Antigen-antibody complexes, removal

The Complement System Facilitates Removal of Microorganisms and Antigen-Antibody Complexes The Cell-Mediated Response A Separate Response by T Cells... 

EL-4 cells (3 x 10 ) were lysed with N,N-dimethyl-N-(3-sulfopropyl)-3-[[(3a,5 P,7a, 12a)-3,7,12-trihydroxy-24-oxocholan-24-y 1]-amino]-l-propanaminium hydroxide (CHAPS). The nuclei and membranes were pelleted and the supematent lysate filtered to remove lipids. The lysate was sequentially passed over sepharose columns containing a) normal mouse serum b) Y-3 which is an anti-K monoclonal antibody. Both columns were washed with 45 coliunn volumes of progressively lower molarity salt solutions. The beads were then treated with acetic acid to release antigen-antibody complexes and the complex was denatured by boiling in 10% acetic acid. The mixture was filtered through a 3 kDa pore-size membrane and the filtrate containing MHC class I peptides subjected to reversed phase HPLC. 

Wash to remove unbound antigen. Antibody and free antigen-antibody complex Add enzyme specific substrate... 

Immune complexes (IC). Antigen-antibody complexes formed every time antibody meets antigen. May become pathogenic by triggering a variety of inflammatory processes if not removed effectively from circulation or if formed in situ. Immune complexes play a role in vasculitic manifestations of autoimmune diseases (e.g. lupus nephritis). 

One function of antibodies is to mop up free antigen and cause the antigen/ antibody complex produced to be removed from the system, normally by phagocytic cells. It is important to consider the kinetics of antigen and antibody appearance and disappearance when dealing with antibody responses to infectious disease agents. 

After formation of the antigen-antibody complex, and removal of excess of reagents, light was produced by reacting the complex with microperoxidase / hydrogen peroxide, or lactoperoxidase/hydrogen peroxide (the latter oxidative system was used only in the biotin chemiluminescent immunoassay). 

Fig. 9.18. Effects due to the interaction between a RAM phase and a mixture an antibody (Y shaped), antigen (triangle) and labelled antigen (triangle + star) (a) the phase traps small analyte and tracer molecules by mixed effects, i.e., size exclusion and hydrophobic interactions (b) if the hydrophobic forces are strong enough, the phase removes the tracer/anal5rte from their antibody complexes (c) the free antibody binds to free anal Tte/tracer previously trapped by the RAM phase.

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