The heterogeneity of the age-related decline in immune response: impairment in delayed-type hypersensitivity and cytotoxic T-lymphocyte activity occur independently.
Aged mice are known to have a heterogeneous cytotoxic T-lymphocyte (CTL) response to an influenza challenge. We sought to determine whether delayed-type hypersensitivity (DTH) to sheep red blood cells (SRBC) was also heterogeneous in aging and, if so, whether this correlated with anti-influenza CTL activity. Aged mice developed mean footpad swelling of 0.24 +/- 0.09 mm following SRBC challenge and mean CTL activity of 35 +/- 18%. Even though these values were significantly lower than those from young mice (0.54 +/- 0.10 mm and 51 +/- 2%, respectively), no correlation was found between anti-influenza CTL activity and DTH to SRBC (r = 0.01). We believe the most likely reason for this independent decline in immune response is because different activation signals are required for DTH and CTL activity. Our data thus suggest an age-related functional mosaicism in the immune system.
Bender
B S
BS
Geriatric Research, Education and Clinical Center, Department of Veterans Affairs Medical Center, Gainesville, Florida 32608-1197.
Tallman
E
E
D000375:Aging / Q000502:physiology*; D000818:Animals; D000917:Antibody Formation; D004912:Erythrocytes / Q000276:immunology; D005260:Female; D006968:Hypersensitivity, Delayed / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D009976:Orthomyxoviridae Infections / Q000276:immunology; D012756:Sheep / Q000097:blood; D013154:Spleen / Q000166:cytology / Q000276:immunology; D013602:T-Lymphocytes, Cytotoxic / Q000502:physiology*