CD40 ligation downregulates EBNA-2 and LMP-1 expression in EBV-transformed lymphoblastoid cell lines.
Epstein-Barr virus (EBV) drives the proliferation of human B cells in vitro and during primary infection in vivo. The transformed immunoblasts express nuclear proteins EBNA1-6, transcribed from the Cp/Wp promoter, and the membrane proteins LMP-1, -2A and -2B (lymphoblastoid type of latency). EBV persists through life in resting memory B cells with a restricted type of latency in the absence of the Cp/Wp promoter activity. Since CD40 crosslinking can reportedly inhibit the growth of EBV-transformed lymphoblastoid cell lines (LCLs), we have examined the effect of CD40 ligation on the expression of EBNAs and LMP-1 and on Cp EBV promoter activity together with several phenotypic markers. CD40 crosslinking led to a partial downregulation of EBNA-2, EBNA3-6 and LMP-1 in LCLs, paralleled by downregulation of Cp promoter activity. It also induced upregulation of the germinal center marker CD77 on the LCL cells. Our findings suggest that the encounter of proliferating EBV-transformed immunoblasts with CD40L, as would occur when normal B cells generate memory cells in germinal centers, may switch the viral transcription program from the full lymphoblastoid to a more restricted latency program in a proportion of cells. This would permit virus persistence in the B-cell memory compartment.
Microbiology and Tumorbiology Center, Karolinska Institute, S-17177, Stockholm, Sweden.
Katja
K
Pokrovskaja
Barbro
B
Ehlin-Henriksson
Csaba
C
Kiss
Anita
A
Challa
John
J
Gordon
Peter
P
Gogolak
George
G
Klein
Laszlo
L
Szekely
D048868:Adaptor Proteins, Signal Transducing; D015703:Antigens, CD / Q000032:analysis; D001402:B-Lymphocytes / Q000276:immunology / Q000378:metabolism* / Q000821:virology*; D015153:Blotting, Western; D019013:CD40 Antigens / Q000378:metabolism*; D023201:CD40 Ligand / Q000378:metabolism / Q000494:pharmacology; D002352:Carrier Proteins / Q000235:genetics*; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D002472:Cell Transformation, Viral; D003598:Cytoskeletal Proteins; D019309:Epstein-Barr Virus Nuclear Antigens / Q000235:genetics*; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D060588:LIM Domain Proteins; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014764:Viral Proteins
D048868:Adaptor Proteins, Signal Transducing; D015703:Antigens, CD; D019013:CD40 Antigens; D002352:Carrier Proteins; D003598:Cytoskeletal Proteins; C402641:EBNA-2 protein, Human herpesvirus 4; D019309:Epstein-Barr Virus Nuclear Antigens; D047908:Intracellular Signaling Peptides and Proteins; D060588:LIM Domain Proteins; C484380:PDLIM7 protein, human; D012333:RNA, Messenger; D014764:Viral Proteins; D023201:CD40 Ligand