Functional heterogeneity of human cord blood monocytes.
Human cord blood monocytes were separated into four different subpopulations by means of a discontinuous bovine serum albumin (BSA) gradient. Of the least dense, 31% were present in fraction A, 17% in fraction B and 13% in fraction C and of the most dense, 20% were in fraction D. The rest (17%) sedimented as a pellet, of which 93% were dead cells. The monocytes of fraction C (density greater than or equal to 1.070) demonstrated suppressor activity on in vitro antibody synthesis of maternal B cells. Fraction D (density greater than or equal to 1.075) monocytes enhanced antibody synthesis of maternal B cells compared with synthesis produced in a similar experiment with unfractionated monocytes. Addition of either fraction A or B monocytes to the mixed culture of T and B cells resulted in antibody production comparable to that produced by addition of unfractionated monocytes. The functional heterogeneity of the cord monocytes was assayed also by 2-deoxyglucose (2-DOG) uptake, a marker for immunological macrophage activation. Fractions A and D showed significantly higher 2-DOG transport than that of unfractionated monocytes; in contrast, fraction C showed a 50% reduction of 2-DOG uptake. Furthermore, in contrast to fraction D, fraction C possessed only minimal phagocytic activity (for antibody-coated sheep erythrocytes) and minimal hemoxygenase enzyme activity. These data demonstrate functional heterogeneity of cord blood monocytes.
D000917:Antibody Formation; D001402:B-Lymphocytes / Q000276:immunology; D002469:Cell Separation; D003847:Deoxyglucose / Q000378:metabolism; D005260:Female; D005312:Fetal Blood / Q000166:cytology*; D006801:Humans; D007074:Immunoglobulin G / Q000096:biosynthesis; D009000:Monocytes / Q000502:physiology*; D010587:Phagocytosis; D011247:Pregnancy
D007074:Immunoglobulin G; D003847:Deoxyglucose