Question

What is immunolabeling? How does this work for visualizing molecules in a cell? Does this method work on live cells, dead cells, or both?

Answer 1

Immunolabeling is a biochemical method (process) which allows the detection and the localization of an antigen to the required site (within a cell or tissue or organ). NOTE; Antigens are the organic molecules (normally the proteins) which are capable of binding to an antibody.

If there is a need to reveal the information about a a cell or its substructures, this process is termed as Immonocytochemistry.

Immonocytochemistry is a laboratory technique, which is used to anatomically visualize location of the specific protein or the antigen in the cell with the help of specific primary antibody which binds to it. The visualization of the protein is then allowed by the primary antibody under a floresence microscope.

There are two complex steps for immunolabeling in manufacture of the antibody, first being the producing the antibody which binds specifically to the antigen of the interest and the second is tag fusing to the antibody. Since it is impossible to fuse, a tag to every antigen-specific antibody, thus, most of the immunolabeling processes utilize the indirect method of detection. This method employs a primary antibody which is antigen-specific and a secondary antibody which is fused to the tag which exclusively (specifically) binds the primary antibody.

Tags may typically include: a florescent compound, gold beads, or an enzyme which produces a colored compound. The association of these tags to the target molecules via the antibodies gives the visualization and identification of the antigen of interest in its native location in the tissue (viz. cell membrane, nuclear membrane or cytoplasm).

Immonolabelling is generally done for the dead cells. However, in recent years researchers are also working to do it for live cells as well.