Bovine papilloma virus encoded E2 protein activates lymphokine genes through DNA elements, distinct from the consensus motif, in the long control region of its own genome.

Activation of T cells by antigen, lectin or a combination of phorbol ester (PMA) and calcium ionophore (A23187) leads to the induction of a set of lymphokine genes. Transfection of a human T cell leukemia cell line, Jurkat, or an African green monkey kidney cell line, CV1, with a cDNA encoding E2 protein, a trans-activator of bovine papilloma virus type 1, results in activation of interleukin 2 (IL-2), interleukin 3 (IL-3) and granulocyte/macrophage colony-stimulating factor (GM-CSF) genes in a transient transfection assay. 5' deletion and mutation analyses showed that the sequence between positions -60 and a TATA-like sequence is required for basic promotor function and that the sequence between positions -95 and -73 containing conserved lymphokine element 2 (CLE2) and a GC box (CLE2/GC box) mediates the positive response to E2 protein. The latter has been previously shown to respond to PMA/A23187 stimulation or to p40tax, a trans-activator encoded by human T cell leukemia virus type 1 (HTLV-I). The sequence located between -108 and -99 (CLE1) is inhibitory to E2 protein or PMA/A23187 stimulation. The combination of E2 protein and PMA/A23187 appears to eliminate an inhibitory effect of the upstream region. However, E2 protein, like p40tax, mediates a positive response through CLE1 alone linked to the basic promoter sequence. The level of activation of the long control region (LCR) by E2 protein is unaffected by the number of CLE2/GC box sequences.(ABSTRACT TRUNCATED AT 250 WORDS)     

Complete nucleotide sequence of the chromosomal gene for human IL-4 and its expression

We have isolated a chromosomal DNA segment of the human IL-4 gene based on homology with a human IL-4 cDNA sequence and determined its complete nucleotide sequence. The human IL-4 gene, which occurs as a single copy in the haploid genome, is mapped on chromosome 5. It is composed of four exons and three introns and is approximately 10 kilobase pairs in size. 5'-Flanking regions of human and mouse IL-4 genes share about 85% homology extending more than 500 base pairs upstream of a "TATA" like sequence. Several patches of sequences are found in the 5'-flanking region of the human IL-4 gene which are homologous to sequence in the 5'-flanking regions of the IL-2, IL-3, IL-5, and granulocyte-macrophage (GM)-CSF genes. The IL-4 gene is inducible after treatment of human T cell clone by phorbol-12-myristate-13-acetate (TPA) and calcium ionophore A23187. The 2.3-kb 5'-flanking region of the human IL-4 gene transiently transfected into Jurkat human T cell leukemia cells is activated efficiently in response to TPA and A23187 stimulation and, although less efficiently, by human T cell leukemia virus type I-encoded p40x or BPV-encoded E2 protein. Combination of TPA/A23187 and p40x or E2 protein further augmented the level of expression.     

Histamine acts directly on human T cells to inhibit interleukin-2 and interferon-gamma production

Histamine acts directly on human T cells to inhibit lymphokine production without the involvement of accessory cells. Histamine inhibits the production of interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) by purified human peripheral T cells activated in the presence of either intact monocytes or metabolically inactive fixed Raji and U698 cells as accessory cells. Purified T cells do not respond more than marginally to staphylococcal enterotoxin A (SEA) or phytohemagglutinin (PHA) in the absence of accessory cells. However, activation by the phorbol ester PMA in conjunction with either PHA or the calcium ionophore A23187 induces large amounts of IFN-gamma and IL-2. Histamine suppresses the lymphokine production in these pure T-cell cultures to a similar extent as in monocyte-containing cultures. Histamine is also shown to suppress DNA synthesis by purified T cells cultivated at a low cell density, eliminating any possible involvement of small numbers of contaminating accessory cells. In vitro preactivated T cells are shown to retain their capacity to respond to histamine when stimulated by PMA and A23187 or by mitogen in the presence of Raji cells. The conclusion that histamine acts directly on T cells and does not require accessory cells to induce suppression is further confirmed by the demonstration that IL-2 production by the human T-cell leukemia line Jurkat was significantly suppressed by histamine in a H-2 receptor-restricted manner.     

