The antigen used in the flocculation test for syphilis is composed of which components?

The antigen used in the flocculation test for syphilis, specifically the Venereal Disease Research Laboratory (VDRL) test, is composed of cardiolipin and lecithin. This antigen is typically derived from an extract of beef heart and is used to detect the presence of reagin antibodies that are produced in response to the infection caused by Treponema pallidum, the bacterium responsible for syphilis.

Cardiolipin is a phospholipid that plays a critical role in the structure of mitochondrial membranes and immune reactions. Lecithin, also a phospholipid, is often used as an emulsifier in various biological assays. These components together create an antigen that reacts with antibodies in the serum of patients with syphilis, forming visible flocculation.

This specific composition is vital for the test's sensitivity and specificity, allowing for a reliable diagnosis of syphilis. Other options listed involve components that are unrelated to the formation or function of the flocculation test's antigen in syphilis testing.