Jshek
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I understand what phagocytosis b cell and t cell do but I dont understand the difference

So phagocytosis is non specific and the same for all pathogen but t cell is specific to each pathogen

Why do we need t cells if white blood cell can just engulf it

In the picture below why does phagocytosis link with t cell . If phagocytosis happens it will engulf the antigen by lysozyme then why need t cell . Are they linked....

Confused
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Jshek
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Jshek
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Ok so I figured out phagocytosis happens first, presents the antigen on their surface,which t cell bind to,which activate B cell, stimulating production of antibodies.

But why make antibodies when the antigen are engulfed already by phagocytosis
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Jpw1097
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There is a degree of redundancy in the immune system. This means that different strands of the immune system will both be targeting the same pathogen. This is good because it allows a much quicker and robust response.

Phagocytes (e.g. neutrophils, macrophages) are part of the innate/non-specific immune system - they respond the same way each time. Some phagocytes such as macrophages and dendritic cells engulf pathogens, digest them and present their antigens on their surface. They present these antigens to B and T cells which activated them and activated the specific immune system.
B cells produce antibodies which bind to pathogens and has several effects, such as neutralising the pathogen. When antibodies bind to the pathogen, it also makes it easier for phagocytes to phagocytose the pathogen.
T cells are subdivided into helper T cells (of which there are many subtypes) and cytotoxic/killer T cells, which destroy infected cells.

Remember that in the specific immune system, memory B and T cells are produced. When reinfected with the same pathogen, these memory B and T cells become activated and this means the secondary immune response is much quicker and much stronger.
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Jshek
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(Original post by Jpw1097)
There is a degree of redundancy in the immune system. This means that different strands of the immune system will both be targeting the same pathogen. This is good because it allows a much quicker and robust response.

Phagocytes (e.g. neutrophils, macrophages) are part of the innate/non-specific immune system - they respond the same way each time. Some phagocytes such as macrophages and dendritic cells engulf pathogens, digest them and present their antigens on their surface. They present these antigens to B and T cells which activated them and activated the specific immune system.
B cells produce antibodies which bind to pathogens and has several effects, such as neutralising the pathogen. When antibodies bind to the pathogen, it also makes it easier for phagocytes to phagocytose the pathogen.
T cells are subdivided into helper T cells (of which there are many subtypes) and cytotoxic/killer T cells, which destroy infected cells.

Remember that in the specific immune system, memory B and T cells are produced. When reinfected with the same pathogen, these memory B and T cells become activated and this means the secondary immune response is much quicker and much stronger.
I'm so confused about humoral and cell mediated...
So t cells work on body cells and they can stimulate b cells to divide and secrete antibodies but how can it form antigen antibody complex because its humoral rather than cell mediated.
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Jshek
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(Original post by Jshek)
I'm so confused about humoral and cell mediated...
So t cells work on body cells and they can stimulate b cells to divide and secrete antibodies but how can it form antigen antibody complex because its humoral rather than cell mediated.
Wait so, cell mediated means t cells produce cytotoxic cells to destroy the infected cells only in body cell.....
And humoral means if antigen is in blood b cells produce antibodies that form antigen antibody complex
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(Original post by Jshek)
Wait so, cell mediated means t cells produce cytotoxic cells to destroy the infected cells only in body cell.....
And humoral means if antigen is in blood b cells produce antibodies that form antigen antibody complex
Humoral = antibodies.
Cell-mediated = does not involve antibodies. Both helper T cells and cytotoxic/killer T cells are involved in cell-mediate immunity.

Helper T cells have a wide range of functions and there are different subtypes of helper T cells, though that is beyond A-level. Some helper T cells release cytokines which activate and recruit neutrophils and other phagocytes, others help to activate B cells and therefore activate the humoral immune system, others may activate cytotoxic T cells. The immune system is very complex and it can be quite difficult to understand.
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Jshek
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(Original post by Jpw1097)
Humoral = antibodies.
Cell-mediated = does not involve antibodies. Both helper T cells and cytotoxic/killer T cells are involved in cell-mediate immunity.

Helper T cells have a wide range of functions and there are different subtypes of helper T cells, though that is beyond A-level. Some helper T cells release cytokines which activate and recruit neutrophils and other phagocytes, others help to activate B cells and therefore activate the humoral immune system, others may activate cytotoxic T cells. The immune system is very complex and it can be quite difficult to understand.
so is this the whole story

Pathogen enters the body.

phagocytosis happens which present the antigen on the phagocyte

t cells come along with complementary shape that binds to the antigen. which allows it to clone into many t cells,
the clone t cells help to

1.) memory cell
2.) stimulate phagocytes to pathgoen
3.) stimulate b cells tO divide and secrete antibodies
4.) cytotoxic cells which kill the infected cells

SO IF THE ANTIGEN ENTERS THE BLOOD STREAM, IT IS HUMORAL RATHER THAN CELL MEDIATED BECAUSE IT DOESNT INVOLVE BODY CELL AND IS INVOLVING ANTIBODIES PRESENT IN BODILY FLUID

