A new look at basophils in mice

Area of Science:

• Immunology
• Cell Biology

Background:

• Mice are widely believed to lack sufficient basophils to exhibit cutaneous basophil hypersensitivity.
• This lack of basophils has been cited as the reason for their inability to express this immune response.

Purpose of the Study:

• To investigate the presence and frequency of basophils in mice.
• To determine if basophils are present in mouse peripheral blood, challenging existing assumptions.

Main Methods:

• Peripheral blood smears were analyzed from four mouse strains (C3H/He, DBA/2, C57BL/6, Balb/c).
• Analysis was conducted before and after foreign protein injections, a known method to induce basophilia.
• Cell counts focused on identifying and quantifying basophils.

Main Results:

• Basophils were detected in untreated C3H/He (0.2%) and DBA/2 (1.5%) mice; none were found in untreated C57BL/6 and Balb/c mice.
• Following foreign protein injections, basophilia (2-10% basophils) was observed in all four mouse strains.
• Mouse basophils exhibited a distinct microscopic appearance compared to basophils from other species.

Conclusions:

• Mice possess detectable levels of basophils, comparable to humans and guinea pigs.
• The unique morphology of mouse basophils may have led to their underdetection in previous studies, potentially explaining the perceived absence of cutaneous basophil hypersensitivity.
• Further research is warranted to explore the functional role of these basophils in mouse immune responses.