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    • #3075
      Fairy
      Participant

      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 ❗

    • #36157
      victor
      Participant

      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…

    • #36277
      reem
      Participant

      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

    • #36430
      Dr.Stein
      Participant

      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.

    • #36563
      Nite
      Participant
      quote 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…

      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

    • #36567
      victor
      Participant

      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?

    • #36626
      Dr.Stein
      Participant
      quote victor:

      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 😉

    • #36742
      victor
      Participant

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

    • #36828
      Dr.Stein
      Participant

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

    • #36847
      Fairy
      Participant

      hey thanks for all the information it really helped 😀 😀 😀

    • #36906
      Dr.Stein
      Participant

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

    • #36947
      victor
      Participant
      quote Dr.Stein:

      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.. 😆

    • #37032
      Dr.Stein
      Participant

      You’re forgiven 😀

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