Immunoprecipitation is a technique in which an antigen is isolated by binding to a specific antibody attached to a sedimentable matrix. It is also used to analyze protein fractions separated by other techniques such as gel filtration or density gradient sedimentation. The source of antigen for immunoprecipitation can be unlabeled cells or tissues, metabolically or intrinsically labeled cells, or in vitro-translated proteins. This unit describes a wide range of immunoprecipitation techniques, using either suspension or adherent cells lysed by various means.Usually, plasmas transfected cells or natural cells are ideal sample for immunoprecipitation.
THP1 is a human monocytic cell line isolated from an acute monocytic leukemia patient. Usually, it is used to test leukemia cell lines in immunocytochemical analysis of protein-protein interaction, and immunohistochemistry.
These cells show a large, round, single-cell morphology.
They are derived from the peripheral blood of a 1 year old human male patient with acute monocytic leukemia. Some of their characteristics are: a. They have Fc receptor and C3b receptors and lack surface and cytoplasmic immunoglobulins.
b. They produce IL-1.
c. They stain positive for alpha-naphthyl butyrate esterase, produce lysozymes and are phagocytic (both for latex beads and sensitized erythrocytes).
d. They can restore the response of purified T lymphocytes to Con A.
e. They show increased CO2 production on phagocytosis and can be differentiated into macrophage-like cells using for example phorbol 12- myristate 13-acetate (commonly known as PMA or TPA).
THP-1 cells can also restore the response of purified T lymphocytes to Concanavlin A, show increased CO2 production on phagocytosis and can be differentiated into macrophage-like cells using for example DMSO. Growing orders are recommended due to difficulties that can be experienced during the initial start-up of this cell line.