How does the cells of the innate immunity gets rid of the pathogens? - (Nov/19/2005 )

Hi. Can someone please explain to me what happens when a pathogen enters the body (eg. when you cut yourself)? Is the first step phagocytosis of the microbe by the macrophages, follow by chemotaxis and inflamation?

Hope someone can clear my doubts as I'm quite new in this area of study. Thanks

well, long before phagocytosis, there are other things that happen

and, chemotaxis and inflammation do not necessarily require phagocytosis

first of all, inflammation is probably already occurring if you cut your self

complement would be a factor in this example as well

cytokines and chemokines are involved in chemotaxis and inflammatory signalling events; defensins, and other antimicrobial peptides (lysozyme, LL-37, others) are all involved in pathogen destruction; signalling can also occur via binding to 'non-immune system' host cells

for example, peptidoglycan from staphylococcus aureus can function as a ligand for toll-like receptor 2 in epithelial keratinocytes, causing a signalling cascade within the keratinocyte cell that can lead to localized increase in cytokines and anitmicrobial peptides, long before macrophages, T cells, and B cells really have a chance to get involved. this is how the innate and adaptive immune systems function together


did I help, or just make the waters more muddy? I can give you a link to an abstract with a good review of how these systems work together, if that would help...I cannot send you a pdf but I can get you a good link

Thanks! But can u attach the link in to give me a better understanding? Also, how do u link the complement system to the process of ridding pathogens?

here is an answer to your complement question, in more detail that I know from the top of my head:

http://microvet.arizona.edu/Courses/MIC419...complement.html

And, for a review, I would choose this one; it is very current and provides a nice clear discussion. hopefully you have access to this journal?


J Invest Dermatol. Oct 2005. 125(4) p629-637. author, R Clark


I study this stuff, so if you have silly questions you can feel free to ask anytime

sometimes I might even know the answers

good luck

hi,
if you can ask the question more specific it will be easy to answer.
in regard to your question, when you cut your self means, there is blood flow so immune cell in blood flow will take care of entered pathogens and coagulation system will get activated and forms clotting.

coming chemotaxis in specifically, movement of any cell, in response to chemical gradient. quite often you will find in tissue system.
for example, in HIV disease monocytes are capable of crossing the blood vessels to the brain it is called as blood brain barrier. where as in atherosclerosis (cardiovascular disease) monocytes, lymphocytes and other cell types pass the blood vessel and finally cross the barrier and forms plaque. these two examples belongs to same system.

where as in agiogenesis, endothelial cells has to move(multiply and expand) to form new blood vessels, and during embryonic developemnt cells will differentiate and finally reach to their repective positions for proper developement.

if you look at the mechanism behind chemotaxis, it is complex process, it requires wide veriety of protein mechinary like, receptor, singnalling molecules, regulation of actin binding molecules, actin polymerization and depolymerization and formation of focal adhesion and so on.
you will find alot of literature on cell movement.

gud luck