WESTERN BLOT

A Western Blot (immunoblotting)is an analytical technique used for detection of specific proteins. The protein from the sample is first separated according to size by SDS-PAGE (Polyacrylamide Gel Electrophoresis) and then transferred to a nitrocellulose or Polyvinylidene Fluoride (PVDF) membrane where they become immobilized. Then they are detected first by a specific primary antibody and then by enzyme linked secondary antibody. The enzyme linked to the secondary antibody forms a colored band after conjugation which shows the presence of specific protein. It is used as a confirmatory test in many medical diagnostic tests like HIV, because it gives information if a specific antibody is been secreted against the pathogen.