ageing and immunity Flashcards
list diseases associated with ageing
name the 3 hallmarks of ageing
What are the four interdependent hallmarks of the senescence phenotype?
- Cell-cycle withdrawal: Cells stop dividing.
- Macromolecular damage: Accumulation of damage to biomolecules like proteins and DNA.
- Secretory phenotype (SASP): Senescent cells release inflammatory molecules.
- Deregulated metabolism: Altered energy and metabolic pathways.
What is SASP, and why is it significant in ageing?
SASP (Senescence-Associated Secretory Phenotype) involves the release of inflammatory molecules by senescent cells, contributing to tissue damage and ageing.
What happens during cell-cycle withdrawal in senescence?
Cells permanently stop dividing, marked by a halt in the cell cycle.
How does macromolecular damage contribute to senescence?
Damage to DNA, proteins, and lipids disrupts cellular function.
What does deregulated metabolism mean in senescent cells?
Abnormal energy production and inefficient metabolic processes.
What happens to phagocytosis in ageing?
decreases
what is immunosenescence
Immunosenescence, defined as the changes in the immune system associated with age
What changes occur in macrophages during immunosenescence?
Increased production of inflammatory cytokines.
How do neutrophil functions change with age?
Reduced NETs and oxidative burst.
What happens to NK (natural killer) cells in ageing?
Decreased IFN-γ production.
What is inflammaging?
Chronic, low-grade inflammation due to ageing.
What contributes to inflammaging?
Hormones, metabolites, PAMPs/DAMPs, and cellular debris.
What key pathway is activated in inflammaging?
NF-κB.
What are the consequences of inflammaging?
Increased inflammatory cytokines, impaired autophagy, proteostasis changes, mitochondrial dysfunction, microbiota dysbiosis, and cell senescence.
What happens to B cells during immunosenescence?
Decreased AID activity and BCR repertoire, reduced antibody levels, and diversity.
How are T cells affected by immunosenescence?
Reduced naïve T cell signalling and increased memory T cells (CD28-, PD-1+, Tim3+, Th2).
What happens to naïve and memory immune cells?
Naïve cells decrease; memory cells become exhausted.
What happens to T cells during immunosenescence?
- Naïve T cells: Decrease.
- Memory T cells: Increase.
- TCR diversity: Decreases.
- Effector T cells: Decline.
- Antigen recognition repertoire: Decreases.
What changes occur in NK cells during ageing?
How are dendritic cells affected by immunosenescence?
Reduced antigen presentation.
Decreased endocytosis.
Lower IFN production.
What happens to macrophages with ageing?
Decreased number and function.
Reduced antigen presentation.
Impaired phagocytosis.
How are B cells affected by immunosenescence?
Naïve B cells: Decrease.
Memory B cells: Decline in function.
Antibody production: Decreases in diversity and effectiveness.
what happens to Myeloid-Derived Suppressor Cells (MDSCs) during ageing?
Number and function: Both increase.
What are the overarching consequences of immunosenescence?
Reduced immune response effectiveness.
Increased susceptibility to infections and chronic diseases.
