Human blood basophils display a unique phenotype including activation linked membrane structures

Area of Science:

• Immunology
• Cell Biology
• Hematology

Background:

• Basophils are a type of granulocyte with complex roles in immune responses.
• Understanding basophil surface marker expression is crucial for differentiating them from other myeloid cells and identifying their activation state.

Purpose of the Study:

• To comprehensively characterize the membrane marker profile of human basophils.
• To identify unique surface antigens expressed by basophils, potentially indicating activation.

Main Methods:

• Utilized a panel of 60 monoclonal antibodies (MoAbs) for combined toluidine/immunofluorescence staining.
• Analyzed basophil surface markers on cells in suspension and purified fractions, including those from chronic granulocytic leukemia (CGL) patients.
• Employed flow cytometry (FACS) for detailed analysis.

Main Results:

• Basophils express myeloid-associated markers (e.g., LFA-1 family, CDw17, CDw13, CDw12, VIM-2), indicating a relationship with other myeloid cells.
• Basophils uniquely express activation-linked structures (p45, p24, interleukin-2 receptor) not found on mature neutrophils.
• Under culture conditions, basophils express HLA-DR and T4 antigens; 3-fucosyl-N-acetyllactosamine is expressed after neuraminidase treatment.
• Basophils did not stain with MoAbs against Fc gamma-receptor (50-70 kd), CDw12, or CDw14, differentiating them from neutrophils and monocytes.

Conclusions:

• Human basophils possess a unique combination of surface determinants.
• Basophils may represent an inherently activated cell population.
• The distinct marker profile aids in understanding basophil function and differentiation.