Immunology- B cells and T cells

Hello, just revising immunology for my AS biology test on thursday and I'm really unsure on how t cells and b cells are linked? Im using the AQA book. I thought that the T cells stimulate B cells to start dividing and produce antibodies but in another section the book says the surface antigens on invading pathogens are taken up B cells and then activated by T cells? Im confused, so do the APC's from phagocytosis bind to B cells and T cells? If someone could walk me through the responses step by step that would be great! :colondollar:

Reply 1

Issy :)

2

Original post by hp707

Hello, just revising immunology for my AS biology test on thursday and I'm really unsure on how t cells and b cells are linked? Im using the AQA book. I thought that the T cells stimulate B cells to start dividing and produce antibodies but in another section the book says the surface antigens on invading pathogens are taken up B cells and then activated by T cells? Im confused, so do the APC's from phagocytosis bind to B cells and T cells? If someone could walk me through the responses step by step that would be great! :colondollar:

Hi,
Basically, the reason it is so confusing is they have tried to simplify the immune system which is very, very complicated and therefore both the above statements are sort of true.
Anyway, for the exam, there are two types of T cell. T Helper cell and a T Killer Cell (which aqa helpfully just call T cell :wink:

). In the humoural response,the T Helper cell (with complementary antigens etc) binds to the APC. It releases cytokines that attract a B cell (again with complementary antigens etc). The B cell divides by clonal expansion to form memory cells and plasma cells. The plasma cells produce antibodies etc etc
In a cell-mediated response, it is just T killer cells :smile:

Reply 2

Issy :)

2

1. (Vaccine contains)antigen/attenuated/dead pathogen;
2. Microfold cells (APC) take up/bind andpresent/transport antigen (toimmune system/lymphocytes/Tcells);
3. T-cells activate B-cells;
4. B-cells divide/form clone/undergomitosis;
5. B-cells produce antibodies;
6. Memory cells produced;
7. More antibodies/antibodiesproduced faster in secondaryresponse/on reinfection;

From 2014 past paper mark scheme :smile:

This is what the exam board wants

Reply 3

hp707

OP

10

Original post by Issy :)

1. (Vaccine contains)antigen/attenuated/dead pathogen;
2. Microfold cells (APC) take up/bind andpresent/transport antigen (toimmune system/lymphocytes/Tcells);
3. T-cells activate B-cells;
4. B-cells divide/form clone/undergomitosis;
5. B-cells produce antibodies;
6. Memory cells produced;
7. More antibodies/antibodiesproduced faster in secondaryresponse/on reinfection;

From 2014 past paper mark scheme :smile:

This is what the exam board wants

thankyou!! yes its very confusing :confused:

Reply 4

hp707

OP

10

Original post by Issy :)

1. (Vaccine contains)antigen/attenuated/dead pathogen;
2. Microfold cells (APC) take up/bind andpresent/transport antigen (toimmune system/lymphocytes/Tcells);
3. T-cells activate B-cells;
4. B-cells divide/form clone/undergomitosis;
5. B-cells produce antibodies;
6. Memory cells produced;
7. More antibodies/antibodiesproduced faster in secondaryresponse/on reinfection;

From 2014 past paper mark scheme :smile:

This is what the exam board wants

this is what I've done in my notes, would it be correct?-
Primary response- Pathogen detected —> phagocytes engulf producing APC’s —> receptors on t helper cells fit exactly onto these antigens and stimulate other T cells to divide rapidly by mitosis into cells. —> Cloned T cells, memory, stimulate more phagocytes, stimulate B cells to divide, t killer cells kill infected cells—> B cells divide by mitosis, plasma cells produce complementary antibodies to pathogens, antibodies attach to antigens and destroy them.
Secondary response- Some b cells develop into memory cells, respond to future infections by same pathogen by dividing rapidly and developing into plasma cells that produce antibodies.

Reply 5

Issy :)

2

Not sure I would use the highlighted wording below. Maybe something like the receptors on the T Helper Cell are complementary to the antigens on the APC. Induced fit model implies they are not automatically a 'perfect' fit but become better over time :smile:

Original post by hp707

this is what I've done in my notes, would it be correct?-
Primary response- Pathogen detected —> phagocytes engulf producing APC’s —> receptors on t helper cells fit exactly onto these antigens and stimulate other T cells to divide rapidly by mitosis into cells. —> Cloned T cells, memory, stimulate more phagocytes, stimulate B cells to divide, t killer cells kill infected cells—> B cells divide by mitosis, plasma cells produce complementary antibodies to pathogens, antibodies attach to antigens and destroy them.
Secondary response- Some b cells develop into memory cells, respond to future infections by same pathogen by dividing rapidly and developing into plasma cells that produce antibodies.

Reply 6

hp707

OP

10

Original post by Issy :)

Not sure I would use the highlighted wording below. Maybe something like the receptors on the T Helper Cell are complementary to the antigens on the APC. Induced fit model implies they are not automatically a 'perfect' fit but become better over time :smile:

good point, thanks!

Immunology- B cells and T cells

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