Abstract
Cellular (T-cell) immunity in infants and young children is suspect because of diminished delayed skin tests and increased susceptibility to infection, engraftment, and malignancy. However, T cell numbers and proliferative responses are normal, and lymphokine production is variably reduced. We therefore studied two cytotoxic functions of T cells, natural killer (NK) and lect-in-dependent (LD) cytotoxicity in newborns, young children less than 24 months, and adults. In the PHA-enhanced LD cytotoxicity assay, whole mononuclear (MN), T enriched (>95% T cells) and T depleted (<1% T cells) fractions were tested against 51Cr-labeled EL-4 target cells in a 4 hour incubation at an effector target ratio of 40:1. In the NK assay, MN cells were used against 51Cr labeled Molt-4f tumor cells with and without the addition of exogenous interferon (100 units) at effector:target ratios of 50:1, 25:1, and 10:1. Cyclic AMP levels were also assessed in the cell fractions. In the LD assay, the MN cord blood cells had equivalent specific cytotoxicity (34 vs 32%, N=14) to adult cells but the T-enriched fractions had a strikingly decreased cytotoxicity (22 vs 51%) compared to adults. This normalizes after age 2. By contrast NK activity and interferon enhancement was equivalent in newborn and adult cells (53 vs 55%, N=10). Cyclic AMP levels of newborn cells were markedly reduced. These results indicate that NK maturation occurs very early, that an important T-effector function is immature in newborns, and that their T cells resemble those of some patients with T cell immunodeficiency.
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Lubens, R., Gard, S. & Stiehm, E. 943 T CELL EFFECTOR DEFICIENCY IN INFANTS AND YOUNG CHILDREN. Pediatr Res 15 (Suppl 4), 599 (1981). https://doi.org/10.1203/00006450-198104001-00968
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DOI: https://doi.org/10.1203/00006450-198104001-00968