Epstein-barr virus diversity in immunocompetent healthy persons: reassessment of the distribution of genetic variants.

Epstein-Barr virus (EBV) has many strains; however, it remains unclear whether a causal relationship exists between different regions and viral genetic variants in healthy persons. This study was designed to examine the relationship between EBV strains in tonsils and adenoids and peripheral blood lymphocytes of the same individuals using different measurements of EBV strain polymorphism. This study examined whether EBV contains two or three copies of a tandem repeat sequence in the first intron of the BZLF-1 gene. The genotype of the virus from P3HR-1, designated Z*, yielded a 415-bp product, and this was distinguished from the smaller, 386-bp product obtained with the B95-8 virus, designated the Z genotype. Simultaneous sequence infections with Z and Z* genotypes were also detected in one of the tonsils examined, suggesting that more than one strain or variant of EBV genotype may be present in a specimen from the same subject. Co-infection with Z and Z* was recognized in two subjects, so variation of the EBV gene may be seen in at least two different strains of EBV. It was seen that Z and Z* strain-infected cells are constantly in flux through lymph nodes and/or the blood stream in healthy persons; therefore, these results indicated that EBV genome variants probably show no specific tissue distribution.