based upon own investigations the significance of cell-inherent factors on age-dependence of cell-mediated immunity is underlined , consisting of an age-correlated alteration of a t-cell subpopulation the increasing morbidity or mortality of infectious diseases , i.e . tuberculosis , salmonellosis and viral hepatitis in the older age-group , additionally , may be explained by a reduced cell-mediated immunity known to play an important role in immune defense mechanisms particulary in these diseases .
C0009450
infectious diseases
C0012634
diseases