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Epstein-Barr virus infection in chronically inflamed periapical granulomas.

Makino K, Takeichi O, Hatori K, Imai K, Ochiai K, Ogiso B - PLoS ONE (2015)

Bottom Line: In contrast, EBV DNA was not detected in healthy gingival tissues (n = 10); the difference was statistically significant according to the Mann-Whitney U test (p = 0.0001).Paraffin sections were also analyzed by in situ hybridization to detect EBV-encoded small RNA (EBER)-expressing cells.In addition, immunohistochemical analysis for latent membrane protein 1 (LMP-1) of EBV using serial tissue sections showed that LMP-1-expressing cells were localized to the same areas as EBER-expressing cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Endodontics, Nihon University School of Dentistry, Chiyoda-ku, Tokyo, Japan.

ABSTRACT
Periapical granulomas are lesions around the apex of a tooth caused by a polymicrobial infection. Treatment with antibacterial agents is normally performed to eliminate bacteria from root canals; however, loss of the supporting alveolar bone is typically observed, and tooth extraction is often selected if root canal treatment does not work well. Therefore, bacteria and other microorganisms could be involved in this disease. To understand the pathogenesis of periapical granulomas more precisely, we focused on the association with Epstein-Barr virus (EBV) using surgically removed periapical granulomas (n = 32). EBV DNA was detected in 25 of 32 periapical granulomas (78.1%) by real-time PCR, and the median number of EBV DNA copies was approximately 8,688.01/μg total DNA. In contrast, EBV DNA was not detected in healthy gingival tissues (n = 10); the difference was statistically significant according to the Mann-Whitney U test (p = 0.0001). Paraffin sections were also analyzed by in situ hybridization to detect EBV-encoded small RNA (EBER)-expressing cells. EBER was detected in the cytoplasm and nuclei of B cells and plasma cells in six of nine periapical granulomas, but not in healthy gingival tissues. In addition, immunohistochemical analysis for latent membrane protein 1 (LMP-1) of EBV using serial tissue sections showed that LMP-1-expressing cells were localized to the same areas as EBER-expressing cells. These data suggest that B cells and plasma cells in inflamed granulomas are a major source of EBV infection, and that EBV could play a pivotal role in controlling immune cell responses in periapical granulomas.

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LMP-1 immunohistochemistry using serial sections of periapical granulomas.Framed boxes in left panels (A, C, E) were magnified to right panels (B, D, F, respectively). (A, B) LMP-1 immunohistochemistry showed positive staining in B cells (arrows) and plasma cells (arrow heads). (C, D) EBER-expressing cells were present at the same area of LMP-1-expressing cells. (E, F) A negative control using normal mouse IgG antibody did not exhibit LMP-1 expression. Scale bar = 50μm.
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pone.0121548.g005: LMP-1 immunohistochemistry using serial sections of periapical granulomas.Framed boxes in left panels (A, C, E) were magnified to right panels (B, D, F, respectively). (A, B) LMP-1 immunohistochemistry showed positive staining in B cells (arrows) and plasma cells (arrow heads). (C, D) EBER-expressing cells were present at the same area of LMP-1-expressing cells. (E, F) A negative control using normal mouse IgG antibody did not exhibit LMP-1 expression. Scale bar = 50μm.

Mentions: Immunohistochemistry for LMP-1 was also performed in periapical granulomas and healthy gingival tissues. All of the EBER-positive periapical granulomas that were confirmed by ISH showed positive staining for LMP-1 (Fig 5A and 5B). LMP-1 was expressed by B lymphocytes and plasma cells. In addition, EBER-expressing cells were localized to the same areas as LMP-1-expressing cells, based on serial tissue sections (Fig 5C and 5D). A negative control using normal mouse IgG antibody did not exhibit LMP-1 expression (Fig 5E and 5F). Healthy gingival tissues showed negative expression of LMP-1 (data not shown).


