[neilep (OP)]

Dearest Science Peeps Of Academic Gravitas,


See the picture below ? A genuine non-doctored bona-fide picture of a real cell defending the body.









A genuine non-doctored bona-fide picture of a real cell defending the body as just mentioned in the above sentence just moments ago

How do the cells know where the infectious cells are ? and how do they even move to apprehend the the offending cells ? Do they ' uber' it ? use Waze ? ask directions ?  I dunno !!


Do ewe know ?

I went and asked a prisoner as he was inside a cell and he had no idea !!


Thank ewe for your kind service in shedding some light here.


Hugs

shmishes

mwah mwah

Neil
xxxxxxxx

Immune immune, you're not a cartoon
Defending the body from infectious doom
But how do you know where the enemy lies ?
And your method of travel what does it comprise ?

[Halc]

See the picture below ? A genuine non-doctored bona-fide picture of a real cell defending the body.

I noticed that.  It needs to fight the baddies (green and yellow ones) and not the blue toast that you ate a while ago, nor the purple tooth that you should have put under your pillow, nor the bewildered pink video game controller that entertains the warrior once he's done.

How do the cells know where the infectious cells are

Well, they come across them by accident. They sort of get everywhere since they ride the pipes. They find something with DNA that doesn't match them, and they resist it. Cancer isn't fought because the DNA looks OK to them.  The little lambs in their ewey mommys are alien, and the ewe needs to put out little local anti-rejection drugs at the placenta barrier to prevent rejection of the DNA of the lamb, because otherwise it would very much be smote.

Apparently they're not quick on the draw. They have to learn that something is bad, so they don't recognize it right away. This is why vaccines help. It kind of sends them all to school where they show pictures of the baddies to them and then they recognize them quicker when the real ones show up.

I think a slight variation on the question is, how do they stick around (in the current and all) when they find bad stuff. You see pictures of the white cells gathering their forces to battle some baddy. That means they can resist the current, and locomote to the scene, or at least to stay at the scene.  I have no answer to that, so I pose the question to subsequent posters.

[paul cotter]

Cells of the immune system find their target by the process of chemotaxis. This is where the gradient of certain signalling molecules indicates the direction of it's source much like tracing the source of a smell. The processes involved are quite complex involving the placing of markers on the surface of damaged or infected cells followed by complex messaging between macrophages, reticular cells and t lymphocytes. If a cell is infected by a virus, fungus or intracellular bacterium the final stage is the homing in of killer t lymphocytes, via chemotaxis, to destroy said cell. Free floating bacteria are dealt with by neutrophils and I think this is not directed, but I could be wrong.

[paul cotter]

An addendum re cancer and dna. Dna is generally well sequestered within a cell and is not "visible" to the immune system. What determines the "self" versus "nonself" is the cell surface antigens and sometimes these can reflect changes in dna. Some cancers involve alteration to the cell's dna: the Philadelphia chromosome occurs due to two genes being partially transposed resulting in a new combination, this leads to one of the leukemias . A lot of cancers occur due to the switching off of apoptosis genes. Apoptosis is programmed orderly cell death which may occur due to serious faults within the cell or simply that time has run out for that cell. In the absence of apoptosis rogue cells can multiply and cause chaos.