Biochemical changes in the efferent lymph plasma after oxazolone stimulation

The lymph node is a specialized microenvironment for the regulation of immu ne responses. The reticular network of the lymph node provides a structure that facilitates not only intercellular interactions, but the intranodal fl ow of lymph fluid. To assess biochemical changes in the nodal lymph plasma after antigen stimulation, prescapular lymph nodes in sheep were stimulated with the epicutaneous antigen oxazolone. The efferent lymph from both anti gen-stimulated and contralateral control prescapular lymph nodes was contin uously monitored for more than 120 h. The oxazolone-stimulated lymph plasma was associated with a selective increase in cholesterol content during the 'recruitment' phase of lymph node enlargement. The peak in cholesterol was followed closely by a significant increase in lymph plasma LDH concentrati on. In contrast, there was no significant difference between oxazolone-stim ulated and control lymph plasma in the concentration of triglycerides, albu min, alkaline phosphatase, and alanine transferase. These selective biochem ical changes in the efferent lymph appeared to reflect the dynamics of lymp hocyte activation within the lymph node as well as provide a practical meas ure of the lymph node response to antigen stimulation. (C) 2001 Elsevier Sc ience Ltd. All rights reserved.