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.
SH-SY5Y is a human derived cell line used in scientific research. The original cell line, called SK-N-SH, from which it was subcloned was isolated from a bone marrow biopsy taken from a four-year-old female patient with neuroblastoma. SH-SY5Y cells are often used as in vitro research models of neuronal function and differentiation. They are adrenergic in phenotype but also express dopaminergic markers and, as such, have also been used to study Parkinson's Disease.
SH-SY5Y has a dopamine-β-hydroxylase activity and can convert glutamate to GABA. It will also induce tumors in nude mice in around 3–4 weeks. The loss of neuronal characteristics has been described with increasing cell passage. Therefore it is recommended not to be used after passage 20 or verify specific characteristics such as noradrenalin uptake or neuronal tumor markers.