[Genetic, immunological and functional studies on lymphocytes with OKT4-epitope deficiency]

Although it is well-known that Leu3a-epitope on CD4 molecule functions as a receptor for human immunodeficiency virus (HIV), the function of OKT4-epitope is still obscure. In order to learn the significance of OKT4-epitope, we performed immunological and functional studies on lymphocytes obtained from individuals with incomplete/complete OKT-4 epitope deficiency. Their lymphocytes did not show any abnormality in their susceptibility to HIV infection, the internalization of CD4 molecules by TPA-treatment, the capability of producing IL-2 in vitro or the expression of IL-2R (alpha/beta-chain) by PHA-stimulation. By flow cytometric analysis it was demonstrated that quantity of OKT4-epitopes in the incomplete deficiency was approximately one-half less than that of normal individuals. Coupled with this fact and DNA analysis previously reported, individuals with incomplete/complete OKT4-epitope deficiency were considered to be heterozygote and homozygote, respectively. These results led us to the conclusion that OKT4-epitope deficiency was inherited as an autosomal codominant trait. Individuals with complete OKT4-epitope deficiency were found in 7 cases out of 1486 random samples (0.47%), from which individuals with incomplete OKT4-epitope deficiency were estimated to account for 12.8%.