Linkage of superantigen-like stimulation of syngeneic T cells in a mouse model of follicular center B cell lymphoma to transcription of endogenous mammary tumor virus.
The MHC class II I-A(s) positive B cell lymphomas reticulum cell sarcoma (RCS) that arise in > 90% of SJL mice by the age of 12 months have superantigen-like stimulating properties. In the present study, therefore, RCS cell lines were examined for abnormal expression of endogenous mouse mammary tumor virus (MMTV) proviruses. Extraordinarily high expression of a 1.8 kb mRNA hybridizing with the long terminal repeat (LTR) of MMTV was found in both primary lymphomas and in vitro RCS lines, but not in an SJL B cell lymphoma, NJ101, that does not stimulate syngeneic T cells, or in LPS activated SJL B cells. A cDNA was cloned from cRCS-2 and sequenced. A 31mer oligonucleotide probe, prepared based on the unique C-terminal sequence of this RCS-Mtv LTR, detected the 1.8 kb mRNA in all RCS lymphomas, while a similar probe for the C-terminal sequence of Mtv-8 LTR hybridized with the larger mRNA present in normal B cells and in NJ101. Preincubation with 19mer antisense S-oligonucleotides, prepared based on the sequences of the first two potential translation initiation sites common to both Mtv-8 and the RCS-Mtv LTR, significantly reduced the ability of RCS cells to stimulate syngeneic T cells. Moreover, transfection of NJ101 cells with the cloned RCS-MMTV cDNA conferred V beta 16 T cell stimulating properties on to these cells. It is concluded that expression of the product of this MMTV-LTR mRNA provides RCS with the strong T cell stimulating properties that it needs for its growth. These results thus identify a novel oncogenic property of MMTV-LTR.
Tsiagbe
V K
VK
Department of Pathology, Kaplan Comprehensive Cancer Center, New York University School of Medicine, NY 10016.
Yoshimoto
T
T
Asakawa
J
J
Cho
S Y
SY
Meruelo
D
D
Thorbecke
G J
GJ
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D004247:DNA; D004195:Disease Models, Animal; D005814:Genes, Viral; D008213:Lymphocyte Activation; D016393:Lymphoma, B-Cell / Q000235:genetics / Q000276:immunology*; D008324:Mammary Tumor Virus, Mouse / Q000235:genetics*; D051379:Mice; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000378:metabolism; D012091:Repetitive Sequences, Nucleic Acid; D013601:T-Lymphocytes / Q000276:immunology*; D014158:Transcription, Genetic
D012333:RNA, Messenger; D004247:DNA