Serum Complement Assay Method.

In the typical immune response, antibodies in the blood stream attach to invading disease bacteria and mark them as a foreign material that has to be destroyed. The complement activity attacks the bacteria that have been previously marked by antibodies for destruction by attaching to the cell wall of the bacteria at a point adjacent to the place where the antibody is attached. The complment activity bores a hole through the cell wall causing the punctured bacteria to be destroyed. Objects of this invention are to provide a fast and inexpensive complement activity assay method to provide a complement activity assay method which is not dependent on an animal source for cells and to provide a reliable complement activity assay method by using standard materials and a standardized technique thereby making the assay reproducible. These and other objects are achieved by preparing marker encapsulated liposomes which contain antigen derivitized phospholipid within the liposome membrane. The liposomes are sensitized by incubating them with the appropriate antibody specific for the antigen derivitized phospholipid in the membrane. The sensitized liposomes are incubated with serum containing complement proteins. The complement proteins attach to the liposomes and puncture the membrane thereby releasing the marker from the liposome. The amount of marker released into the solution indicates the amount of complement activity in the serum.