Adaptive Immunity

Question 1

Which organisms or animals do have adaptive immunity?

Answer 1

Only vertebrate organisms

Question 2

How specific is the adaptive immune system?

Answer 2

Highly specific

Question 3

In humans, adaptive immune system is sub-divided into?

Answer 3

Humoral immunity

Cellular immunity

Question 4

Hallmarks of the adaptive immune system

Answer 4

Specificity

Memory

Question 5

Cells of humoral immunity

Answer 5

B-cells, (matures to plasma cells)

Question 6

Cells of cellular immunity

Answer 6

• CD4+ helper T cells
• CD8+ cytotoxic T cells

Question 7

What is plasma cell?

Answer 7

Fully differentiated B lymphocytes that produces single type of antibody

Question 8

Which immunity is referred to as ‘circulating immunity’?

Answer 8

Humoral immunity

Question 9

Basic steps of humoral immunity

Answer 9

Pathogens are visible in circulating fluids (blood, lymph etc.) >>>>> B cells matures & becomes plasma cells (class switching) >>> produce antibodies those are specific to those pathogens >>>>> antibodies encounter the pathogens >>>>> production of memory cells >>>>> when the same pathogen enters again in the body >>>>> more effective and rapid response

Question 10

Why is cellular immunity needed?

Answer 10

Many pathogens reside inside cells >>>>> thus evade humoral immunity; Example: viruses

So, cellulary immunity recognise those intracellular pathogens

Question 11

If a virus or pathogen reside inside cells (intra-cellular), how can those be recognised?

Answer 11

“Almost all” cells are able to express the samples of their intracellular contents >>> on their cell surface >>> using machinery called ‘HLA system’

Question 12

What is HLA?

Answer 12

Human Leukocyte Antigen

Question 13

Chromosome and Region of HLA system

Answer 13

Chromosome 6

Region: MHC (Major Histocompatibility Complex)

Question 14

Which cells do express class-I HLA?

Answer 14

Most cells

(so, it is thought to be a form of house-keeping)

Question 15

Which class of HLA is thought to be a form of house-keeping?

Answer 15

Class-I HLA

Question 16

Which cells do express class-II HLA?

Answer 16

Small number of APCs (Antigen Presenting Cells)

(These are the cells of innate immunity (that spend their days) >>> to pathogocytose extracellular material >>> express antigens)

Question 17

What does interact with HLA?

Answer 17

Cellular immune system (T cells)

Question 18

What is the purpose of interaction between HLA and T cells?

Answer 18

to determine whether the ‘peptides’ expressed are self or non-self

Question 19

Memory with the adaptive immune system (flow-chart)

Answer 19

• Initial exposure >> Immediate response + IgM production

>>>>> Later: Memory cells production + IgG production

• ​Repeat exposure > IgG mediated response (immediately)