NO EVIDENCE OF AN INFLUENCE OF THE NONINHERITED MATERNAL HLA ANTIGENSON THE ALLOREACTIVE T-CELL REPERTOIRE IN HEALTHY-INDIVIDUALS

In order to test whether a selective T cell nonresponsiveness to nonin herited maternal human leukocyte antigens (NIM) exists, we measured th e frequencies of alloreactive T cells of healthy individuals to their NIM HLA antigens and to their noninherited paternal (NIP) HLA antigens by limiting dilution assays. Both the fr equencies of cytotoxic T cel l precursors (CTLp) and IL-2-producing helper T cell precursors (HTLp) were determined. Similar frequencies were observed for NIM class I-re active CTLp and NIP class I-reactive CTLp. This was the case when freq uencies were determined against total NIM and NIP haplotypes but also when CTLp frequencies against individual MM and NIP antigens were meas ured. A positive finding of this study was the confirmation of our ear lier observation that CTLp frequencies against individual HLA-A antige ns are generally lower than CTLp frequencies against HLA-B. This was f ound both for the maternal and the paternal HLA-A and -B antigens. Sim ilarly, comparable frequencies of IL-2-producing helper T cell precurs ors directed against NIM HLA class II antigens and NIP HLA class II an tigens were found. When breast-feeding in the neonatal period was cons idered, no differences in the frequencies of CTLp and HTLp were observ ed between children who had been breast-fed and children who had not. Therefore the present data do not support the hypothesis that confront ation with noninherited maternal HLA in neonatal life leads to down-re gulation of alloreactive T cell responses to the mother.