Sumbmitted to Blood November 2, 2012
Source
Department of Medicine, University of Toledo, Toledo, OH 43614, USA.
Department of Medicine, University of Toledo, Toledo, OH 43614, USA.
Abstract
The phenotype of B cells that respond to vaccination with the purified pneumococcal polysaccharide (PPS) has been a topic of debate. We have recently identified the phenotype of these cells as CD27+IgM+ B cells, in healthy young volunteers. However the PPS responding B cell population has not yet been identified in high risk populations, such as the elderly. Previous studies have shown that the elderly have a lower percentage of IgM memory B cells compared to healthy young adults. In this study we directly characterized the phenotype of PPS-specific B cells pre- and post-vaccination with the PPS vaccine (PPV) in elderly adults using fluorescently labeled PPS14 and PPS23F. In contrast to our observations in healthy young volunteers, the PPS-responding B cell population consisted primarily of switched memory (CD27+IgM-) B cells. In concurrence with these findings, post-vaccination IgM concentrations were not significantly increased in this population and the opsonophagocytic response was decreased compared to young adults. These findings identify a significant shift in the phenotype of responding B cell population in response to PPV with age.
The phenotype of B cells that respond to vaccination with the purified pneumococcal polysaccharide (PPS) has been a topic of debate. We have recently identified the phenotype of these cells as CD27+IgM+ B cells, in healthy young volunteers. However the PPS responding B cell population has not yet been identified in high risk populations, such as the elderly. Previous studies have shown that the elderly have a lower percentage of IgM memory B cells compared to healthy young adults. In this study we directly characterized the phenotype of PPS-specific B cells pre- and post-vaccination with the PPS vaccine (PPV) in elderly adults using fluorescently labeled PPS14 and PPS23F. In contrast to our observations in healthy young volunteers, the PPS-responding B cell population consisted primarily of switched memory (CD27+IgM-) B cells. In concurrence with these findings, post-vaccination IgM concentrations were not significantly increased in this population and the opsonophagocytic response was decreased compared to young adults. These findings identify a significant shift in the phenotype of responding B cell population in response to PPV with age.
Dr. Rebecca Thompson 