Co60 Vitamin B12 Binding Capacity of Human Leukocytes

1. Mature neutrophilic leukocytes show the highest Co⁶⁰B₁₂ binding capacity.

2. Less mature granulocytes, "blast" forms and eosinophils have little or noCo⁶⁰B₁₂ binding capacity.

3. Disintegrated mature leukocytes from chronic myelocytic leukemia andpolycythemia vera show higher B₁₂ binding capacity than intact cells.

4. Mature leukocytes from patients with chronic myelocytic leukemia andpolycythemia vera show a two-phase B₁₂ curve suggesting specific and nonspecificbinding, similar to that observed in human serum.

5. Disintegration products from mature neutrophilic leukocytes probablycontribute largely to increased B₁₂ binding capacity of serum in chronic myelocyticleukemia and polycythemia vera.

Submitted on August 30, 1961 Accepted on October 17, 1961