ANALYSIS OF MESSENGER-RNA FOR CLASS-I HLA ON HUMAN GAMETOGENIC CELLS

We have studied mRNA expression for Class I HLA (human leukocyte antig en) on male germ cells by amplification of gene fragments in PCR techn ique and by Northern hybridization. RNA was extracted from fractionate d gametogenic cells (isolated from testis) and reversely transcribed. Then, cDNA was amplified for specific HLA sequence (1151 bp) represent ing whole-length coding sequence (HLA, -A, -B, -C). The specificity of this product was confirmed in ''nested'' PCR of 400 bp gene fragment coding for alpha 2 domain, alpha 3 domain, and the transmembrane porti on of Class I HLA. The results indicate minimal expression of classica l Class I HLA on gametogenic cells. Northern hybridization with 669 bp cDNA fragment (spanning for alpha 3 domain, transmembrane, cytoplasmi c, and 3' untranslated region) resulted in a low intensity signal from gametogenic cell fractions and confirmed our findings obtained by PCR . The minimal expression of classical HLA antigens may create a neutra l cover for the male reproductive system, thereby preventing an immuno logical response during germ cell differentiation. (C) 1994 Wiley-Liss , Inc.