Prolonged cryopreservation of human granulocytes

Area of Science:

• Immunology
• Cell Biology
• Cryobiology

Background:

• Granulocytes are crucial immune cells.
• Cryopreservation is essential for long-term storage of biological materials.
• Maintaining granulocyte function post-cryopreservation is vital for therapeutic applications.

Purpose of the Study:

• To evaluate the efficacy of cryopreservation for human granulocytes.
• To assess the impact of storage duration and phase (liquid vs. vapor) on granulocyte function.
• To determine the feasibility of cryopreserved granulocyte transfusion therapy.

Main Methods:

• Human granulocytes were isolated using dextran sedimentation.
• Cells were cryopreserved using controlled-rate freezing in dimethyl sulfoxide and autologous plasma.
• Samples were stored in liquid nitrogen (vapor or liquid phase) for up to 8 months.
• Cell recovery and bactericidal activity against Staphylococcus aureus were assessed.
• Transmission electron microscopy was used to examine cellular morphology.

Main Results:

• Mean cell recovery was 58% and mean bactericidal activity was 72% after storage.
• No significant decline in cell recovery or bactericidal activity was observed with prolonged storage (up to 8 months).
• Samples stored for over 8 months showed 73% cell recovery and 77% bactericidal activity.
• No advantage of liquid over vapor phase storage was detected.
• Electron microscopy revealed intact cell membranes and granules, with some nuclear changes.

Conclusions:

• Cryopreservation effectively maintains human granulocyte function for extended periods.
• Prolonged storage does not significantly impair granulocyte recovery or bactericidal capacity.
• Cryopreserved granulocytes show promise for transfusion therapy, offering a viable option for patients.