<n0:ComplexDefinition xmlns:n0="http://ncicb.nci.nih.gov/xml/owl/EVS/ComplexProperties.xsd#"><n0:def-definition>An immature T-lymphocyte, that has enlarged following stimulation by an antigen, has the capacity to recognize the stimulating antigen and is undergoing proliferation and differentiation either to eliminate the antigen or to a memory state in order to recognize the future appearance of the antigen.</n0:def-definition><n0:def-source>NCI</n0:def-source></n0:ComplexDefinition>