Blockage of nerve growth factor modulates T cell responses and inhibits allergic inflammation in a mouse model of asthma

Three lines of transgenic mice containing the human T-cell lymphotropic virus type I (HTLV-I) tax gene develop neurofibromas composed of perineural fibroblasts (S. H. Hinrichs, M. Nerenberg, R. K. Reynolds, G. Khoury, and G. Jay, Science 237:1340-1343, 1987; M. Nerenberg, S. H. Hinrichs, R. K. Reynolds, G. Khoury, and G. Jay, Science 237:1324-1327, 1987). Tumors and tumor cell lines derived from these mice produce neurite outgrowth from PC-12 cells and nerve growth factor (NGF), as determined by RNA (Northern) blot analysis and enzyme-linked immunosorbent assays. In vitro cotransfection studies demonstrate that Tax is able to trans activate the NGF promoter in NIH 3T3 fibroblast cells. The major cis-acting tax-responsive element in the NGF promoter (AGGGTGTGACGA) has 92% homology with a tax-responsive element contained within the 21-bp repeats of the HTLV-I long terminal repeat. The receptor for NGF is also expressed in the transgenic tumor cells, suggesting that Tax may activate an autocrine mechanism through the upregulation of NGF.

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Expression of nerve growth factor and nerve growth factor receptor tyrosine kinase Trk in activated CD4-positive T-cell clones

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.90.23.10984 ◽

1993 ◽

Vol 90 (23) ◽

pp. 10984-10988 ◽

Cited By ~ 196

Author(s):

P B Ehrhard ◽

P Erb ◽

U Graumann ◽

U Otten

Keyword(s):

T Cells ◽

Nerve Growth Factor ◽

T Cell ◽

Growth Factor ◽

Cd4 T Cells ◽

Cd4 T Cell ◽

T Cell Clones ◽

Nerve Growth ◽

Cell Clones ◽

Ngf Receptor

Recent evidence suggests that nerve growth factor (NGF), in addition to its neurotrophic functions, acts as an immunomodulator mediating "cross-talk" between neuronal and immune cells, including T lymphocytes. We have analyzed murine CD4+ T-cell clones for their ability to express transcripts encoding NGF, low-affinity NGF receptor, and trk protooncogene, the signal-transducing receptor subunit for NGF. We show that two CD4+ T-helper (Th) clones, Th0-type clone 8/37 and Th2-type clone D10.G4.1, express NGF and Trk mRNA after appropriate activation with mitogen or with antigen and antigen-presenting cells. NGF and trk induction occurred to a similar extent and over a similar time course in activated 8/37 T cells, raising the possibility that NGF and trk genes are under coordinate control. NGF and NGF receptor expression does not seem to be a universal property of all activated CD4+ T cells, since Th1-type clone 9/9 did not express any of the transcripts after either stimulation. The absence of low-affinity NGF receptor mRNA in resting and activated T cells implies that the low-affinity NGF receptor is not involved in NGF signal transduction in CD4+ T cells. Our finding that activated CD4+ T-cell clones not only express Trk but also synthesize and release biologically active NGF implicates NGF as an autocrine and/or paracrine factor in the development and regulation of immune responses.

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