studies on the effects of natural infection with parainfluenza type 1 virus ( sendai ) on the immune system of 8 strains and hybrids of aging mice revealed that ( a ) 55 of 63 indices tested were abnormal as late as 8 months after the disappearance of clinical systoms , ( b ) thymus weight and cell indices and lymph node t cell activity still exhibited a statistically significant negative correlation with age following infection , and ( c ) immunologically immature young and immunodeficient old mice suffered more severe sequelae following viral infection than did adult or middle-aged mice as determined by accelerated decline of thymus indices , mortality , igm coombs ' titer , and in the case of old mice , anemia .
C0020962
immune system
C0040113
thymus