Process
The complement system is a system of serum proteins that react with antigen-antibody complexes. If this reaction occurs on a cell surface, it will result in the formation of trans-membrane pores and therefore destruction of the cell. The basic steps of a complement fixation test are as follows:
- Serum is isolated from the patient.
- Patients naturally have different levels of complement proteins in their serum. To negate any effects this might have on the test, the complement proteins in the patient's serum must be destroyed and replaced by a known amount of standardized complement proteins.
- The serum is heated in such a way that all of the complement proteins—but none of the antibodies—within it are destroyed. (This is possible because complement proteins are much more susceptible to destruction by heat than antibodies.)
- A known amount of standard complement proteins are added to the serum. (These proteins are frequently obtained from guinea pig serum.)
- The antigen of interest is added to the serum.
- Sheep red blood cells (sRBCs) which have been pre-bound to anti-sRBC antibodies are added to the serum. The test is considered negative if the solution turns pink at this point and positive otherwise.
If the patient's serum contains antibodies against the antigen of interest, they will bind to the antigen in step 3 to form antigen-antibody complexes. The complement proteins will react with these complexes and be depleted. Thus when the sRBC-antibody complexes are added in step 4, there will be no complement left in the serum. However, if no antibodies against the antigen of interest are present, the complement will not be depleted and it will react with the sRBC-antibody complexes added in step 4, lysing the sRBCs and spilling their contents into the solution, thereby turning the solution pink.
Read more about this topic: Complement Fixation Test
Famous quotes containing the word process:
“Language is a process of free creation; its laws and principles are fixed, but the manner in which the principles of generation are used is free and infinitely varied. Even the interpretation and use of words involves a process of free creation.”
—Noam Chomsky (b. 1928)
“The practice of S/M is the creation of pleasure.... And that’s why S/M is really a subculture. It’s a process of invention. S/M is the use of a strategic relationship as a source of pleasure.”
—Michel Foucault (1926–1984)
“A designer who is not also a couturier, who hasn’t learned the most refined mysteries of physically creating his models, is like a sculptor who gives his drawings to another man, an artisan, to accomplish. For him the truncated process of creating will always be an interrupted act of love, and his style will bear the shame of it, the impoverishment.”
—Yves Saint Laurent (b. 1936)