order of immune response?

I'm confused as to the order of the response. like when hpagocytosis occurs, is the pathogen dead as it's been broken down yet antigens are presented? also after this do t cells always need a phagocyte to present the antgens to then bind and carry out it's role? and do b cells only function after t cells have bound to the antigen and have activated b cells?

Reply 1

Epitype

16

1. When phagocytosis is undergone, the pathogen is killed (lysed using lytic enzymes), and the antigens are presneted on the surface of the phagocyte.
2. A T-cell needs to bind its receptors to the antigens on the APC (antigen presenting cell, here being the phagocyte) in order to become activated and undergo mitosis to produce Helper T-Cells, Cytotoxic T-Cells, T-Memory Cells and Supressor T-Cells.
3. The B-Cells require the Activated T-Cells to also undergo mitosis to produce B-Plasma Cells and B-Memory Cells.

Reply 2

username3446470

OP

20

Original post by Epitype

1. When phagocytosis is undergone, the pathogen is killed (lysed using lytic enzymes), and the antigens are presneted on the surface of the phagocyte.
2. A T-cell needs to bind its receptors to the antigens on the APC (antigen presenting cell, here being the phagocyte) in order to become activated and undergo mitosis to produce Helper T-Cells, Cytotoxic T-Cells, T-Memory Cells and Supressor T-Cells.
3. The B-Cells require the Activated T-Cells to also undergo mitosis to produce B-Plasma Cells and B-Memory Cells.

thanks you so much for the reply. I'm confused as to why the phagocyte presents the antigens on its surface for th3 t cells and then b cells to come into play if the pathogen has already been destroyed?

Reply 3

Jm562

10

B-cells would have to come into play because there would be pathogens in the blood (or other body fluids such as tissue fluids). Its important B-cells also come into action before the pathogen enters the cell

Reply 4

Epitype

16

Original post by jonjoshelvey21

thanks you so much for the reply. I'm confused as to why the phagocyte presents the antigens on its surface for th3 t cells and then b cells to come into play if the pathogen has already been destroyed?

There isn't only one pathogenic cell, there are thousands and rapidly dividing.
Phagocytes will not kill every single pathogenic cell in the body; Phagocytosis is the start of an immune mechanism that works in co-ordination with Phagocytes, T-cells and B-Cells in order to eliminate all pathogenic cells.

Reply 5

username3446470

OP

20

Original post by Epitype

There isn't only one pathogenic cell, there are thousands and rapidly dividing.
Phagocytes will not kill every single pathogenic cell in the body; Phagocytosis is the start of an immune mechanism that works in co-ordination with Phagocytes, T-cells and B-Cells in order to eliminate all pathogenic cells.

thanks, but surely t cells require antigens to be presented to it?

Reply 6

Epitype

16

Antigens are presented TO (not on) the T-Cell by the Antigen Presenting Cell (Phagocyte).
The antigens are presented on the phagocyte, which then acts as an Antigen Presenting Cell. The Antigen Presenting Cell binds with an inactivated T-cell (which is specific to that pathogen) at the T-Cell's receptor, causing it to become activated. It then forms the other types of T-Cells. The activated T-Cell also binds with a specific inactivated B-Cell, which then activates it. It then goes off and forms its own cells.

Reply 7

username3446470

OP

20

Original post by Epitype

There isn't only one pathogenic cell, there are thousands and rapidly dividing.
Phagocytes will not kill every single pathogenic cell in the body; Phagocytosis is the start of an immune mechanism that works in co-ordination with Phagocytes, T-cells and B-Cells in order to eliminate all pathogenic cells.

sorry to be annoying but I'm still unsure in this. what's the point of t and b cells if phagocyte is the secondary response and non specific and kills the pathogen

Reply 8

Epitype

16

Original post by jonjoshelvey21

sorry to be annoying but I'm still unsure in this. what's the point of t and b cells if phagocyte is the secondary response and non specific and kills the pathogen

Having B-Cells would produce B-Plasma cells, which secrete specific Antibodies. These would make Phagocytosis much easier and quicker (through processes such as Agglutination), and they also act as markers for phagocytes to find pathogenic cells. B-Cells also produce B-Memory cells, which are long lasting and can rapidly produce more B-Plasma cells (and so antibodies) instantly upon a second exposure.
T-Cells produce Cytotoxic T-Cells, which help kill pathogenic cells through osmotic movement of water into a cell. This just speeds up the process of killing all the pathogenic cells. They also produce T-Memory cells, which produce more T-Cells upon secondary exposure.
This is the point of B and T-Cells; Speeding up eradication of pathogenic cells, and long-lasting immune defense against the pathogen. The Phagocyte cannot do any of these, they can only present antigens, which is required to activate T-Cells, and then B-Cells.

Reply 9

h lovibond

2

2 systems, Innate & Adaptive

Innate- Phagocytosis. Pathogen is broken apart to find out what's inside- presenting Antigens. (There's a number of cells that do this).

Adaptive- T-cells are presented with these antigens and become either T killer or T helper. T killer starts destroying pathogen. T helper activates B cells. B cells can also help destroy pathogen (Killer B) but mostly remain in the blood in case the pathogen is to return. Then they are able to quickly recognise the pathogen and destroy quickly. A good reason why we have vaccination.

order of immune response?

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