Human T-cell lymphotropic virus type-I tax gene induces interleukin-8 secretion by autocrine mechanism and has No effect on interleukin-16 in transfected Jurkat cells

Human T-cell lymphotropic virus I (HTLV-I) Tax has been shown to transactivate several cellular genes. In this study, we show that interleukin-8 (IL-8) is expressed and secreted in tax-transfected Jurkat cells that were further augmented by mitogen stimulation. Expression of high-affinity IL-8-R (Type A) mRNA in these cells suggests an autocrine role for this chemokine in HTLV-I-infected T-cells. However, interleukin-16 (IL-16) mRNA expression or protein secretion was not significantly modulated either constitutively or even upon mitogen stimulation in these tax-transfected cells.     

Activation of endogenous c-fos proto-oncogene expression by human T-cell leukemia virus type I-encoded p40tax protein in the human T-cell line, Jurkat.

We examined the ability of the trans-acting factor p40tax of human T-cell leukemia virus type I (HTLV-I), which is thought to be a crucial molecule in T-cell transformation by HTLV-I, to activate expression of a set of endogenous cellular genes related to T-cell proliferation. For this purpose we established a subclone (JPX-9) of Jurkat cells that was stably transfected with an expression plasmid containing the p40tax gene, whose expression is definitely dependent on heavy-metal ions. Expression of the interleukin-2 receptor alpha chain in JPX-9 cells was induced in response to the induction of p40tax expression, as has been demonstrated by others in transient transfection experiments with Jurkat cells. In addition, we found that significant enhancement of expression of the nuclear proto-oncogene c-fos was closely associated with expression of p40tax. Continous enhancement in the level of c-fos mRNA was observed in the presence of p40tax. In contrast, mRNA levels of other nuclear proto-oncogenes (c-myc, c-myb, and c-jun) were not appreciably effected by the expression of p40tax. These results suggest that (i) in addition to the interleukin-2-interleukin-2 receptor system, cellular genes such as c-fos, which regulate normal T-cell growth, are also activated directly or indirectly by p40tax and (ii) p40tax-induced modulation of gene expression plays a crucial role in T-cell transformation by HTLV-I.     

Human autologous rosette-forming cells. IV. Functional role in T-cell activation

Human autorosette-forming cells (auto-RFC), which represent a T4/leu 3a+ cell subset, were investigated for their functional role in T-cell activation. Peripheral blood lymphocytes from healthy subjects either remained unfractionated or were separated into recovered or depleted auto-RFC populations. The phytohemagglutinin P stimulation of these three cell suspensions induced normal levels of proliferation, whereas the pokeweed mitogen activation was significantly decreased in the auto-RFC-depleted population compared to the auto-RFC-recovered subset or unfractionated cells. All three cell suspensions produced IL-2 in response to PHA stimulation. However the levels of lymphokine released were significantly lower in the recovered auto-RFC fraction than in the depleted auto-RFC. After activation, using anti-Tac antibodies, the synthesis of IL-2 receptors was evidenced in all the cell fractions regardless of the presence or absence of auto-RFC. In addition, both auto-RFC absorbed IL-2 activity from a reference supernatant. Taken together, these data suggest that auto-RFC can be expanded by T-cell mitogens, and that once activated, they express IL-2 receptors, but represent a minor source of IL-2 production.     

Shock waves increase T-cell proliferation or IL-2 expression by activating p38 MAP kinase

Shock waves were elicited by transient pressure disturbances, which could be used to treat musculoskeletal disorders. In present studies, we investigated whether the low-density shock waves (LDSWs), which are able to damage plasma membrane without impairing the vimentin or other organelles, might augment T-