What is Western Blot?
The western blot (sometimes called the protein immunoblot) is a widely accepted analytical technique used to detect specific proteins in a given sample of tissue homogenate or extract. It uses gel electrophoresis to separate native proteins by 3-D structure or denatured proteins by the length of the polypeptide. The proteins are then transferred to a membrane (typically nitrocellulose or PVDF), where they are stained with antibodies specific to the target protein.
HIV AIDS has become a global problem and the incidence of this dreaded disease has increased alarmingly in the last few decades. There are many techniques for detecting the presence of the virus in the human body and two popular methods are ELISA and Western Blotting. There are many similarities in these two types of testing. However, there are also many differences.
What is ELISA?
It stands for enzyme linked immunosorbent assay, and was the first test designed primarily for HIV detection. ELISA is known for its high sensitivity. In this test, a patient’s serum is diluted greatly (400 times) and placed on a plate on which HIV antigens are already present. If the serum contains antibodies for HIV, they stick to these antigens. The plate is then washed to remove all other components of patient’s serum and another specially prepared antibody is applied to the plate. This antibody binds to human antibodies and is linked to an enzyme. A substrate for enzyme is applied and the colour change because of catalysis of enzyme gives out the results of the test. This test gives a qualitative result.