PROFILING OF NORMAL HUMAN LEG LYMPH PROTEINS USING THE 2-D ELECTROPHORESIS AND SELDI-TOF MASS SPECTROPHOTOMETRY APPROACH

The parenchymatous cells are supplied bynutrients transported in fluid from bloodacross the capillary wall. This fluid, calledtissue fluid (TF), contains proteins originatingfrom plasma as well as those synthesized andsecreted by tissue cells. The protein compositionof TF remains largely unknown. The TFwhich has entered lymphatics is called lymph(L). Harvesting L and measuring its proteinsconcentrations and identifying them providean insight into biochemical processes in theTF. Here we describe our initial evaluation ofthe normal human prenodal L protein profileof m. w. 2.5 to 12.5kDa using the Protein ChipSELDI MS system and compare it with that ofplasma (P) protein. This is the first study inthe literature providing evidence for thepresence of the so far non-identified proteinsin L as well as proteins identified in L butabsent from P and conversely present in P butnot in L. Evident differences between paired Land P samples have been found, along withsimilarities. Thirteen proteins were detected inP and seven in L in the region of 2.5 to 12.5kDa. Five identical proteins, although ofdifferent relative intensity, were found in Land P. The proteins specific for L but not Phad 7070 and 8619 ion values. P proteinsabsent from L were of 3890, 3969, 4078, 6863,7676, 7778, 7847 and 7937 ion values.In addition to detecting some so far unknownproteins in L, these preliminary findingsthrow a new light on our understanding ofthe mechanism of transcapillary transportof low m. w. proteins. They challenge thecommonly accepted notion of unlimited freediffusion of peptides across the capillarymembrane.