Specific immune mechanism

SPECIFIC IMMUNE MECHANISM

  • Specific immunity is the specific response that is formed to antigenic stimulation. The organs involved in the specific immune response are anterior kidney, spleen, thymus, gut and gonadal lymphoid tissue.
  • The function of these organs is to indicate the type antibody for production, produce that specific antibody, then finally to destroy and remove the invasive material.

Anterior kidney

  • The anterior third of the fish kidney may be the most important haematopoietic organ. This is demonstrated by the large number of blast, undifferentiated cells, that are seen in an imprint slide. These large, light-staining cells may either be in the process of mitosis and differentiation, or awaiting the proper stimulus to become a functional, specialized cell. Among the mature forms of cells seen in kidney imprints are melanocytes which are readily identifiable by their dense granular cytoplasm. These cells may lyse and scatter dark granules of pigment throughout the intercellular spaces of the kidney. Macrophages are more numerous in the anterior kidney than in circulation of other organs of the normal fish.  
    Fish - Kidney

    Kidney of fish

Source: www.pskf.ca/sd/

Spleen

  • The spleen of fish is believed to be the main organ for the processing, storing and maturing of the erythrocytes, neutrophils and granulocytes. Small and large lymphocytes, neutrophils and granulocytes are seen in abundance in spleen imprints 
Fish - Spleen

Spleen of fish

       Source: www.pskf.ca/sd/

Thymus

  • Thymus is thought to be involved in lymphocyte stimulation and the production of specific antibody. An imprint of the thymus will show a large majority of light-staining, blast-like cells, the thymocytes, and a lesser amount of lymphocyte-like cells.
Thymus gland in fish

Location of thymus gland

 Factors influencing disease resistance and immune response of fish

General

Specific

Genetics

Individuals may exhibit difference in innate resistance and acquired immunity

Environment

Temperature, season, photoperiod

Stress

Water quality, pollution, density, handling and transport , breeding cycles

Nutrition

Feed quality and quantity, nutrient availability, use of immunostimulate, antinutritional factors in feeds

Fish

Age, species or strains, individuals

Pathogen

Exposure levels, type (parasite, bacterial, viral) virulence

Last modified: Sunday, 18 September 2011, 5:29 AM