Frequent lack of translation of antigen presentation-associated molecules MHC class I, CD1a and B2-microglobulin in Reed-Sternberg cells

Abstract

Epstein-Barr virus (EBV) is present in Reed-Sternberg (RS) cells of a substantial 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 1 expression. Application of the SAGE technique has led to the identification of tags corresponding to MHC class I and β2-microglobulin genes in the EBV- and MHC class I-negative L428 Hodgkin's cell line. Further expression studies indicated that single RS cells that do not express HLA class I also lack β2-microglobulins but frequently contain mRNA coding for these proteins. Another tag was identified corresponding to CDla, a thymocyte and Langerhans cell antigen structurally related to the MHC class genes. CD la expression studies revealed mRNA in all cell lines and in several of the single cells, whereas immunostaining showed a cytoplasmic signal in only 2 of the 4 cell lines and in none of the Hodgkin's lymphoma tissue samples. In conclusion, RS cells frequently lack MHC class I, β2-microglobulin and CD la protein expression but contain mRNA coding for these proteins in some of the RS cells, suggesting a common mechanism affecting the translation of these antigen presentation-associated molecules. (C) 2000 Wiley-Liss, Inc.