NewCellSurface Antigens inRatDefined byTumorsoftheNervousSystem (glial andneuronal celllines/ethylnitrosourea-induced tumors/embryonic antigens/brain antigens)

Tumorsofthecentral andperipheral ner- voussystemwereinducedinratswithethylnitrosourea. Many ofthesetumorsweretransplanted insyngeneic recipients, andseveral celllineswerederived fromthem. An antiserukn raisedagainstone suchcelllineinC3H micedefined twocellsurface antigens incytotoxicity tests. One,thecommon antigen, waspresent onratbrainand embryonic tissues andwaspresentinlargeamountson mosttumorsorcell lines fromthenervoussystem.Fibro- blastic celllineshad smalleramountsofthisantigen, whichalsocouldbedetected byimmunofluorescence. The other,restricted antigenwasnotdetected on normalor embryonic tissues. Itwaspresent onsixtumorsfromthe nervoussystem,ononeglial cellline, andona Schwann- cell lineRN22.Inaddition, itwaspresent on fouroutof eleven cloned celllinesisolated fromrattumorsatthe SalkInstitute. Two ofthepositive clonal lineshadbeen showntohaveproperties uniquetoneuronalcells. The restricted antigenwastherefore expressed onthecellsur- faceofsome,butnotall,glial, Schwann,andneuronal neoplastic cells. Thestudy ofneural* cells intissue culture provides anew approach toquestions ofthefunctions andinteractions ofthe different populations ofcells inthenervous system. However, physical methods forseparating thedifferent cell types have severe limitations, andidentification ofcells thathavebeen treated withenzymes orgrownintissue culture istime-con- suming anddifficult. Theuseofsurface antigens fordisting- uishing, separating, andstudying thefunction ofdifferent types oflymphocytes (1)hassuggested apossible immuno- logical approach totheproblems ofneural cell populations. Anumberofmurine allo-antigens (Thy-i, PC1,Sk,andH-2) areknowntobepresent inmousebrain; ifanyoneofthem wererestricted toasubset ofneural cells, itmight beauseful marker (2). Inaddition, newcell surface markers havebeen defined byusing tumors ofthenervous system. Recently an antigen onbrain andmurine neuroblastoma C1300 (3), anda glial-specific brain antigen carried byoligodendroglioma