Expression of epstein-barr virus encoded nuclear antigen 1 in benign and malignant tissues harbouring EBV.
OBJECTIVE
To determine levels of expression of Epstein-Barr virus (EBV) nuclear antigen 1 (EBNA1) in benign and malignant tissues harbouring EBV in relation to EBNA1 promoter usage.


METHODS
Expression of EBNA1 was investigated by means of immunohistochemistry using a mixture of two EBNA1 specific monoclonal antibodies, 1H4-1 and 2B4-1. The presence of EBV was detected by EBER1/2 RNA in situ hybridisation. Detection of promoter specific EBNA1 transcripts was by RT-PCR analysis.


RESULTS
EBNA1 positive cells were detected in all 20 EBV associated B cell lymphomas, 18 of which had arisen in immunocompromised patients; in eight of nine EBV associated T cell lymphomas; in 11 of 27 EBV positive cases of Hodgkin's disease; and in reactive lymphoid tissue harbouring EBV, including four cases of infectious mononucleosis. A diffuse EBNA1 staining pattern was observed in most of the EBV associated B cell lymphomas and was comparable with the EBER1/2 staining pattern. In the T cell lymphomas the number of EBNA1 positive cells was usually considerably less than the number of EBER1/2 positive ones. RT-PCR analysis revealed that in tumours with restricted EBNA1 expression-that is, T cell lymphomas and Hodgkin's disease lesions, EBNA1 transcripts were usually generated only by the F/Q promoter, whereas in B cell lymphomas EBNA1 transcripts were usually generated by both the C/W and F/Q promoters.


CONCLUSIONS
EBNA1 is expressed in all types of tissue harbouring EBV, but the level of expression varies greatly. This may be the result of differential promoter usage.
Oudejans
J J
JJ
Department of Pathology, Free University Hospital, Amsterdam, The Netherlands.
Dukers
D F
DF
Jiwa
N M
NM
van den Brule
A J
AJ
Grässer
F A
FA
de Bruin
P C
PC
Horstman
A
A
Vos
W
W
van Gorp
J
J
Middeldorp
J M
JM
Meijer
C J
CJ
D000956:Antigens, Viral / Q000378:metabolism*; D004854:Herpesvirus 4, Human / Q000235:genetics / Q000276:immunology*; D006689:Hodgkin Disease / Q000821:virology; D006801:Humans; D016867:Immunocompromised Host; D007150:Immunohistochemistry; D007244:Infectious Mononucleosis / Q000821:virology*; D008223:Lymphoma / Q000276:immunology / Q000821:virology*; D016393:Lymphoma, B-Cell / Q000276:immunology / Q000821:virology; D016399:Lymphoma, T-Cell / Q000821:virology; D011401:Promoter Regions, Genetic / Q000502:physiology; D014158:Transcription, Genetic
D000956:Antigens, Viral