Surface coats on human lymphocytes: freeze-drying and staining with cations

Area of Science:

• Immunology
• Cell Biology
• Microscopy

Background:

• Human peripheral blood lymphocytes possess a surface coat.
• Previous studies reported a 40-65 nm amorphous extracellular material on fixed, freeze-dried lymphocytes.
• The nature of this material required further investigation.

Purpose of the Study:

• To characterize the extracellular coat on human peripheral blood lymphocytes.
• To determine if freeze-drying artifacts contribute to the observed surface material.
• To explore the potential of freeze-drying for assessing lymphocyte surface morphology and its relation to immune function.

Main Methods:

• Staining human peripheral blood lymphocytes with ruthenium red, alcian blue, Thorotrast, and cationized ferritin.
• Utilizing freeze-drying techniques for lymphocyte preparation.
• Employing X-ray microanalysis to investigate the composition of the extracellular material.

Main Results:

• Various stains demonstrated a surface coat on lymphocytes with a distribution consistent with a 40-65 nm amorphous extracellular layer.
• Evidence, including X-ray microanalysis, suggests the extracellular material is not a contaminant introduced by freeze-drying.
• Freeze-drying appears to preserve and allow morphological assessment of the lymphocyte extracellular coat.

Conclusions:

• The extracellular coat on lymphocytes can be visualized using specific staining methods and freeze-drying.
• Freeze-drying is a viable technique for studying lymphocyte surface morphology, including the extracellular coat.
• Understanding the lymphocyte extracellular coat may offer insights into the immune response.