B Cells

Question 1

What does the humoral response involve?

Answer 1

Involve B cells and antibodies which are soluble and transported in bodily fluids
Humour:old term for bodily fluid’s

Question 2

Approximately how many different B cells do we have?

Answer 2

10 million which are antibodies on the their surface complementary to 10 million different antigen

Question 3

Describe the process which B cells go through in the humoral response

Answer 3

B cell is triggered when the antigen is complementary to antigen and takes antigen by Endocytosis and then presents it on cell surface membrane
-the B cells collides with helper T cells in order to go through clonal expansion and differentiation (clonal selection)
-they undergo mitosis to make larger number of cells these differentiate into plasma cells or memory B cells

-Plasma can be able to make antibodies
-B memory cells can be able to divide rapidly into plasma when re-infected with same pathogen to make large numbers of antibodies rapidly.

Question 4

For how long can memory T cell live?

Answer 4

For decades but plasma lives for shorter time

Question 5

What is active immunity?

Answer 5

memory T cells are able to divide by mitosis to produce plasma cells when encountered with the same pathogen again
So antibodies are made so that pathogen is destroyed before any symptoms occur

Question 6

State the concentration of antibodies in primary and secondary response.

Answer 6

The primary is lower than the secondary due to the memory T cells present in body it is a faster response

Question 7

What are antibodies?and what they composed of?

Answer 7

Quaternary protein structure
(4 polypeptide chain with 2 distinct different regions) like “Y”
Play a role in specific immune response

-Top of / is the variable region which is complementary to antigen
- The | and some of the / is the constant region so it won’t change
-heavy chain is longer this heavy the | part as there are more amino acids there
- and the \/ is light chain due to being shorter

Question 8

How do the antibodies help to destroy pathogens?

Answer 8

Agglutination
They are flexible and bind to multiple antigens to clump together so it easier to locate and destroy pathogen by phagocytosis

Question 9

How can lymphocytes distinguish between pathogens and self cells?

Answer 9

Each has a molecule on its surface to identify it,usually made up of protein and their 3D tertiary structure enables lots of unique and identifiable shapes to be made.

Question 10

State the different surface molecule enable if non-self cells to be recognised

Answer 10

-Pathogen-bacteria fungi viruses like HIV
-Cells from other organisms of same species (organ transplant)
-abnormal body cells like cancer cells
-toxins which pathogens releases into blood such a cholera

Question 11

What is autoimmune system?(auto:suicide)

Answer 11

Lymphocytes attacks the body’s own cells and tissues, treating them as foreign invaders. This can lead to various autoimmune diseases, such as rheumatoid arthritis, lupus, or type 1 diabetes

Question 12

What is antigen variability?

Answer 12

refers to the ability of pathogens, like bacteria or viruses, to change the proteins on their surface (antigens) in order to challenge the immune system to build an effective and targeted response, allowing the pathogen to persist and potentially cause recurrent infections.

Question 13

What is the hinge region?

Answer 13

It is the region in which allows flexibility so that the antibody molecule can grip to more than one antigen(can bind 2 allowed by hinge region or 1)

Question 14

How is the antigen antibody complex formed?

Answer 14

antibody has a specific binding site that fits precisely onto a specific antigen to form an antigen-antibody complex

Question 15

How do antibodies destroy pathogens?(agglutination)

Answer 15

They prepare them for destruction
As different lead to the destruction of antigens
They cause agglutination of pathogen cells forming clumps of cells that are easier for phagocytes to locate and engulf
(Possible as each antibody as 2 antigen binding site)

Question 16

Reference to markers how do antibodies destroy pathogens?

Answer 16

They do this by binding to specific markers, such as antigens, on the surface of the pathogens. This binding can directly neutralize the pathogen or can flag it for destruction by other immune cells. In essence, antibodies act as molecular markers that tag pathogens for elimination

Question 17

Reference to toxins how to antibodies destroy pathogens?

Answer 17

Antibodies neutralize pathogens by binding to toxins produced by the pathogens. This binding prevents the toxins from harming the body’s cells and marks the pathogen for removal by immune cells.

Question 18

Reference to host cells how do antibodies destroy pathogens?

Answer 18

Antibodies aid in the destruction of pathogens(protein on viruses)by binding to them, preventing the pathogens from entering host cells. This binding can also mark the pathogens for attack by immune cells

Question 19

State the 6 function of an antibody.

Answer 19

1-Active B lymphocytes- can be plasma cell or memory cells

2-Acts as opsonins- these are proteins that when bound to a substance or cells induce phagocytes to phagocytose the cell,so it stimulates production of phagocytes through complex processes

3-cause antigen clumping and inactivation of bacterial toxins

4-actives antibody dependent cellular activity

involves antibodies marking pathogens, and immune cells called cytotoxic cells recognizing these markers. The immune cells then attack and destroy the marked pathogens

5-triggers mast cells degranulation breaking down cell

6-activation of complement(next thing that will happen)

Question 20

What is the evidence form antibodies structure has a quaternary structure?

Answer 20

Has more than one polypeptide chain

Question 21

Scientists use this antibody to detect an antigen on the bacterium that causes symptoms,how do the antibody interact with antigen?

Answer 21

Antibody has variable region which has specific amino acids sequence (primary structure)

The shape of binding site is complementary to antigens

Forming an antigen antibody complex

Question 22

Describe how phagocytosis of a virus leads to presentation of its antigens.

Answer 22

Phagosome fuse with lysosomes
Hydrolytic enzyme destroy by lysosomes
Peptides/antigen from virus are on cell membrane

Question 23

Describe how presentation of a virus antigen leads to secretion of an antibody against this virus antigen

Answer 23

Helper T cells bind to antigen on the APC this allows the stimulates a specific B cell
B clones and divides by mitosis(clonal expansion)form plasma release antibodies

Question 24

Collagen is a protein made by cells in joints (knee)
And RA is an autoimmune disease,and a person immune system attacks their own cells and RA cause pain and swelling stiffness in joints.

Scientists have found a virus to this viral protein can result in developing of RA
Suggest how immune response to this viral protein can result in the development of RA(rheumatoid arthritis)

Answer 24

The antibody against virus will bind to collagen and results in collagen destroying