TNF-beta (lymphotoxin) strongly upregulates TNF-alpha gene expression in human peripheral blood lymphocytes

L B Owen-Schaub1, M De Mars, E C Murphy

  • 1Department of Tumor Biology, University of Texas M.D. Anderson Cancer Center, Houston 77030.

Lymphokine Research
|January 11, 1990
PubMed

We investigated whether TNF-beta could induce or modulate TNF-alpha gene expression in human peripheral blood lymphocytes. For these experiments, lymphocytes were cultured in serum-free medium for 48 hours with human recombinant TNF-beta in the presence or absence of human recombinant IL-2. At the end of the culture period, total cellular RNA was isolated and probed for TNF-alpha mRNA using an S1 nuclease protection assay. TNF-beta alone was unable to induce lymphocyte TNF-alpha mRNA. However, when TNF-beta was used in combination with IL-2 an 8- to 12-fold increase in TNF-alpha mRNA compared to lymphocytes activated in IL-2 alone was observed. Secreted TNF-alpha was measured in the culture supernatants by TNF-alpha specific ELISA. Consistent with the results of mRNA analysis, TNF-beta alone did stimulate TNF-alpha secretion, but lymphocytes activated with TNF-beta/IL-2 demonstrated a 3- to 10-fold increase in secreted TNF-alpha over that induced by IL-2 alone. These experiments demonstrate that TNF-beta can participate in the upregulation of TNF-alpha gene expression in lymphocytes and suggest that cellular dysregulations involving autocrine TNF production may be exacerbated by this positive feedback pathway.

Related Concept Videos

NF-κB-dependent Signaling Pathway02:26

NF-κB-dependent Signaling Pathway

The transcription factor NF-κB was discovered in 1986 in the lab of Nobel laureate Professor David Baltimore, for its interaction with the immunoglobulin light chain enhancer in B-cells. After more than three decades of study, it is now evident that NF-κB regulates the expression of over 100 genes. Most of these genes play an essential role in the innate and adaptive immune responses as well as the inflammatory responses of animals.
NF-κB-dependent Signaling Mechanism
The heterodimer of NF-κB...
TGF - β Signaling Pathway01:16

TGF - β Signaling Pathway

The TGF-β signaling pathway regulates cell growth, differentiation, adhesion, motility, and development. TGF-β ligands that induce TGF-β signaling are synthesized in their latent form. Several proteases or cell surface receptors such as integrins act upon the latent form, releasing the active ligand. There are three types of mammalian TGF-βs: (TGF-β1, TGF-β2, and TGF-β3) that bind as homodimers or heterodimers to TGF-β receptors. The TGF-β receptors are of three kinds RI, RII, and RIII. The RI...
T Cell Types and Functions01:24

T Cell Types and Functions

When T cells with CD4 markers are activated, they give rise to two types of effector cells: helper T cells and regulatory T cells. Meanwhile, T cells with CD8 markers differentiate into effector cytotoxic T cells. The differentiation of CD4 T cells into helper T cell subsets, such as Th1, Th2, and Th17 cells, is dependent on the antigen type, antigen-presenting cell, and regulatory cytokines.
Th1 cells stimulate dendritic cells to express necessary co-stimulatory molecules on their surfaces for...