Cloning a new allele form of bovine TNF-alpha

Although little is known on the function of gammadelta T lymphocytes, there is increasing evidence that gammadelta T lymphocytes are early responders and modulators of immune responses against pathogens and cytokines such as IL-2, IL-7, IL-15 and TNF-alpha. To study the role TNF-alpha on gammadelta T lymphocytes, we cloned bovine TNF-alpha. Sequence analysis revealed that a new allele form of bovine TNF-alpha was cloned which has 3 additional nucleotide sequences as well as 3 nucleotide substitutions compared with previously reported bovine TNF-alpha. Further studies are needed to document the functional significance of a new allele form of TNF-alpha in cattle.

Regulation of gamma T-cell antigen receptor expression by intracellular calcium in acute lymphoblastic leukemia cell line DND41

The calcium inophore, ionomycin, promotes an increase of intracellular calcium and regulates mRNA expression of gamma/delta-TcR gene in human T lymphocytes. The mechanism of this regulation is not yet clear. Thus, the regulation by intracellular calcium requires elucidation. We studied the gamma-TcR gene expression in acute lymphoblastic leukemia cell line DND41 (CD4-CD8-) by Northern blot and flow cytometric analysis. The mRNA levels of gamma-TcR increased by ionomycin, anti-CD3, and with TPA. TPA had an antagonistic effect to both ionomycin and anti-CD3. Also, TPA inhibitis the increased intracellular calcium promoted by ionomycin but not the increase promoted by antiCD3 and ionomycin. Our results suggest that intracellular calcium induces mRNA and protein expression of gamma-TcR chain. This effect is antagonized by protein kinase C-activation. Thus, we conclude that the target cells of the differential regulation on gamma-TcR mRNA expression by intracellular calcium modulators are the CD4-CD8- cells, and this is due to cytosolic calcium mobilization