The Immune System
The Immune System
The avian immune system has two mechanisms: Non-specific and specific. The non-specific mechanism is the inherent ways that a chicken resists disease. This includes genetic factors, body temperature, anatomic features, normal microflora, and respiratory tract cilia.
Specific immune mechanism is the acquired way a chicken fights disease. Examples are antibodies. Antibodies are produced by lymphocytes. Lymphocytes are produced in the embryonic stage in the liver, yolk sac and bone marrow. After 15 days of incubation, the cells move to the Bursa of Fibricius, until 10 weeks of age. The cells are programmed in the BF after which they are moved to the blood, spleen, cecal tonsils, bone marrow, Harderian gland and thymus. Destruction of the Bursa of Fibricius at a young age by Bursa disease or Mareks disease prevents the programming of B-Cells. As such, the chicken will not be able to produce antibodies to defend against disease or respond to vaccines.
T-Lymphocytes are produced from the same stem cells as B-Cells, and react to antigens specifically but do not produce antibodies.
The production of antibodies by the chicken itself or obtaining antibodies from another animal may allow the chicken to become immune to a disease. When a chicken produces its own antibodies after coming in contact with a foreign pathogen this is called active immunity. When the chick receives pre-made antibodies from the egg or the hen this is called passive immunity.
Specific immune mechanism is the acquired way a chicken fights disease. Examples are antibodies. Antibodies are produced by lymphocytes. Lymphocytes are produced in the embryonic stage in the liver, yolk sac and bone marrow. After 15 days of incubation, the cells move to the Bursa of Fibricius, until 10 weeks of age. The cells are programmed in the BF after which they are moved to the blood, spleen, cecal tonsils, bone marrow, Harderian gland and thymus. Destruction of the Bursa of Fibricius at a young age by Bursa disease or Mareks disease prevents the programming of B-Cells. As such, the chicken will not be able to produce antibodies to defend against disease or respond to vaccines.
T-Lymphocytes are produced from the same stem cells as B-Cells, and react to antigens specifically but do not produce antibodies.
The production of antibodies by the chicken itself or obtaining antibodies from another animal may allow the chicken to become immune to a disease. When a chicken produces its own antibodies after coming in contact with a foreign pathogen this is called active immunity. When the chick receives pre-made antibodies from the egg or the hen this is called passive immunity.
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