Selective Expressionofa VH1V Subfamily ofImmunoglobulinGenes inHuman CD5 + B Lymphocytesfrom Cord Blood

Summary Human B lymphocytesexpressingtheCD5 surfaceantigen(CD5+ B cells) constitute asubset capableofproducingpolyspecific antibodies recognizingavarietyofselfantigens.The repertoire ofantibodies producedby CD5+ andCD5 -B cellsisdifferent .However,itisnotyetestablished whether thisdistribution isreflected indifferent immunoglobulinvariableregiongene(IgV) use.RearrangementofheavychainIgV (IgV�)genesrepresents oneofthefirst identifiable stages inthematurationofB cells, and occursinadevelopmentallyorderedfashion .The repertoire ofIgVgene expressionishighlyrestricted duringfetallifebut diversifies progressively after birth.A highfrequencyofVgeneusefromtherelatively smallVIV genefamilyhaspreviously beendemonstratedinhuman fetalliverB cells .Inthepresentstudy,102B celllinesestablished by Epstein-BarrVirus-transformation ofseparatedCD5+ and CD5 - cordbloodB cells, were examinedforthefrequencyofIgVexpression usingmonoclonalantibodies tocross-reactive idiotypes (CRI).The resultsdemonstratearelatively highfrequencyofVIV geneuse(30%) inB cells fromcordblood.Furthermore,two mutuallyexclusive CRI associated withdistinct subgroups oftheVIV familyaresegregatedintheirassociation with eithersubsetofB cells .One CRI isexclusively expressedinlinesestablished from CD5 +B cellswhiletheotherisassociated with linesestablished from CD5 - B cells .