What is ELISA?
ELISA stands for enzyme linked immunosorbent assay. An ELISA test measures the amount of antibodies produced against a specific antigen (in this case, human serum albumin). The test is performed using a sample of blood or other bodily fluid. Antibodies are proteins made by your immune system that recognize foreign substances such as bacteria, viruses, parasites, and even cancer cells. These antibodies attach themselves to the antigen, which is then detected with a special antibody. The higher the level of antibodies, the stronger your immunity.
What is western blot?
Western blotting, also known as immunoblotting, is a method used to detect and identify specific proteins. This method is often used in combination with ELISA. The patient’s blood serum or tissue extracts are separated by gel electrophoresis. The separated ingredients are then transferred to a membrane by electroblotting. In the next step, the membrane is incubated with specific antibodies that are capable of recognizing and binding to the desired target protein. After a washing step to eliminate any unbound antibodies, the membrane is incubated with a secondary antibody linked to an enzyme. This complex will emit signals that can be detected by an external detector such as a chemiluminescent enzyme immuno assay, or by autoradiography. Antibodies used in western blotting are highly specific. Thus, western blotting is a very sensitive method to detect a particular target protein.
What is the major difference betweenwestern blot and immunohistochemistry?
Immunohistochemistry (IHC) is a method used to identify the presence of proteins in a sample. IHC is used to detect cancer or other disease markers in body tissue. It is also used to identify the presence of allergens, infectious disease markers, or other antigens. In IHC, the target cells are first fixed to prevent them from moving or degrading. The target cells are then incubated with primary antibody or antibodies that bind to a specific antigen (such as HER2 in the case of ductal carcinoma). The complex of antibody and antigen is detected using a labeled secondary antibody. The signal is amplified using an enzyme such as HRP or DAB. The antigen is visualized by color change or by developing a film. In immunohistochemistry, a pathologist examines a sample of cells from a patient and determines the presence of disease markers. For example, if the pathologist detects HER2 in ductal carcinoma, the patient has a good prognosis because it means that there are still cancerous cells present. This method is popular because it is quick and relatively cheap. However, it cannot be used to detect proteins that are in low quantities or distributed diffusely throughout the cell (such as the case with HER2).
What is the major difference betweenELISA and western blot?
ELISA and western blotting are both used to detect the presence of specific proteins. The major difference between the two is that western blotting uses electrophoresis to separate proteins and then detects them using antibodies, while ELISA uses antibodies against a target antigen and labels these with enzymes.
What is chemiluminescence?
Chemiluminescence is a process of generating light from a chemical reaction. This process is used in immunohistochemistry to detect antigens or antibodies using an enzyme. The enzyme luciferase acts on a substrate 3-aminophthalhydrazide to produce light. A luminometer is used to detect the light and measure it. Chemiluminescence is a very sensitive detection method, as it can measure low concentrations of antigens or antibodies.
How does immunohistochemistry work?
Immunohistochemistry is a commonly used method in biology to identify the presence of specific proteins in cells or tissue. During immunohistochemistry, the sample is first prepared by applying a fixative such as formaldehyde or ethanol to stabilize the cells of interest. A sample is then cut thin and mounted on a slide using an aqueous mounting medium. The sample is then reacted with specific primary antibodies that detect a desired antigen. After exposing the sample to the primary antibodies, it is then incubated with a secondary antibody that binds to the primary antibody. After a final incubation step, the sample is then washed and exposed to a substrate. The substrate binds to any secondary antibody that remains unbound. Then, the substrate is exposed to an activator, which results in a color change. This color change indicates that the antigen or antibody was present in the sample. Antibodies can also be labeled with a radioactive element, which emits a signal. The signal can then be detected using an instrument such as a scintillation counter or a gamma counter. Antibodies can also be labeled with a fluorescent dye, which emits light of a certain wavelength. The light can then be detected using a special microscope designed for fluorescence.
What is a monoclonal antibody?
A monoclonal antibody (or Mab) is an antibody that is produced by a clone of cells that all produce the same antibody. Monoclonal antibodies are often used as experimental therapeutics to treat conditions such as cancer. They can be used alone or can be conjugated to toxins or radioactive materials for targeted cancer treatment.
