Cellular immunology / Macfarlane Burnet.

  • Frank Macfarlane Burnet
Date:
1969
Catalogue details

Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: Cellular immunology / Macfarlane Burnet. Source: Wellcome Collection.

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    Commitment of immunocytes with a given antigen an animal gives a much more active immune response. In cellular terms it now has a population of committed immunocytes. In a sense the uncommitted immunocyte is a hypo¬ thetical entity needed to account indirectly for many observational and experimental facts. Committed immunocytes are the lympho¬ cytes which can be demonstrated to respond specifically to antigen. The change from the uncommitted to the committed immunocyte can be most readily and probably correctly pictured as involving an increase in the number of specific immune receptors (which may now be in the form of Ig M antibody molecules) and in their accessibility to antigen in the environment. THE STRUCTURE OF PERIPHERAL LYMPHOID TISSUE For many years it has been clear that spleen and lymph nodes are the tissues most directly concerned with immune processes. For technical reasons, most recent experimental work on cellular immunology has been concerned with the cells of accessible lymph nodes, either popliteal or auricular, and it will be convenient to base general discussion of the function of lymphoid tissue on this work. In all probability the lymphoid tissue of the spleen and the extensive accumulations of lymphoid tissues along the alimentary tract, from tonsils downward, play a basically similar role. Lymph node structure The essential features of a peripheral lymph node are shown in fig. 15. The afferent lymph carrying any antigenic material from its catchment area enters at the periphery and is distributed over the lateral sinus, from which it percolates through more or less definite channels into the cortex and eventually is collected into the lymph sinuses associated with the medullary cords and brought to the efferent lymph vessels at the hilus. Lying immediately beneath the lateral sinus is the cortical tissue with a number of areas of more closely packed small lymphocytes, the primary lymph follicles. Within these, secondary follicles or germinal centres develop under antigenic stimulation. Toward the hilum of the node the medullary cords, more or less closely packed, repre¬ sent essentially small blood vessels surrounded by a sheath of 85
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