur (determinants).  An antigen may be soluble (e.g. microbial toxins, extracts) or particulate.  The most effective antigens are proteins and polysaccharides. The surface of a microorganism typically consists of repeating patterns of antigens, and the classification of some groups of microorganisms is based on differences between the antigens of different strains.

INFLAMMATORY RESPONSE: The reaction of the tissues to injury or presence of any antigen characterised clinically by heat, swelling, redness and pain and pathologically by vaso-dilation, hyperaemia, accumulation of leucocytes, exudation of fluid and deposition of fibrin. This reaction is termed the inflammatory response.

PHAGOCYTOSIS: The intracellular uptake of solid particles by cells, either for nutritional purposes  (e.g. food), or in the case of phagocytes such as macrophages and granulocytes as a defence mechanism (foreign bodies).