SUPPRESSION OF B LYMPHOCYTES IN MATURE NEWBORN INFANTS |
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Authors: | S. A. PEDERSEN J. PETERSEN V. ANDERSEN |
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Affiliation: | Department of Neonatology GN and the Laboratory of Medical Immunology, Department of Medicine TA, Rigshospitalet, Copenhagen, Denmark |
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Abstract: | ABSTRACT. The ability of cord blood lymphocytes to secrete immunoglobulins during in vitro culture was investigated by means of a reverse hemolytic plaque forming cell (PFC) assay. Mononuclear cord blood cells did not differentiate into immunoglobulin-secreting cells after stimulation with the polyclonal B lymphocyte activator pokeweed mitogen (PWM), contrary to the findings in normal adults. Mononuclear cord blood cells were then separated into T-enriched and T-depleted blood lymphocyte subsets. When these were co-cultured, the PWM-induced immunoglobulin secretion was still low; following irradiation of the T-enriched cells, the numbers of IgM-PFC but not of IgG- or IgA-PFC increased considerably. The effect of irradiation of the T-enriched cells on the PWM-induced IgM response was dose-dependent, with maximal effect at 2500 rad. It is concluded that the low PWM responses obtained using cord blood lymphocytes are in part due to suppression by radiosensitive T suppressor cells. Following removal of this suppression by means of irradiation, B lymphocytes can be induced to secrete IgM, but not IgG or IgA. |
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Keywords: | Cord blood B lymphocytes IgM secretion T suppressor cells |
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