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Effect of age and CMV on NK cell subpopulations
Carmen Campos1, Alejandra Pera1, Beatriz Sanchez-Correa2
1IMIBIC, Reina Sofia University Hospital, University of Cordoba, Cordoba, Spain.
Abstract:
NK cells represent an important component of the innate immune response against infection and tumors. Age-associated changes in NK cell phenotype have been previously reported that can be responsible of functional NK cell deficiency. The aim of this work was to analyze the effect CMV seropositivity and aging on the distribution of NK cell subsets with a focus on the expression of cytotoxicity-related molecules and on the expression of CD94/NKG2 heterodimers and CD57 on these NK cell subsets. Our results show that CMV seropositivity in young individuals does not significantly affect peripheral blood NK cell percentage and NK cell subsets defined by the use of CD56 and CD16 markers. In contrast a significant increase in the percentage of NK cells is observed in elderly donors, all of them are CMV seropositive, when compared with young CMV seropositive subjects. A decrease in the percentage of CD56bright NK cells, either fully immature CD16 negative or CD16+ and an increase in the CD56-CD16+ subset are also found in the elderly. CMV seropositivity either in healthy young or elderly individuals is associated to the expression of CD94/NKG2C dimers and high expression of CD57on the CD56dimCD16+ NK cell subset. CD56-CD16+ NK cells, which are expanded in the elderly, show a decreased expression of granzymes A and B and an increased expression of CD94/NKG2C and CD57 in CMV seropositive young donors when compared with CMV seronegative young individuals. These results indicate that CMV and age have a different effect on NK cell phenotype and emphasize the relevance of including the determination of CMV serostatus in those studies addressed to analyze the immune response in the elderly.
Insights
Cytomegalovirus (CMV) seropositivity and aging significantly alter natural killer (NK) cell subsets. Elderly individuals, often CMV positive, show increased CD56-CD16+ NK cells with altered cytotoxicity markers.
Area of Science:
- Immunology
- Innate Immunity
- Cellular Immunology
Background:
- Natural killer (NK) cells are crucial for innate immunity against infections and tumors.
- Age-associated changes can lead to functional NK cell deficiency.
- Cytomegalovirus (CMV) serostatus is a known factor influencing immune cell phenotypes.
Purpose of the Study:
- To investigate the impact of CMV seropositivity and aging on NK cell subset distribution.
- To analyze the expression of cytotoxicity markers, CD94/NKG2 heterodimers, and CD57 on NK cell subsets.
- To differentiate the effects of CMV and aging on NK cell phenotype.
Main Methods:
- Flow cytometry analysis of peripheral blood NK cell subsets (CD56 and CD16 markers).
- Assessment of cytotoxicity-related molecules (granzymes A and B).
- Evaluation of CD94/NKG2C heterodimers and CD57 expression on specific NK cell subsets.
Main Results:
- CMV seropositivity in young individuals did not significantly alter NK cell percentages or subsets.
- Elderly donors (all CMV seropositive) exhibited increased total NK cell percentages compared to young CMV+ subjects.
- Elderly individuals showed a decrease in CD56bright NK cells and an increase in CD56-CD16+ NK cells.
- CMV seropositivity correlated with CD94/NKG2C and CD57 expression on CD56dimCD16+ NK cells in both young and elderly.
- Expanded CD56-CD16+ NK cells in the elderly displayed reduced granzymes A/B and increased CD94/NKG2C and CD57 in CMV+ individuals.
Conclusions:
- CMV infection and aging have distinct effects on NK cell phenotype and distribution.
- CMV seropositivity is associated with specific phenotypic changes in NK cell subsets, particularly CD56-CD16+ cells.
- Determining CMV serostatus is important for studies investigating immune responses in the elderly.
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