Adhesion molecules on peripheral blood lymphocyte subpopulations in the elderly
M De Martinis1, M Modesti, M F Loreto
1Department of Internal Medicine and Public Health, University of L'Aquila, Italy.
Insights
Aging alters immune cell adhesion molecules. Elderly individuals show reduced CD62L expression on lymphocytes but increased CD50 and CD62L intensity, indicating complex immune system changes with age.
Area of Science:
- Immunology
- Cell Biology
- Gerontology
Background:
- Adhesion molecules (e.g., CD49d, CD50, CD62L) are crucial for immune cell interactions.
- Immunological alterations are common in aged individuals.
- Understanding age-related changes in immune cell adhesion is vital for immune health.
Purpose of the Study:
- To investigate the expression and intensity of CD49d, CD50, and CD62L on peripheral blood lymphocyte subpopulations in healthy elderly subjects compared to young controls.
- To determine how aging affects the distribution and MFI of these key adhesion molecules on T cells, B cells, and NK cells.
Main Methods:
- Triple-color whole blood immunostaining.
- Multiparametric flow cytometry.
- Analysis of lymphocyte subpopulations (T, B, NK cells) in 23 elderly and 13 young healthy subjects.
Main Results:
- Elderly subjects exhibited decreased percentages and absolute numbers of lymphocytes expressing CD62L, including T, B, and NK cell subsets.
- While total lymphocyte counts expressing CD49d and CD50 were similar, their Mean Fluorescence Intensity (MFI) was higher for CD50 and CD62L in the elderly.
- T lymphocytes in the elderly showed increased MFI for CD49d, CD50, and CD62L compared to young controls, while B and NK cells showed no significant differences in antigen density.
Conclusions:
- Aging is associated with a significant reduction in CD62L-expressing lymphocytes, impacting T, B, and NK cell populations.
- The elderly display altered expression intensity of adhesion molecules, with increased CD50 and CD62L MFI on total lymphocytes and elevated CD49d, CD50, and CD62L MFI on T cells.
- These findings highlight age-dependent modulation of adhesion molecule expression, suggesting potential impacts on immune cell trafficking and function in older adults.
Abstract:
Adhesion molecules, such as CD49d, CD50 and CD62L, have important roles in many adhesive interactions involving cells of the immune system. Since it has been shown that many immunological alterations are present in aged subjects, we studied, by means of triple colour whole blood immunostaining and multiparametric flow cytometry, the expression and intensity level (MFI) of these molecules on peripheral blood lymphocyte subpopulations from 23 healthy elderly subjects and 13 young controls. In the elderly a decrease in total peripheral blood lymphocytes bearing CD62L antigen was observed (39 +/- 13% vs 63 +/- 6% and 745 +/- 312/mm3 vs 1,393 +/- 407/mm3; p<0.001), whereas the numbers of lymphocytes expressing CD49d and CD50 antigens were comparable in aged and young subjects. In addition, CD50 and CD62L MFI values on total peripheral blood lymphocytes were higher in elderly than in young subjects (5.23 +/- 1.03 vs 4.18 +/- 0.44, p = 0.001 and 2.60 +/- 0.35 vs 2.21 +/- 0.40, p = 0.005 respectively) while the intensity expression of CD49d was unchanged. The percentages and absolute numbers of T and B lymphocytes expressing CD62L were decreased in elderly compared to young subjects (CD62L+CD3+: 43 +/- 15% vs 66 +/- 9% and 581 +/- 257/mm3 vs 1,028 +/- 418/mm3, p<0.001; CD62L+CD19+: 78 +/- 12% vs 90 +/- 4%, p < 0.005 and 103 +/- 64/mm3 vs 207 +/- 98, p < 0.001). A decrease in the proportion of CD62L bearing NK cells was also observed in the elderly (25 +/- 14% vs 46 +/- 24%, p<0.005), although their absolute number was unchanged. No significant differences were detected in the proportion of T, B and NK lymphocytes expressing CD49d and CD50 antigens and only the absolute numbers of B cells expressing these adhesion molecules were lower in elderly (CD49d+CD19+: 121 +/- 71/mm3 and CD50+CD19+: 107 +/- 73/mm3) compared to young donors (CD49d+CD19+: 248 +/- 112/mm3 and CD50+CD19+: 235 +/- 120/mm3, p < 0.001). Moreover, the intensity of adhesion molecule expression was differentially modulated in the elderly depending on the specific lymphocyte cell population considered. The densities of CD49d, CD50 and CD62L antigens on B and NK lymphocytes from the two age groups were not different; on the contrary, T lymphocytes from elderly donors exhibited increased CD49d (1.69 +/- 0.09 vs 1.62 +/- 0.07, p < 0.05), CD50 (4.98 +/- 1.16 vs 3.77 +/- 0.46, p < 0.001) and CD62L (2.26 +/- 0.38 vs 1.99 +/- 0.37, p < 0.05) MFI values compared to young donors.
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