The tonsils provide defense of the upper aerodigestive tract against pathogens. Although long known to undergo functional changes with age, the precise changes occurring within tonsillar B cell populations remain undefined. In the present study, we investigated age-related changes in palatine tonsillar B cell subsets and immunoglobulin (Ig) isotypes. Palatine tonsils were obtained from forty-two tonsillectomy patients without tonsillitis who were divided into three groups: young children (4–9 years), adolescents (10–19 years), and adults (20–60 years). Tonsillar B cells were then analyzed by flow cytometry. Using expression of CD38 and IgD to define B cell subsets, we found that the frequency of germinal center (GC) B cells in the tonsils was significantly higher, and the frequency of memory B cells lower, in young children as compared to adolescents and adults. Within the GC B cell subsets, adults had a higher frequency of IgA+ cells and a lower frequency of IgM+ cells as compared to individuals in the younger age groups. Moreover, young children had a higher frequency of IgG+ cells in the GC B cell subsets than did individuals in the older age groups. We also observed an abundance of IgM+ cells among memory B cells and plasmablasts in young children and IgA+ cells in adults. In summary, the proportion of GC B cells in palatine tonsillar B cells decreases with age, while the proportion of memory B cells increases with age. In addition, Ig isotypes in tonsils preferentially switch from IgM to IgA as individuals age.

Age-related differences in human palatine tonsillar B cell subsets and immunoglobulin isotypes

RACANELLI, Vito;
2016-01-01

Abstract

The tonsils provide defense of the upper aerodigestive tract against pathogens. Although long known to undergo functional changes with age, the precise changes occurring within tonsillar B cell populations remain undefined. In the present study, we investigated age-related changes in palatine tonsillar B cell subsets and immunoglobulin (Ig) isotypes. Palatine tonsils were obtained from forty-two tonsillectomy patients without tonsillitis who were divided into three groups: young children (4–9 years), adolescents (10–19 years), and adults (20–60 years). Tonsillar B cells were then analyzed by flow cytometry. Using expression of CD38 and IgD to define B cell subsets, we found that the frequency of germinal center (GC) B cells in the tonsils was significantly higher, and the frequency of memory B cells lower, in young children as compared to adolescents and adults. Within the GC B cell subsets, adults had a higher frequency of IgA+ cells and a lower frequency of IgM+ cells as compared to individuals in the younger age groups. Moreover, young children had a higher frequency of IgG+ cells in the GC B cell subsets than did individuals in the older age groups. We also observed an abundance of IgM+ cells among memory B cells and plasmablasts in young children and IgA+ cells in adults. In summary, the proportion of GC B cells in palatine tonsillar B cells decreases with age, while the proportion of memory B cells increases with age. In addition, Ig isotypes in tonsils preferentially switch from IgM to IgA as individuals age.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11586/170905
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