Date: Sunday, May 3, 2015
Session Time: 5:30pm-6:30pm
Presentation Time: 5:30pm-6:30pm
Location: Exhibit Hall E
Introduction:-The distribution of Epstein Barr Virus (EBV)-associated pathologies varies worldwide. It is associated with the majority of cases of post-transplant lymphoproliferative disorder (PTLD). The EBNA-1 gene encodes a fundamental protein as it helps maintain the EBV episome and is expressed in all EBV-associated malignancies. It is unclear whether variation within EBNA-1 accounts for these different pathologies, or whether variation in the EBNA-1 sequence is simply due to varying geographical distribution.
Methods: We sequenced the EBNA-1 gene of samples from transplant patients and patients with infectious mononucleosis (IM). Sequencing was done by Sanger methodology and the sequences were aligned with reference strains and compared with publically available databases.
Results: There were 20 samples; transplant = 11, IM = 9. Male to female ratio 1:1.16, age range 1-17 years. Of the transplant patients, 4 had PTLD. Phylogenetic trees showed there was great genetic diversity between strains when compared to publicly available sequences and no particular disease-related clustering. Within the carboxy terminal of EBNA-1 we found eighteen sites associated with amino acid substitutions;(residues 410, 429, 439, 471, 476, 487, 492, 499, 500, 502, 524, 525, 563, 574, 585, 588, 594, 595). Looking at the amino acid at position 487, transplant strains were more likely the P-Thr subtype, and less likely the P-Ala subtype, compared to IM strains; (71% of non-PTLD transplant strains were of the P-Thr subtype, compared to 75% of PTLD strains and 67% of IM strains, while 14% of non-PTLD strains were P-Ala, compared to 25% of PTLD strains and 33% of IM strains). Interestingly,14% of non-PTLD transplant strains were of the V-Leu subtype. The percentage of amino acid substitutions was higher in the transplant patients, (52% in non-PTLD samples, 45% in PTLD samples, compared with 40% in IM samples).
Conclusion: In conclusion, we generated 20 new EBNA-1 sequences from strains isolated in Toronto and showed that there is genetic diversity in EBNA-1 sequences within one city. Our initial findings suggest that the type and frequency of amino acid substitutions may vary between transplant patients compared with patients with infectious mononucleosis. Further research will define the significance of these observations.
To cite this abstract in AMA style:Sullivan K, Isabel S, Maria E, Tara P, Simon Y, Nasser K, Vicky N, Upton A. Genetic Diversity Epstein-Barr Virus Latent Gene EBNA-1 Among Transplant Patients and Patients With Infectious Mononucleosis [abstract]. Am J Transplant. 2015; 15 (suppl 3). https://atcmeetingabstracts.com/abstract/genetic-diversity-epstein-barr-virus-latent-gene-ebna-1-among-transplant-patients-and-patients-with-infectious-mononucleosis/. Accessed November 29, 2020.
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