Tlymphocytesexecuteandcontrolimmunologicalreactionswitharepertoireofcytokines,cytotoxicsubstances,andothermediators.ThequantitativeandqualitativeanalysisofCD4
+Tcellsspecificallyrecognizingandreactingtowardsadefinedantigenprovideimportantinformationtounderstandtheirfunctioninvariousimmunologicalsituations.Antigen-specificCD4
+Tcellscanbeidentifiedandcharacterizedbyanalyzingtheireffectorfunction,e.g.,productionofcytokinesandexpressionofCD154.