ABSTRACT
ThespecificitiesreportedtohavebeenassociatedwithCASarelistedinTable9.(Further discussionofthesespecificitiescanbefoundinrefs.17and100andinChapter3ofthis book.)
1.ImmunochemistryofPathogenicColdAutoagglutinins Withrareexceptions,pathogeniccoldautoagglutininsareIgM.Theyexhibitareversible, thermal-dependentequilibriumreactionwithRBCs,withassociationbeingfavoredatlower temperatures.Thethermalamplitudedependsontheconcentrationandequilibriumconstantof theantibody.ThecoldagglutininsassociatedwiththechronicidiopathicCASfoundinolder individualsarealmostalwaysmonoclonallgMproteins.Antibodiesofthemostcommon specificity(anti-1)almostalwayshaveonlyKlightchains;rareexamplesofanti-ioftenhave onlyX.lightchains(101-106).Thedemonstrationoftheexclusive,orvirtuallyexclusive, occurrenceofK-chainsinanti-Icoldagglutininswasthefirstexampleofarelationshipbetween antibodyspecificityandlightchaintype.Aminoacidsequencestudies,andstudiesoftheN terminalaminoacid,oflightchainsisolatedfromcoldagglutininlightchains,identifiedglutamic acidastheNterminalaminoacid,indicatingthattheybelongtothesubgroupVKII(107-108). Arestrictionwithintheheavy~J.-chainshasalsobeendemonstratedbypeptidemappingheavy chainsof14isolatedcoldagglutinins(109).Thirteenofthe14belongedtoone1-Lsubgroup, asshownbythelackofaparticularpeptidein40%ofmonoclonalM-globulinswithoutknown antibodyactivity(109).