Epstein-Barr virus infection in chronically inflamed periapical granulomas.

Makino K, Takeichi O, Hatori K, Imai K, Ochiai K, Ogiso B - PLoS ONE (2015)

LMP-1 immunohistochemistry using serial sections of periapical granulomas.Framed boxes in left panels (A, C, E) were magnified to right panels (B, D, F, respectively). (A, B) LMP-1 immunohistochemistry showed positive staining in B cells (arrows) and plasma cells (arrow heads). (C, D) EBER-expressing cells were present at the same area of LMP-1-expressing cells. (E, F) A negative control using normal mouse IgG antibody did not exhibit LMP-1 expression. Scale bar = 50μm.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4401687&req=5

pone.0121548.g005: LMP-1 immunohistochemistry using serial sections of periapical granulomas.Framed boxes in left panels (A, C, E) were magnified to right panels (B, D, F, respectively). (A, B) LMP-1 immunohistochemistry showed positive staining in B cells (arrows) and plasma cells (arrow heads). (C, D) EBER-expressing cells were present at the same area of LMP-1-expressing cells. (E, F) A negative control using normal mouse IgG antibody did not exhibit LMP-1 expression. Scale bar = 50μm.
Mentions: Immunohistochemistry for LMP-1 was also performed in periapical granulomas and healthy gingival tissues. All of the EBER-positive periapical granulomas that were confirmed by ISH showed positive staining for LMP-1 (Fig 5A and 5B). LMP-1 was expressed by B lymphocytes and plasma cells. In addition, EBER-expressing cells were localized to the same areas as LMP-1-expressing cells, based on serial tissue sections (Fig 5C and 5D). A negative control using normal mouse IgG antibody did not exhibit LMP-1 expression (Fig 5E and 5F). Healthy gingival tissues showed negative expression of LMP-1 (data not shown).

Bottom Line: In contrast, EBV DNA was not detected in healthy gingival tissues (n = 10); the difference was statistically significant according to the Mann-Whitney U test (p = 0.0001).Paraffin sections were also analyzed by in situ hybridization to detect EBV-encoded small RNA (EBER)-expressing cells.In addition, immunohistochemical analysis for latent membrane protein 1 (LMP-1) of EBV using serial tissue sections showed that LMP-1-expressing cells were localized to the same areas as EBER-expressing cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Endodontics, Nihon University School of Dentistry, Chiyoda-ku, Tokyo, Japan.

ABSTRACT
Periapical granulomas are lesions around the apex of a tooth caused by a polymicrobial infection. Treatment with antibacterial agents is normally performed to eliminate bacteria from root canals; however, loss of the supporting alveolar bone is typically observed, and tooth extraction is often selected if root canal treatment does not work well. Therefore, bacteria and other microorganisms could be involved in this disease. To understand the pathogenesis of periapical granulomas more precisely, we focused on the association with Epstein-Barr virus (EBV) using surgically removed periapical granulomas (n = 32). EBV DNA was detected in 25 of 32 periapical granulomas (78.1%) by real-time PCR, and the median number of EBV DNA copies was approximately 8,688.01/μg total DNA. In contrast, EBV DNA was not detected in healthy gingival tissues (n = 10); the difference was statistically significant according to the Mann-Whitney U test (p = 0.0001). Paraffin sections were also analyzed by in situ hybridization to detect EBV-encoded small RNA (EBER)-expressing cells. EBER was detected in the cytoplasm and nuclei of B cells and plasma cells in six of nine periapical granulomas, but not in healthy gingival tissues. In addition, immunohistochemical analysis for latent membrane protein 1 (LMP-1) of EBV using serial tissue sections showed that LMP-1-expressing cells were localized to the same areas as EBER-expressing cells. These data suggest that B cells and plasma cells in inflamed granulomas are a major source of EBV infection, and that EBV could play a pivotal role in controlling immune cell responses in periapical granulomas.

Show MeSH
Related in: MedlinePlus