ANTIGEN TAKEN UP BY B CELL

HELPER T CELL ATTCH TO ANTIGEN

ALLOWING B CELL TO DIVIDE BY MITOSIS TO GIVE PLASMA CELL..... antigen antibody complex


is it correct? im not sure if this bit is right "SO IF THE ANTIGEN ENTERS THE BLOOD STREAM, IT IS HUMORAL RATHER THAN CELL MEDIATED BECAUSE IT DOESNT INVOLVE BODY CELL AND IS INVOLVING ANTIBODIES PRESENT IN BODILY FLUID"
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Jpw1097
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(Original post by Jshek)
so is this the whole story

Pathogen enters the body.

phagocytosis happens which present the antigen on the phagocyte

t cells come along with complementary shape that binds to the antigen. which allows it to clone into many t cells,
the clone t cells help to

1.) memory cell
2.) stimulate phagocytes to pathgoen
3.) stimulate b cells tO divide and secrete antibodies
4.) cytotoxic cells which kill the infected cells

SO IF THE ANTIGEN ENTERS THE BLOOD STREAM, IT IS HUMORAL RATHER THAN CELL MEDIATED BECAUSE IT DOESNT INVOLVE BODY CELL AND IS INVOLVING ANTIBODIES PRESENT IN BODILY FLUID

ANTIGEN TAKEN UP BY B CELL

HELPER T CELL ATTCH TO ANTIGEN

ALLOWING B CELL TO DIVIDE BY MITOSIS TO GIVE PLASMA CELL..... antigen antibody complex


is it correct? im not sure if this bit is right "SO IF THE ANTIGEN ENTERS THE BLOOD STREAM, IT IS HUMORAL RATHER THAN CELL MEDIATED BECAUSE IT DOESNT INVOLVE BODY CELL AND IS INVOLVING ANTIBODIES PRESENT IN BODILY FLUID"
Both cell-mediated and humoral immunity will be happening at the same time, each strand of the immune system will activate the other, and so they do not happen separately, but they happen at the same time.
Helper T cells (cell-mediated) activate B cells causing them to secrete antibodies (humoral). B cells are also professional antigen presenting cells - this means when a pathogen binds to its B cell receptor, it also acts as a phagocyte. It engulfs the pathogen, digests it and presents antigens on its surface. This then activate helper T cells which stimulates a cell-mediated response.
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Jshek
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(Original post by Jpw1097)
Both cell-mediated and humoral immunity will be happening at the same time, each strand of the immune system will activate the other, and so they do not happen separately, but they happen at the same time.
Helper T cells (cell-mediated) activate B cells causing them to secrete antibodies (humoral). B cells are also professional antigen presenting cells - this means when a pathogen binds to its B cell receptor, it also acts as a phagocyte. It engulfs the pathogen, digests it and presents antigens on its surface. This then activate helper T cells which stimulates a cell-mediated response.
in my book it says the b cells are humoral immunity, that is immunity involving antibodies in bodily fluid and cell-mediated involves body cell. so does that mean when t cells bind to antigen (cell mediated) it stimulate antibodies that form antigen antibody complex in the body fluid? and happening in the same time
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Jshek
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(Original post by Jshek)
in my book it says the b cells are humoral immunity, that is immunity involving antibodies in bodily fluid and cell-mediated involves body cell. so does that mean when t cells bind to antigen (cell mediated) it stimulate antibodies that form antigen antibody complex in the body fluid? and happening in the same time
i just dont get the body cell and body fluid
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Jpw1097
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(Original post by Jshek)
in my book it says the b cells are humoral immunity, that is immunity involving antibodies in bodily fluid and cell-mediated involves body cell. so does that mean when t cells bind to antigen (cell mediated) it stimulate antibodies that form antigen antibody complex in the body fluid? and happening in the same time
I’m not quite sure what you’re asking.
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Jshek
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(Original post by Jpw1097)
I’m not quite sure what you’re asking.
Why do we need antibodies if the cytotoxic cells kills the infected cell. Is it because the antibodies are for the humoral immunity e.g antibodies in blood fluid
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Jshek
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(Original post by Jshek)
Why do we need antibodies if the cytotoxic cells kills the infected cell. Is it because the antibodies are for the humoral immunity e.g antibodies in blood fluid
Is it so that the antigens in blood stream are binded onto by antibodies as it is humoral
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(Original post by Jshek)
Why do we need antibodies if the cytotoxic cells kills the infected cell. Is it because the antibodies are for the humoral immunity e.g antibodies in blood fluid
Cytotoxic T cells kill infected cells, whereas antibodies bind to pathogens in the bloodstream (amongst other things).

Antibodies are also important for antibody-dependent cellular cytotoxicity (ADCC). When antibodies bind to a pathogen, this targets the pathogen for destruction by natural killer (NK) cells.
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Jshek
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(Original post by Jpw1097)
Cytotoxic T cells kill infected cells, whereas antibodies bind to pathogens in the bloodstream (amongst other things).

Antibodies are also important for antibody-dependent cellular cytotoxicity (ADCC). When antibodies bind to a pathogen, this targets the pathogen for destruction by natural killer (NK) cells.
So does antigen presenting cell/vaccine infect the body cell (cell mediated) and bloodstream (humoral)
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