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.
MCF-7 cells was first isolated in 1970 from the breast tissue of a 69-year old Caucasian woman. Of the two mastectomies she received, the first revealed the removed tissue to be benign. Five years later, the second operation revealed malignant adenocarcinoma in a pleural effusion from which was taken cells for MCF-7. The woman was treated for breast cancer with radiotheraphy and hormonotherapy. MCF 7 is a human breast adenocarcinoma cell line and has been used geneally in research, these cells were used in seminal studies on the estrogen receptor. A xenograft mouse model of MCF-7 breast cancer is used in studies to monitor cancer progression (MCF7 Xenograft Models). MCF 7 cells are cultured normally until they are confluent, but are then surgically implanted into a mouse's mammary fat pad. The size of tumor then can be assessed as the disease progresses.
MCF-7 cells are useful for in vitro breast cancer research because the cell line has several ideal characteristics particular to the mammary epithelium. These include the ability for MCF-7 cells to process estrogen, in form of estradiol, via estrogen receptors in cell cytoplasm. This makes the MCF-7 cell line an estrogen receptor (ER) positive control cell line.