Genetic variability and mutation of Epstein‒Barr virus (EBV)-encoded LMP-1 and BHRF-1 genes in EBV-infected patients: identification of precise targets for development of personalized EBV vaccines.

The critical Epstein‒Barr virus (EBV)-encoded latent membrane protein 1 (LMP-1) and BamHI fragment H rightward open reading frame 1 (BHRF-1) genes affect EBV-mediated malignant transformation and virus replication during EBV infection. Therefore, these two genes are considered ideal targets for EBV vaccine development. However, gene mutations in LMP-1 and BHRF-1 in different cohorts may affect the biological functions of EBV, which would seriously hinder development of personalized vaccines for EBV. In the present study, by performing nested polymerase chain reaction (nested PCR) and DNA sequence techniques, we analyzed the nucleotide variability and phylogeny of LMP-1 containing a 30 bp deletion region (del-LMP-1) and BHRF-1 in EBV-infected patients (N = 382) and healthy persons receiving physical examination (N = 98; defined as the control group) in Yunnan Province, China. Three BHRF-1 subtypes were identified in this study: 79V88V, 79L88L, and 79V88L, with mutation frequencies of 58.59%, 24.24%, and 17.17%, respectively. Compared with the control group, the distribution of BHRF-1 subtypes of the three groups showed no significant difference, suggesting that BHRF-1 is highly conserved in EBV-related samples. In addition, a short fragment of del-LMP-1 was found in 133 cases, and the nucleotide variation rate was 87.50% (133/152). For del-LMP-1, a significant distribution in three groups was detected, as characterized by a high mutation rate. In conclusion, our study illustrates gene variability and mutations of EBV-encoded del-LMP-1 and BHRF-1 in clinical samples. Highly mutated LMP-1 might be associated with various types of EBV-related diseases, indicating that BHRF-1 combined with LMP-1 may be used as an ideal target for development of EBV personalized vaccines.