Bag-1 up-regulation in anti-CD4 mAb treated allo-activated T cells confers resistance to apoptosis.
The non-depleting anti-CD4 mAb RIB5/2 is a powerful inducer of tolerance to MHC-incompatible renal and heart allografts in rat recipients. In vitro the mAb blocks the proliferation and cytokine production of alloreactive T cells. To learn more about the mechanism of anti-CD4-mediated suppression, we applied differential display reverse transcription-PCR to identify differences at mRNA level between T cells stimulated by alloantigen in the presence or absence of anti-CD4 mAb. A sequence alignment of a 550-bp DNA fragment appearing only in anti-CD4 mAb-treated cells resulted in at least 95% homology to a mouse cDNA encoding for the anti-apoptotic protein Bag-1. Further investigation of Bag-1 expression during mixed lymphocyte reactions revealed a three- to fourfold up-regulation of Bag-1 mRNA expression in anti-CD4 mAb-treated allogeneic cultures which was confirmed at protein level. Bag-1 up-regulation was associated with an increase resistance to apoptosis of T cells from anti-CD4 mAb-treated cultures. Application of antisense oligonucleotides specific for Bag-1 reduced Bag-1 protein expression and restored susceptibility to apoptosis. In addition, up-regulation of Bag-1 mRNA could also be detected in graft-infiltrating T cells from anti-CD4 mAb-treated rats in vivo. Thus, the expression of Bag-1 in a subset of anti-CD4 mAb-treated alloreactive T cells conferred resistance against apoptosis, potentially contributing to the long-term survival of these cells.
Sawitzki
Birgit
B
Nuffield Department of Surgery, John Radcliffe Hospital, Oxford University, Oxford, GB. brigit.sawitzki@surgery.ox.ac.uk
Lehmann
Manfred
M
Vogt
Katrin
K
Risch
Kirsten
K
Brock
Josef
J
Kupiec-Weglinski
Jerzy W
JW
Volk
Hans-Dieter
HD
D019264:Adoptive Transfer; D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects* / Q000235:genetics; D015704:CD4 Antigens / Q000276:immunology / Q000502:physiology*; D002352:Carrier Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D004268:DNA-Binding Proteins; D053222:Fas Ligand Protein; D005786:Gene Expression Regulation / Q000187:drug effects*; D006084:Graft Rejection / Q000276:immunology*; D016027:Heart Transplantation / Q000276:immunology; D007108:Immune Tolerance / Q000276:immunology; D007519:Isoantigens / Q000276:immunology; D016030:Kidney Transplantation / Q000276:immunology; D008213:Lymphocyte Activation; D007959:Lymphocyte Culture Test, Mixed; D008562:Membrane Glycoproteins / Q000096:biosynthesis / Q000235:genetics; D051379:Mice; D016133:Polymerase Chain Reaction; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis / Q000235:genetics; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis; D011828:Radiation Chimera; D051381:Rats; D011919:Rats, Inbred Strains; D016415:Sequence Alignment; D013154:Spleen / Q000166:cytology / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000276:immunology* / Q000378:metabolism; D014157:Transcription Factors; D014184:Transplantation, Homologous; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein
D000911:Antibodies, Monoclonal; C091732:BCL2-associated athanogene 1 protein; C494812:Bcl2l1 protein, mouse; C494813:Bcl2l1 protein, rat; D015704:CD4 Antigens; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D053222:Fas Ligand Protein; C505658:Fasl protein, mouse; C505662:Faslg protein, rat; D007519:Isoantigens; D008562:Membrane Glycoproteins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D014157:Transcription Factors; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein