Antigen \ Antibody Interactions

[Fairy]

Hello Need help understanding some of my course work and i heard there is smart people here.
Can someone tell me what complement fixation is ( a simple defination ) in regards to antigen antibody reactions.
help

[victor]

Complement fixation, a series of ways that makes up chemie agents to opsonized antigens...activated during antigen interaction...divided in two: classic way and alternative way...

[reem]

u r asking in basic immunology

basiclly

when 2 IgG or 1 IgM bind or react with the epitope on the antigen complement C1 react with the antibody and start the complement cascade which lead to Ag membrane distruction

[Dr.Stein]

There are two ways on how complement system work.

First, by facilitating phagocytosis with opsonization. For instance, the big fragment of complement, C3b, will be bound on the antigen surface. Antibody will recognize this via its Fab. Phagocyte, macrophage and/or PMN has a receptor for Fc of Ig that will easily engulf antigen that already wrapped by complement+antibody.

Second, the smaller fragment of complement, C3a will dissolve into blood plasma and will act as an inflamatory mediator.

There is another one of how complement system work, this must be very nice to know, that they arrange to create a tunnel and make a hole on cell surface of bacteria. Eventually bacteria will burst out.

[Nite]

Complement fixation, a series of ways that makes up chemie agents to opsonized antigens...activated during antigen interaction...divided in two: classic way and alternative way...

there is a one more pathway of complement activation. The lectin pathway; where MBL(Mannose Binding Lectin):MASP complex bind to mannose on microbes and activate C4 and C2 in a similar fashion as the classic pathway..

*correction:p in red

[victor]

I think the burst out come from ROI mechanism....sorry to misunderstood your typing Dr.Stein...
@Nite
thanks for the information..and by the way, you live in Indonesia...what city do you live in?

[Dr.Stein]

I think the burst out come from ROI mechanism....sorry to misunderstood your typing Dr.Stein...

ROI? Err, remind me about that again, please...

The burst out process or pore-making activity is the result from "membrane-attack complex" (MAC) mechanism provided by terminal complement components: C5 (especially C5a), C6, C7, C8, C9.

I have couple nice figures for that

[victor]

ROI is an oxygen dependent lysis reaction...I think it's called Reactive Oxygen Intermediate.
The products of ROI is H2O2, ClO-, O2-, usw..

[Dr.Stein]

Nein. The burst out in this case (MAC) is not ROI mechanism. It's complement system activity as I mentioned above

[Fairy]

hey thanks for all the information it really helped

[Dr.Stein]

When you are happy, we are happy too *hugs*

[victor]

Nein. The burst out in this case (MAC) is not ROI mechanism. It's complement system activity as I mentioned above

that's why I said that I'd misunderstood your MAC writting..