Analysis of the Epstein-Barr virus (EBV) latent membrane protein 1 (LMP-1)gene and promoter in Hodgkin's disease isolates: selection against EBV variants with mutations in the LMP-1 promoter ATF-1/CREB-1 binding site

Aims-To study the distribution of Epstein-Barr virus (EBV) variants contain ing mutations in the latent membrane protein 1 (LMP-1) oncogene and promote r in EBV associated Hodgkin's disease and infectious mononucleosis compared with previous findings in asymptomatic EBV carriers. Methods-Sequence analysis of the EBV LMP-1 promoter and gene in isolates fr om Danish patients with Hodgkin's disease (n = 61) and infectious mononucle osis (n = 10). Results-Viruses (previously designated group D) that contain two mutations in the activating transcription factor/cAMP response element (ATF/CRE) in t he LMP-1 promoter, which are known to decrease promoter activity greatly, w ere significantly less frequent in Hodgkin's disease than in both infectiou s mononucleosis (p = 0.0081) and asymptomatic EBV carriers (p = 0.0084). In some cases, the LMP-I gene contained mutations in a recently identified cy totoxic T cell (CTL) epitope, Most viral isolates contained mutations shown to increase nuclear factor kappa B (NF-kappa B) activation and had one of two newly identified C-terminal activation regions 3 (CTAR-3) deleted. The exon 1 Xho-I restriction site in the LMP-1 gene could be lost through a ran ge of different mutations. Conclusions-These findings indicate selection pressure against EBV strains with weak LMP-I promoter activity in Hodgkin's disease and thus provide fur ther strong circumstantial evidence for the pathogenic role of EBV land LMP -I) in this disease. Mutation of the CTL epitope suggests immune selection of EBV strains. Many EBV isolates contain functionally important mutations in the LMF-1 gene. Loss of the Xho-I restriction site should not be used as a marker of specific LMP-1 variants.