Differential expression ofcell adhesion molecules inthefunctional compartmentsof lymphnodesandtonsils

Aims-Toanalyse thetopographical distribution ofadhesion molecules involved inlymphocyte recirculation in human lymphnodesandtonsils. Thestudyfocusedon theexpression ofLECAM-1 (CD62L),VLA-a4 (CD49d),VLA-p1 (CD29),LFA-1 aL (CD11a),LFA-P2 (CD18),VCAM-1 (CD106),ICAM-1 (CD54), andH-CAM (CD44). Methods-Reactive lymph nodesand palatine tonsils werestudied usingimmunofluorescence methodswithfluoresceinisothiocyanate (FITC)labelled monoclonal antibodies directed against cell adhesion molecules. Toinvestigate the expression patterns ofthesemolecules in theTandB cell populations, double labellingexperiments wereperformed using TexasRedlabelled antibodies against CD2 orCD19,respectively. Theimagesfrom each fluorochrome were then simultaneously analysed usinga laser scanningconfocal microscope. Results-LECAM-l, VLA-a4andH-CAM werepredominantly expressed bymantle zoneB cells, VCAM-1 andICAM-1by germinal centrecells, mostofwhichexhibited a reticular staining pattern suggestiveof follicular dendriticcells, whereasLFA-1aL and LFA-P2were mainlyfoundinextrafollicular andgerminalcentreT cells. Allhighendothelial venules expressed VLA-P1andICAM-1, whereasVCAM-1 waspresent inonlya few,withvariable intensity. Conclusions-The datashowthatallof these adhesion molecules aredifferentially distributed withinthedistinct functional microenvironments ofbothorgans.The differences observed intheexpression patternsamongtheB andT cells belonging todifferent compartments probably dependonthemomentum ofcell traffic, the stageofmaturationlactivation, aswellas on theirfunctional roleintheimmune response. (JClin Pathol: MolPathol 1995;48:M93-M100)