Immune system clarification

[virtualmaster999]

Hey all!

Could someone clear this up for me?

So Natural killer cells do not attack microorganisms directly, but instead attack virally infected cells, or tumors.

Can Killer T cells attack microorganisms directly? I know that they release perforin to attack foreign cells, or cells that have been infected, and helper T cells release antibodies which can bind to free floating antigens.

Thank you in advance!

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[510586]

I thought only macrophages and neutrophils phagocytize the pathogens while the natural killer cell's job was only to kill the actual cells. Hopefully someone can come clarify

 

[DAT Destroyer]

Hey all!

Could someone clear this up for me?

So Natural killer cells do not attack microorganisms directly, but instead attack virally infected cells, or tumors.

Can Killer T cells attack microorganisms directly? I know that they release perforin to attack foreign cells, or cells that have been infected, and helper T cells release antibodies which can bind to free floating antigens.

Thank you in advance!

Can Killer T cells attack microorganisms directly?
Yes
NKT cells can recognize self and foreign antigens. They can recognize antigens from Mycobacterium (organism that causes tuberculosis), as well as microbes causing intestinal inflamation.

 

[XZeRO]

Can Killer T cells attack microorganisms directly? I know that they release perforin to attack foreign cells, or cells that have been infected, and helper T cells release antibodies which can bind to free floating antigens.

Killer (cytotoxic or CD8+) T cells will attack cells that present MHC-I (self-MHC) loaded with foreign antigens. That means they will kill cells that are infected with intracellular pathogens or cells that are producing "weird" proteins ie. cancerous cells.

Hey all!
helper T cells release antibodies which can bind to free floating antigens.

Helper T cells do not release antibodies; B cells and more specifically their antibody pumping plasma cell counterparts release antibodies. Helper T cells can help promote this process though by releasing cytokines and/or directly interacting with B cells.

Hope this helps!

 

[virtualmaster999]

Killer (cytotoxic or CD8+) T cells will attack cells that present MHC-I (self-MHC) loaded with foreign antigens. That means they will kill cells that are infected with intracellular pathogens or cells that are producing "weird" proteins ie. cancerous cells.


Helper T cells do not release antibodies; B cells and more specifically their antibody pumping plasma cell counterparts release antibodies. Helper T cells can help promote this process though by releasing cytokines and/or directly interacting with B cells.

Hope this helps!

woops yeah I swapped helper T and B cells when I was in a rush making this earlier. Thanks!

 

[virtualmaster999]

Killer (cytotoxic or CD8+) T cells will attack cells that present MHC-I (self-MHC) loaded with foreign antigens. That means they will kill cells that are infected with intracellular pathogens or cells that are producing "weird" proteins ie. cancerous cells.


Helper T cells do not release antibodies; B cells and more specifically their antibody pumping plasma cell counterparts release antibodies. Helper T cells can help promote this process though by releasing cytokines and/or directly interacting with B cells.

Hope this helps!

and this means that they will attack not only infected cells and cancerous cells, but also viruses and bacteria correct?

 

[XZeRO]

and this means that they will attack not only infected cells and cancerous cells, but also viruses and bacteria correct?

By viruses and bacteria, I am assuming you mean extracellular pathogens? If so, there are other methods to kill these things, ie. opsonisation (Ab directed clearance), complement MAC, etc.

Each T cell is specific, and through clonal expansion, recognise and attack things with specific cell markers, known as MHC, that have been "loaded" with a peptide sequence. B-cells spewing out antibodies that disable the pathogens and "mark" them for clearance is a more well known method to address extracellular pathogens. T cells killing pathogens directly is not the first thing that comes to mind, especially given that viruses are not exactly "living", but having said this, never say never...

 

[virtualmaster999]

By viruses and bacteria, I am assuming you mean extracellular pathogens? If so, there are other methods to kill these things, ie. opsonisation (Ab directed clearance), complement MAC, etc.

Each T cell is specific, and through clonal expansion, recognise and attack things with specific cell markers, known as MHC, that have been "loaded" with a peptide sequence. B-cells spewing out antibodies that disable the pathogens and "mark" them for clearance is a more well known method to address extracellular pathogens. T cells killing pathogens directly is not the first thing that comes to mind, especially given that viruses are not exactly "living", but having said this, never say never...

Oh so they are programmed to kill specific infected cells that have specific markers on them?

 

[XZeRO]

Not necessarily "programmed"; more like born. It is a fairly complex process that requires more than a forum post to address. I would look up things like hypermutation, VDJ recombination, and clonal expansion, if you are interested.

 

[virtualmaster999]

Not necessarily "programmed"; more like born. It is a fairly complex process that requires more than a forum post to address. I would look up things like hypermutation, VDJ recombination, and clonal expansion, if you are interested.

I see I see. Well, thank you for your response, I appreciate it!