a question about immunity sac tomorrow???????

[forchina]

I'm also doing a poster which everyone else seems to be doing. So this is my question:
Does 2nd line of defence always involve inflammation what ever the infection?
If the pathogen is not killed in the inflammation process, then in preceeds to the 3rd LOD.
Is this right?

[zhe0001]

I'm also doing a poster which everyone else seems to be doing. So this is my question:
Does 2nd line of defence always involve inflammation what ever the infection?
If the pathogen is not killed in the inflammation process, then in preceeds to the 3rd LOD.
Is this right?

Also doing Bio 3/4 this year.
This is in my opinion, so it may not be right.
But I believe that as the second line of defence is not specific and how inflammation is a reaction to the infection it will happen regardless of what type of infection it is.

Edit: If the pathogen is not killed off, there are of course other options, such as complement proteins and interfeons that the second line of defence is able to use. However, if the second level of defence fails, only till then does it proceed to the 3rd LOD

[ealam2]

Correct me if I'm wrong, but to my understanding once a pathogen crosses the barriers of the first line of defence, second and third line of defence happen simultaneously. It's just that third line of defence is slower due to the B cells having to find the matching antigen to undergo clonal expansion and produce antibodies from plasma cells and memory cells.

[forchina]

Edit: If the pathogen is not killed off, there are of course other options, such as complement proteins and interfeons that the second line of defence is able to use. However, if the second level of defence fails, only till then does it proceed to the 3rd LOD

Aren't complement proteins part of the inflammation process? And interferons can only be secreted by virus infected cells, right?

[zhe0001]

Aren't complement proteins part of the inflammation process? And interferons can only be secreted by virus infected cells, right?

I thought that too, but my nature of biology doesn't say anything about complement proteins so that's why I added it. You would assume that as inflammation allows more phagocytes to the area that complement proteins would also be there, but once again it doesn't say in the book. But you are probably right! You're also right about the interferons only secreted for virus infected cells too.

[forchina]

haha thanks anyway for your input. good luck on the sac 

[Yacoubb]

Inflammation is the result of infection that is caused by for instance, breaking the skin through a cut. When this occurs, mast cells release histamine, a substance which results in the increased blood flow to the infected area. This is done because the blood vessels dilate and become wider, enabling an increased blood flow carrying phagocytes. The capillaries also become more permeable to allow for the phagocytes to leave the blood vessels and move to tissue that is affected. Meanwhile, these white blood cells are binding to, engulfing and destroying this foreign matter that has happened to cross the first line of defence. A scab forms because the phagocytes die after engulfing so many foreign particles; this forms the pus.

Complement proteins can be involved by, for instance, coating the foreign antigens with a substance that makes them for identifiable to phagocytes. They can stimulate and activate phagocytes to carry out their roles more effectively, or even induce lysis of cellular pathogens like bacteria.

Correct me if I'm wrong, but to my understanding once a pathogen crosses the barriers of the first line of defence, second and third line of defence happen simultaneously. It's just that third line of defence is slower due to the B cells having to find the matching antigen to undergo clonal expansion and produce antibodies from plasma cells and memory cells.

^ That's what I was actually thinking. Because if say a macrophage engulfed a non-self antigen and then presented antigen fragments by class-2 MHC markers to Helper T-cells, that would go from the second line of defence as the macrophage engulfs the foreign antigen, and to then activate the humoral and cell-mediated response to destroy the foreign antigens and any traces of it.