BcellandTcelllymphocytesinteractwithavarietyofcellsaspartoftheirimmunefunction,circulatingandhominginonspecificstimuliintissueslikeinflammatorysignals.TheinteractionoflymphocyteswithothercelltypeslikevascularendothelialcellsrequirestransmembraneadhesionmoleculeslikeVLA-4,LFA-1,CD44,CD31andL-selectin.Eachoftheselymphocyteadhesionmoleculesinteractswithspecificligandsexpressedoncellslikeendothelialcellstomoderateadhesionbetweencells.CD44isanadhesionmoleculewithmanyroles,includinginteractionofleukocyteswithendothelialcellsinresponsetoinflammation,withthemostoftenstudiedligandbeinghyaluronan,acomponentoftheextracellularmatrix.LFA-1,Leukocytefunction-associatedmolecule1,isanintegrincomposedoftwosubunits,CD11aandCD18.LFA-1moderatesadhesionoflymphocyteswithothercellsandalsotransducessignalsintocellsthroughinteractionwithICAM-1expressedonendothelialcells.ExpressionofICAM-1(CD54)isincreasedbyinflammatorysignals,increasingadhesionandpermeationoflymphocytesintoinflamedtissues.VLA-4isanotherintegrinexpressedonlymphocytesthatplaysaroleinadhesionthroughinteractionwithitsadhesionpartneronendothelialcells,VCAM-1.L-selectinappearstomediateadhesionthroughbindingofalectin-likedomaintocarbohydrates.PECAM-1(CD31)isexpressedonendothelialcellsandisinvolvedinangiogenesisaswellasadhesionbetweencells.VAP-1isanadditionalproteinexpressedbylymphocytesandinvolvedinadhesiontovascularendothelialcells. Contributor:GlennCroston,PhD. REFERENCES:
