B Cells Flashcards
What does the humoral response involve?
Involve B cells and antibodies which are soluble and transported in bodily fluids
Humour:old term for bodily fluid’s
Approximately how many different B cells do we have?
10 million which are antibodies on the their surface complementary to 10 million different antigen
Describe the process which B cells go through in the humoral response
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.
For how long can memory T cell live?
For decades but plasma lives for shorter time
What is active immunity?
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
State the concentration of antibodies in primary and secondary response.
The primary is lower than the secondary due to the memory T cells present in body it is a faster response
What are antibodies?and what they composed of?
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
How do the antibodies help to destroy pathogens?
Agglutination
They are flexible and bind to multiple antigens to clump together so it easier to locate and destroy pathogen by phagocytosis
How can lymphocytes distinguish between pathogens and self cells?
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.
State the different surface molecule enable if non-self cells to be recognised
-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
What is autoimmune system?(auto:suicide)
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
What is antigen variability?
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.
What is the hinge region?
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)
How is the antigen antibody complex formed?
antibody has a specific binding site that fits precisely onto a specific antigen to form an antigen-antibody complex
How do antibodies destroy pathogens?(agglutination)
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)
Reference to markers how do antibodies destroy pathogens?
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
Reference to toxins how to antibodies destroy pathogens?
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.
Reference to host cells how do antibodies destroy pathogens?
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
State the 6 function of an antibody.
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)
What is the evidence form antibodies structure has a quaternary structure?
Has more than one polypeptide chain
Scientists use this antibody to detect an antigen on the bacterium that causes symptoms,how do the antibody interact with antigen?
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
Describe how phagocytosis of a virus leads to presentation of its antigens.
Phagosome fuse with lysosomes
Hydrolytic enzyme destroy by lysosomes
Peptides/antigen from virus are on cell membrane
Describe how presentation of a virus antigen leads to secretion of an antibody against this virus antigen
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
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)
The antibody against virus will bind to collagen and results in collagen destroying