What is the difference between a monoclonal antibody and a polyclonal antibody?
A monoclonal antibody is made from a single clone of cells, while a polyclonal antibody is made from many different clones of cells. The term “antibody” refers to a substance that is specifically produced by an animal’s immune system to target a specific antigen.
What are the steps involved in creating a monoclonal antibody?
The first step in creating a monoclonal antibody involves immunizing an animal with the antigen of interest. The second step involves harvesting the B-cells of that animal’s immune system. Then, the B-cells are fused with a myeloma cell from a different animal to create a clone or “hybridoma” that produces antibodies of that particular animal against that specific antigen. The supernatant of this hybridoma is the desired monoclonal antibody.
What is a flow cytometer?
A flow cytometer is an instrument that can “count” the number of cells that pass through a laser beam by measuring the amount of fluorescent light emitted by each cell. It is often used in immunohistochemistry to count the number of cells that are labeled with a particular antigen.
What is chemotaxis?
Chemotaxis is the directed movement of an organism in response to a chemical stimulus. Chemotactic molecules, which are often called “chemoattractants” or “chemotaxins,” are molecules that can diffuse through the environment and activate receptors on the surface of cells. These receptors are transmembrane proteins that alter the behavior of the cell. The altered cellular behavior causes the cell to “move” in a certain direction according to the initial orientation of the receptor.
What is a chemokine?
A chemokine is a type of small cytokine (a category of signaling proteins) that regulates the migration of cells. Chemokines are produced by immune system cells and cause the directional movement of other immune system cells. They are important in the immune system’s response to pathogens such as bacteria and viruses that can cause disease.
What is a cytokine?
A cytokine is a type of signaling protein that transmits information between immune system cells. It is secreted by one cell and then binds to a specific receptor on the surface of another cell.
What is the difference between an agonist and an antagonist?
An agonist is a substance that binds to and activates a cell surface receptor. An antagonist is a substance that binds to and blocks a cell surface receptor.
What are the three types of cytokine receptors?
The three types of cytokine receptors are the tyrosine kinase receptor, the jnkinase receptor, and the enzyme-linked transmembrane. The first type allows the cytokine to directly activate a signal inside the cell by transferring phosphate molecules to a specific tyrosine amino acid on the receptor. The second type activates a G-protein which in turn starts a signaling cascade that leads to a cellular response. The third type is similar to the second type in that it involves a signaling cascade, but the mechanism is different.
What is an epitope?
An epitope is the part of an antigen that can bind to the paratope (a region on the surface of an antibody) and thus produce a potential immune response. The epitope is made up of a short amino acid sequence of between 3 and 20 amino acids. This sequence is recognized by the paratope of the antibody.
What is a hapten?
A hapten is a small molecule that cannot stimulate an immune response by itself. It requires a carrier, which is usually a larger protein, to which the hapten has been bonded. The carrier carries the hapten into the body and also brings along the hapten-carrier complex to which the body develops an immune response.
What is the purpose of interleukins?
Interleukins are cytokines that are made and released by one immune cell and act on other immune cells. They are mainly responsible for coordinating the activities of the various cells in the immune system.
What type of cells are leukocytes?
Leukocytes are one of the types of white blood cells.
Sources & references used in this article:
- Expression of HER-2/neu oncoprotein in human breast cancer: a comparison of immunohistochemical and western blot techniques. (R Molina, DR Ciocca, AK Tandon, DC Allred… – Anticancer …, 1992 – ncbi.nlm.nih.gov)
- Comparison of immunohistochemistry and two rapid tests for detection of abnormal prion protein in different brain regions of sheep with typical scrapie (R Bolea, E Monleón, I Schiller… – Journal of …, 2005 – journals.sagepub.com)
- Detection of IDH1 mutation in human gliomas: comparison of immunohistochemistry and sequencing (S Takano, W Tian, M Matsuda, T Yamamoto… – Brain tumor …, 2011 – Springer)
- Gonadotropin releasing hormone receptor expression in primary breast cancer: comparison of immunohistochemical, radioligand and Western blot analyses (A Mangia, S Tommasi, SJ Reshkin… – Oncology …, 2002 – spandidos-publications.com)