Maximum folate binding in leukocyte lysates and sera from blood donors.

Maximum binding of [3H] folate was determined in leukocyte lysates and sera from blood donors with normal hematological parameters. The folate binding activity in leukocyte lysates showed a remarkably great interindividual variation, whereas the folate binding in sera from the same persons showed a rather modest interindividual variation. The folate binding activity in leukocyte lysates is mainly derived from granulocytes since lymphocytes and monocytes from individuals with high content of folate binder in their leukocytes contained less than 1% of the total binding activity.