AFM detection of mitogen-induced morphological changes in human B lymphocyte

Area of Science:

• Immunology
• Cell Biology
• Biophysics

Background:

• B-lymphocyte activation is crucial for humoral immunity.
• Previous studies focused on in vivo and in vitro activation processes.
• Ultrastructural and adhesion property changes during B-lymphocyte activation were not well understood.

Purpose of the Study:

• To investigate the morphological and mechanical property changes of human peripheral blood B lymphocytes during activation.
• To analyze ultrastructural alterations and adhesion force variations in stimulated B lymphocytes.

Main Methods:

• Human peripheral blood B lymphocytes were treated with pokeweed mitogen (PWM) and Staphylococcus aureus Cowan strain I (SAC) for 24 hours.
• Atomic force microscopy (AFM) was employed to study changes in cell morphology and mechanical properties.
• Cell height, diameter, volume, membrane roughness, and adhesion forces were measured.

Main Results:

• B-lymphocyte stimulation by PWM and SAC led to significant changes in cell height, diameter, and volume.
• Ultrastructural analysis revealed protein aggregation on the B-lymphocyte membrane, increasing average roughness and particle height.
• Adhesion forces increased significantly in treated cells (304.16 ± 60.30 pN for PWM, 249.63 ± 58.03 pN for SAC) compared to controls (104.28 ± 21.77 pN).

Conclusions:

• B-lymphocyte activation induces distinct changes in cell morphology and membrane ultrastructure.
• Increased adhesion force is a key mechanical property change associated with B-lymphocyte activation.
• These findings offer novel insights into B-lymphocyte activation mechanisms and structure-function relationships.