phagocitosis non spefific?? (1 Viewer)

[Tim035]

Umm why is phagocitosis non spefific? according to my understanding the antigens on cell membranes tell the macrophages what to attack and what not to.. So doesn't that make it spefific?

 

[+Po1ntDeXt3r+]

macrophages can be activated by TCells to be specific...

but in initial interaction they can respond to non-specific triggers such as bacteria components (like the lipopolysaccharides, flagellin, unmethylated CpG nucleotides)... can initiate the phagocytosis..

macrophages can then present these phagocytosed antigens (bacterial specific protein) to the T-Cells.. which then activates a stronger more specific activation of other macrophages..

this is prolly more than the HSC bio syllabus requires.. but i dunno.. i didnt do bio =(.. however it is the answer.. Macrophages play a role in both innate and adaptive immunity

 

[simplistic]

so like isnt there a reaction between the mhcII and the antigenn and the macrophage which stimulates the production of helper t cells ?

 

[Survivor39]

Macrophages can essentially "present" antigen to T cells and tell T cells "this is the antigen you need to attack". But this process is "rare" because in most of the time, antigen presentation is carried out by a cell called "dendritic cell".

To the original response "Umm why is phagocitosis non spefific? according to my understanding the antigens on cell membranes tell the macrophages what to attack and what not to.. So doesn't that make it spefific?"

It is non-specific because macrophages recognise groups or classes of antigen. For example, they recognise all bacteria that has this type of sugar or protein. In the adaptive immunity, T and B cells are specific because they recognise SPECIFIC antigen - one antigen. Therefore, they don't just reconigse any antigen, this antigen must have this sequence or it won't be able to recognise it.

I hope this clarifies things.