B-cell senescence

B-cell senescence covers the age-related changes in your B cells (the antibody-making immune cells) that weaken your antibody immunity. A hallmark is the buildup of 'age-associated B cells' (ABCs). These are marked by certain proteins (T-bet, FcRL5, CD11c, and usually CD21-low/CD27-negative). They expand with age and in autoimmune disease, and they are poor at joining germinal-center reactions. Germinal centers are where antibodies get refined (through somatic hypermutation and affinity maturation). With age, these reactions shrink in size and quality. The result is lower-affinity, less class-switched antibodies. Together these changes weaken your vaccine responses and raise the odds of self-reactive, low-quality antibodies in older adults.

Last reviewed: June 22, 2026

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