CELLS OF THE PORCINE IMMUNE SYSTEM.

The cells of the porcine immune system are very heterogeneous, both in structure and function. All of them arise from a pluripotent progenitor cell in the bone marrow, from which two different lineages are produced:  

LYMPHOID LINEAGE. The different types of porcine lymphocytes are derived from this lineage, It is responsible for the main functions that characterize the immune system, and allow the reaction against foreign molecules in a specific way, as well as memorising them against a future invasion (memory). From this line derive: 

• B LYMPHOCYTES. They are produced in the bone marrow and are responsible for the antibody secretion. Humoral Immunity.
  
  

• Different types of T LYMPHOCYTES. They are produced in the spleen and collaborate in antibody production, and in the mechanisms of the Cellular Immunity response. 

MYELOID LINEAGE. The so called accessory cells or antigen-presenting cells are derived from this lineage. Although they do not respond to specifity mechanisms, they belong to the natural or innate immunity and have an essential role in the initiation of adaptive immunity. The accessory cells can even act as effector cells in some immune mechanisms.   

• MONOCYTES and MACROPHAGES.
  
  
• GRANULOCYTES:
     
  • EOSINOPHILS.

   

  • NEUTROPHILS.
  • BASOPHILS.

   

• DENDRITIC CELLS.
  

In this chapter we shall review: porcine lymphocytes; their characteristics and functions, and the different methods now available for studying them.