Abstract
We studied the response of adult peripheral and cord blood mononuclear cells (MNCs) to graded concentrations of phytohemagglutinin (PHA) to characterize the requirements for proliferation and interferon-γ (IFN-γ) production. As the concentration of PHA was decreased, the proliferative response of both adult and cord blood MNCs decreased in parallel. At high concentrations of PHA (a: 120) cord blood MNCs display normal high proliferation but IFN-γ production was greatly diminished compared with adult MNCs. Addition of the calcium ionophore, A23187, to PHA-stimulated adult MNCs had no effect on proliferation or IFN-γ production at any of the concentrations of PHA tested. Furthermore, A23187 alone had no effect on proliferation or IFN-γ secretion. Similarly, the addition of A23187 to PHA-stimulated cord-blood MNCs had no effect on proliferation. However, when A23187 was added to high dose (1:120) PHA-stimulated cord blood MNCs IFN-γ production increased to levels comparable with adult PHA-stimulated MNCs. A similar pattern of response was seen when exogenous calcium chloride was added in place of A23187.
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