Question

An antibody raised against an antigen can be used to determine the location of antigen in a cell using

• A. ELISA
• B. Gel diffusion
• C. Immunofluorescence light microscopy
• D. Immunoelectrophoresis

Hint:

In situ Antigen Localization $\rightarrow$ Immunofluorescence Microscopy Immunohistochemistry (IHC). Solution Quantification $\rightarrow$ ELISA.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Immunocytochemistry and fluorescence microscopy visualize intracellular spatial localization of target antigens in fixed cells.

Step 2: Detailed Explanation:
1. Immunofluorescence Microscopy: Fluorescent dyes (fluorophores like FITC, rhodamine, Alexa Fluor) are conjugated to primary or secondary antibodies. When applied to permeabilized cells or tissue sections, the labeled antibodies bind specifically to their cognate antigens in situ, allowing precise spatial subcellular localization under a fluorescence or confocal microscope.
2. ELISA Immunoelectrophoresis Gel Diffusion: Quantitative in vitro solution assays that measure antigen concentration in cell lysates, but destroy spatial cellular architecture.

Step 3: Final Answer:
Therefore, spatial location in a cell is determined using Immunofluorescence light microscopy, corresponding to option (C).