Neonatal T4+ lymphocytes: analysis of the expression of 4B4 and 2H4 antigens.

Using monoclonal antibodies anti-2H4 and anti-4B4 we investigated by double immunofluorescence and immunorosette technique the presence of cells displaying the helper-inducer and the inducer of suppression phenotype among T4+ cord blood cells. The analysis of the estimated frequencies of subpopulations of T4+ cells shows that a high percentage of T4+ cord blood cells can coexpress both antigens in comparison to adult. Furthermore the percentage of T4+ cells with helper-inducer phenotype (2H4-4B4+) is significantly lower than that in the adult, while the percentage of T4+ cells with suppressor-inducer phenotype (2H4+4B4-) although higher, is not significantly different. These findings suggest that the relative immunoincompetence observed in the newborn may result from a variety of mechanisms including a low percentage of helper-inducer (4B4+2H4-) T4+ lymphocytes possibly also associated to an increased number of suppressor-inducer T4+ cells (2H4+4B4-).