Age-related changes in LFA-1 expression, cell adhesion, and PHA-induced proliferation by lymphocytes from senescence-accelerated mouse (SAM)-P/8 and SAM-R/1 substrains.
Accelerated senescence-prone mice of the SAM-P/8jf series were compared with senescence-resistant SAM-R/1 controls in terms of age-related changes in phytohemagglutinin (PHA) proliferative responses and lymphocyte function-associated antigen-1 (LFA-1) utilization by non-adherent splenocytes. Advancing age was associated with a reduction in cell proliferative responses to PHA in both substrains, although the rate of decline was significantly more rapid in the senescence-prone animals. Conversely, in both substrains there was a progressive age-related increase in the proportion of splenocytes expressing high levels of LFA-1, and a parallel increase in the degree of LFA-1-dependent cell aggregation induced by phorbol ester. Age-matched SAM-P/8jf and SAM-R/1 mice did not differ in terms of LFA-1 expression or LFA-1-dependent cell aggregation. Two-color cytofluorometric analysis demonstrated the enhanced expression of LFA-1 expression by cells bearing the Pgp-1hi phenotype characteristic of memory lymphocytes. These results suggest that age-associated changes in lymphocyte adhesion are attributable to alterations in the relative numbers of memory cells expressing high levels of LFA-1, but are unlikely to contribute to the reduced proliferative response to mitogen in aged mice.
Powers
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DC
Geriatric Research Education and Clinical Center, St. Louis VAMC, Missouri 63125.
Morley
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JE
Flood
J F
JF
D000375:Aging / Q000276:immunology*; D000818:Animals; D002448:Cell Adhesion / Q000276:immunology*; D002449:Cell Aggregation / Q000276:immunology; D002455:Cell Division / Q000276:immunology; D007156:Immunologic Memory / Q000276:immunology; D016169:Lymphocyte Function-Associated Antigen-1 / Q000276:immunology*; D008214:Lymphocytes / Q000276:immunology*; D051379:Mice; D008815:Mice, Inbred Strains; D008954:Models, Biological; D010835:Phytohemagglutinins; D013154:Spleen / Q000166:cytology / Q000276:immunology
D016169:Lymphocyte Function-Associated Antigen-1; D010835:Phytohemagglutinins