Immune Memory/Trained Immunity

Question 1

What is Immunological Memory?

Answer 1

• Ability of immune system to remember antigens and mount a a resposne of greater magnitude and with faster kinetics.
• Link between present and past antigenic experience.

Question 2

What is the mechanisms of Immunological Memory?

Answer 2

• Sliding scale of memory, not hard and fast rule.
• Not necessarily confined to adaptive immunity.
• Innate memory in NK, monocytes, DC< ILCs, gamma-delta T-cells, NKT
• During adaptive response (slow and antigen specific) it generates long-term immunological memory and during innate response (fast and non-specific) is incapable of building immunological memory.

Question 3

What are the characteristics of memory B-cells?

Answer 3

1. Make antibodies: IgM mostly, IgG, makes LLPC and memory B
2. Make antibodies: IgG mostly, from LLPC, immediate and effective also help T-cells by Ag presentation

Memory cells in Secondary Lymph nodes or tissues

Question 4

Characteristics of memory T-cells

Answer 4

Naive T-cell gets activated to effectors –> memory after clearance –>more rapid/efficient response after rechallenge

Remember 1st antigen encounter and 2nd antigen encounter

Question 5

An activated naive T-cells differentiate into three major circulating subset, which ones?

Answer 5

• Stem cell memory T (Tscm) cells
• Central memory T (Tcm) cells
• Effectory memory T (Tem) cells

Question 6

Describe how a Resident Memory cells (Trm) are form?

Answer 6

• Effector memory T (Tem) cells differentiate into Effector (Teff) cells when Ag exposure.
• Naive, Tscm and Tcm cells circulate and migrate to lymphoid tissue.
• Tem and Teff cells have the capacity to traffic to peripheral tissues and become tissue resident memory cells (Trm)
• Trm in the peripherial compartments and terminally differentiated do not circulate or convert to other memory T-cell subsets.

Question 7

What is the heterogeneity (presence) of memory T-cells in the blood and tissues?

Answer 7

Question 8

What is the durability of the immune memory response?

Answer 8

Durability = quality of Ag

longevity of smallpox vax-specific B-cell memory: more than 60 years

Question 9

Review

What are some of the characteristics from the innate and adaptive immunity?

Answer 9

Innate:
* Rapid and effective
* Non-specific, indiscriminate
* Lacks immunological memory

Adaptive
* Needs 10 to 14 days
* Specific activation against a particular microorganism, enhacing the effect of the response
* Builds immunological memory

Question 10

Insects, plants and other living organisms live withour immune memory
True or False

Answer 10

FALSE

Most living organism do not have adaptive immune system