Frequent lack of translation of antigen presentation-associated molecules MHC class I, CD1a and B-2-microglobulin in Reed-Sternberg cells

Epstein-Barr virus (EBV) is present in Reed-Sternberg (RS) cells of a subst antial proportion of Hodgkin's lymphoma cases. Most EBV-positive cases are also MHC class I-positive, whereas the majority of EBV-negative cases lack detectable levels of MHC class I expression. Application of the SAGE techni que has led to the identification of tags corresponding to MHC class I and beta(2)-microglobulin genes in the EBV- and MHC class I-negative L428 Hodgk in's cell line. Further expression studies indicated that single RS cells t hat do not express HLA class I also lack beta(2)-microglobulins but frequen tly contain mRNA coding for these proteins. Another tag was identified corr esponding to CD1a, a thymocyte and Langerhans cell antigen structurally rel ated to the MHC class I genes. CD1a expression studies revealed mRNA in all cell lines and in several of the single cells, whereas immunostaining show ed a cytoplasmic signal in only 2 of the 4 cell lines and in none of the Ho dgkin's lymphoma tissue samples. In conclusion, RS cells frequently lack MH C class I, beta(2)-microglobulin and CD1a protein expression but contain mR NA coding for these proteins in some of the RS cells, suggesting a common m echanism affecting the translation of these antigen presentation-associated molecules. Int. J. Cancer 86:548-552, 2000. (C) 2000 Wiley-Liss, Inc.