VavP-Bcl2 transgenic mice develop follicular lymphoma preceded by germinal center hyperplasia.
In human follicular lymphoma the t(14; 18) chromosome translocation activates the antiapoptotic oncogene Bcl2 by linking it to the immunoglobulin heavy chain (IGH) locus. Transgenic mice expressing Bcl2 controlled by an Igh enhancer (E mu) do not develop follicular lymphoma, although they do have an increased incidence of other B-lymphoid neoplasms. We have now analyzed tumorigenesis in mice bearing a Bcl2 transgene controlled by Vav gene regulatory sequences (VavP), which confer expression in multiple hematopoietic lineages. Unlike E mu-Bcl2 mice, many VavP-Bcl2 mice older than 10 months developed follicular lymphoma. Young VavP-Bcl2 mice had an overabundance of enlarged germinal centers and greatly elevated numbers of cycling B cells that had undergone IgH class switching and V-gene hypermutation. The peripheral T-cell compartment was larger in the VavP-Bcl2 mice than in E mu-Bcl2 strains and, notably, CD4 T cells were 5-fold increased over normal. The germinal center hyperplasia required CD4 T cells, because it could be abolished by anti-CD4 antibody in vivo. VavP-Bcl2 mice also had a propensity to develop kidney disease of the autoimmune type. We suggest that the increased survival capacity of B and T cells fosters prolonged germinal center reactions, and that autoreactivity and hypermutation conspire to generate follicular lymphoma.
Egle
Alexander
A
Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia.
Harris
Alan W
AW
Bath
Mary L
ML
O'Reilly
Lorraine
L
Cory
Suzanne
S
D000818:Animals; D001402:B-Lymphocytes / Q000502:physiology; D001483:Base Sequence; D015496:CD4-Positive T-Lymphocytes / Q000502:physiology; D004195:Disease Models, Animal; D015972:Gene Expression Regulation, Neoplastic; D018858:Germinal Center / Q000473:pathology; D006965:Hyperplasia; D008224:Lymphoma, Follicular / Q000473:pathology / Q000503:physiopathology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D015513:Oncogene Proteins / Q000235:genetics*; D010641:Phenotype; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics*; D051567:Proto-Oncogene Proteins c-vav; D027041:Somatic Hypermutation, Immunoglobulin; D019076:Transgenes / Q000502:physiology
D015513:Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D051567:Proto-Oncogene Proteins c-vav; C496619:Vav1 protein, mouse