aging of the immune system

Question 1

what is our adaptive immunity?

Answer 1

it takes time to generate an adaptive response

-there is memory in this branch of immunity

-e.g. Polio or chicken Pox, years later your body will still recognize it

Question 2

adaptive immunity

self-non-self, lag phase, diversity, memory

Answer 2

self/ non-self discrimination: is the present, reaction against foreign

lag phase: present, response takes at least a few days

specificity: limited, the same response is mounted to a wide variety of agents

diversity: extensive, and resulting in a wide

memory: present, subsequent exposures to the same agent induce amplified responses

Question 3

what is our innate immunity?

Answer 3

natural, encoded in our germ line, present at birth

there is no memory for the innate branch, your body’s response would be the same when you are age 8 or age 12 years old

Question 4

innate immunity

self-non-self, lag phase, diversity, memory

Answer 4

self- non-self discrimination: the present, reaction is against foreign

lag phase: absent, response is immediate

specificity: limited, the same response is mounted to a wide variety of agents

diversity: limited, hence limited specificity

memory: absent, subsequent exposures to the agent generate the same response

Question 5

what is an interferon?

Answer 5

response primarily to viruses

Question 6

what do B cells respond to?

Answer 6

they respond to extracellular things like fungi for example

Question 7

evidence of immune aging

elderly humans

Answer 7

-increased susceptibility to pathogens

-decreased response to vaccination

Question 8

what is the thymus?

Answer 8

the thymus is an organ responsible for maturation of immune cells that help to protect the body from against foreign antigens

Question 9

thymic involution

Answer 9

decreased thymic output

adiposity in thymus

decreased thymic epithelial cells

iL-7 production

Question 10

Overall changes in older age

Answer 10

decreased telomerase activity

increased tumor incidence

increased infection susceptibility

increased autoimmune/inflammatory reactions

decreased response to vaccination

Question 11

inflamm-aging

Answer 11

increased inflammatory mediators

increased IL-6, C reactive protein

increased tissue dysfunction

Question 12

B lymphocytes

Answer 12

decreased naive B cell pool

increased memory B cell

decreased IgM, IgD serum levels

increased IgG, IgA serum levels

Question 13

T lymphocytes

Answer 13

decreased naive T cell pool

increased memory T cell

decreased TCR diversity

increased CD8 and decreased CD4

Question 14

what is the prevalence of infectious disease?

Answer 14

• infectious disease risk elevated in elderly

-severe impact on quality of life

-in the USA: pneumonia, influenza, septicemia- are among the top 10 leading causes of death

Question 15

why are the elderly more susceptible to covid-19?

Answer 15

after covid-19 disease was gone, people had prolonged inflammation release which causes damage in other places, lung damage and this contributed to why people died from disease even after it was gone

in an aged system, there is immunosenescence, inflammaging, viral antagonism, ARDS, cytokine storm, coagulopathy

Question 16

what is a cytokine storm

Answer 16

is an uncontrolled inflammatory release

Question 17

covid and the immune system

Answer 17

-recruitment of immune cells to infected sites

-widespread inflammation in lung, kidney, heart, liver, brain

-even with decreases in viral load

-can develop a cytokine release syndrome

Question 18

how is covid-19 controlled?

Answer 18

to suppress and eliminate the virus:
-recognition
-alert-activation of the immune system
-destroy the virus
-clear the virus

the recognition, alert/activation of immune system, destroying the virus, and clearing the virus are all changed in older adults

clearing of the virus also includes reducing inflammation safely

Question 19

vaccine efficiency

Answer 19

all the changes contribute to a lower vaccine response for older people

Question 20

exhausted T cells

Answer 20

overstimulated T cells, activated for prolonged time, tire out (become exhausted)

Question 21

Naive T cell

Answer 21

diverse when young, but this lessens with age

Question 22

antigen presentation

Answer 22

crosstalk between innate and adaptive immunity, reduced immune response between T and B cells

Question 23

proinflammatory monocytes

Answer 23

macrophages are still in the blood in the aged immune response

Question 24

decreased response to vaccination?

Answer 24

flu vaccine
-65-80% prevention for young adults
-30-50% in aged people( quite a substantial reduction)
-decreased B-cell production

e.g. influenza kills many older people

new vaccines
-decreased efficacy in older adults
-smaller T cell population