Primary Antibody Structure & Function
Primary antibodies, a subgroup of immunoglobulins known as glycoproteins, specifically bind to one antigen or protein with high affinity. This is not to be confused with a secondary antibody, which binds to another (primary) antibody that is linked to another molecule.
Primary antibodies are extremely useful for detecting disease biomarkers in cancer, diabetes, Parkinson′s and Alzheimer′s disease. One example of such uses is with Pharmacokinetics, the study of how an organism affects a drug (e.g. digestion and metabolization). Here, antibodies are used for ADME (absorption, distribution, metabolism, and excretion) and testing multi-drug resistance (MDR).
Monoclonal and Polyclonal Antibodies
Mice, rats, and goats are used to produce primary antibodies, which are either polyclonal (pAb) or monoclonal (mAb). Polyclonal antibodies are derived from different B-cell lineages, thus producing a mixture of antibodies with varying levels of affinity which target multiple epitopes. Monoclonal antibodies are sourced from one B-cell lineage, thus producing highly specific antibodies with only one antibody subtype.
Use in Cell Biology
Primary antibodies are key components in cell biology for processes such as:
cell cycle progression
cytoskeleton and extracellular matrix (ECM) organization
protein synthesis and degradation
enzyme phenotype profiling
ion channel transport
Use in Gene Expression
Primary antibodies are useful in monitoring gene expression as part of detection systems which use a broad range of markers including b-galactosidase, biotin, digoxin, and DNP.
Other systems make use of protein fusion tags. These can consist of: alkaline phosphatase, FLAG, glutathione-S-transferase (GST), hemagglutinin (HA), maltose binding protein (MBP), c-myc, polyhistidine, thioredoxin, and peroxidase.
Primary antibodies can also monitor changes in phenotypes and status of the proteasome under normal and diseased conditions.
Leukocyte antigen and cytokine expression can also be measured; CD antigens (a type of leukocyte antigen) can help distinguish cell lineage, and functional subsets including:
human leukocyte (HLA) antigens (histocompatibility antigens (glycoproteins)
tumor necrosis factor (TNF)
Concentration and Modification Measurement
Aside from detection, primary antibodies can also be used to measure concentration changes as well as specific modifications such as phosphorylation, methylation, or glycosylation. This allows for the study of proteins which are activated, silenced, processed or causing disease.