ABSTRACT
Lymph is a product of diffusion and filtration of plasma components. Thus, the actual composition of lymph is dictated by capillary filtration rate, permeability of the capillary wall, metabolic state of parenchymal cells, and tissue fluid and lymph transport away via lymphatics. The interstitial fluid to be compared to the lymph is the free interstitial fluid remaining in thermodynamic equilibrium with the interstitial gel. In the protein-producing organs, the lymph protein concentration is lower than in serum. Immune proteins found in the peripheral lymph may originate from three sources: plasma, tissue from which lymph is drained, and free-floating lymph cells. Different lymphokines have been found in lymph draining from tissue that has received local application of antigen. Efferent lymph from the popliteal node of sheep challenged with antigen was found to suppress the in vitro transformation of sheep peripheral blood lymphocytes to a variety of antigens.
