The memory B cell response to influenza vaccination is impaired in older persons

Influenza imparts an age-related increase in mortality and morbidity. The most effective countermeasure is vaccination; however, vaccines offer modest protection in older adults. To investigate how ageing impacts the memory B cell response we tracked haemagglutinin specific B cells by indexed flow sorting and single cell RNA sequencing in twenty healthy adults administered the trivalent influenza vaccine. We found age-related skewing in the memory B cell compartment six weeks after vaccination, with younger adults developing haemagglutinin specific memory B cells with an FCRL5+ "atypical" phenotype, showing evidence of somatic hypermutation and positive selection, which happened to a lesser extent in older persons. We confirmed the germinal center ancestry of these FCRL5+ "atypical" memory B cells using scRNASeq from fine needle aspirates of influenza responding human lymph nodes and paired blood samples. Together, this study shows that the aged human germinal center reaction and memory B cell response following vaccination is defective. SummaryImmune responses to vaccination wane with age. Using single cell RNA sequencing of influenza vaccine specific B cells, this study delineates changes in B cell memory generation, antibody mutation and their subsequent selection in older persons.