Induction of lymphocyte recruitment in the absence of a detectable immune response

Lymphocyte recruitment from blood into the lymph node is thought to be init iated by the presence of antigen. In this study, we have used lymphatic can nulation in sheep to demonstrate that the adjuvant ISCOMATRIX(TM) can induc e dramatic lymph node activation in the absence of antigen. Consistent patt erns of node shutdown (decreased output) and cell recruitment (increased ou tput) with minimal blast cell responses were observed indicating that an an tigen-specific immune response is not required. Production of IL-6, IL-8 an d IFN-gamma, and the transient presence of red blood cells and neutrophils in the efferent lymph were associated with changes in efferent lymph cell t rafficking. These early events may facilitate the screening of low frequenc y antigen-specific cells for binding to antigen and the subsequent amplific ation of the immune response. (C) 2000 Elsevier Science Ltd. ALI rights res erved.