Which dye is used to stain basophils?

Basophils are a type of white blood cell that play a critical role in the immune response, particularly in allergic reactions and the response to parasitic infections. They are characterized by their large granules which stain darkly when specific dyes are used.

The correct answer constitutes the use of a basic dye. Basic dyes, such as methylene blue or toluidine blue, have a positive charge and are attracted to the negatively charged components of the basophil's granules, which contain substances like histamine and heparin. This affinity allows the granules to take on a pronounced coloration, making basophils identifiable under a microscope.

In contrast, acidic dyes would not effectively stain basophils, as they usually bind to positively charged components and therefore would not interact with the granules. Neutral dyes would also not provide the appropriate environment for staining, as they lack specific charge interactions that could facilitate clear visibility of basophils. The option stating that no dye is used is incorrect because dyes are critical for highlighting cellular features in histological examinations. Thus, the use of a basic dye is essential for visualizing and studying basophils effectively in laboratory settings.