18343lymphoid tissuePT0000-00-00 00:00:00BT19977tissuesPTBT18341lymphatic systemPTNT18345lymph nodesPTNT18342spleenPTNT18560thymus glandPTNT18648tonsilsPTRT18287lymphocytesPTRT18559lymphatic vesselsPTRT18344antibody formationPT