The induction of T cell proliferation and differentiation into mature effector cells is dependent on two principal exogenous signals that are provided by the antigen or mitogen and IL2. The enzyme protein kinase C (PKC) has a major role in the antigen-receptor signalling pathway in T cells, but appears not to be involved in signalling via the IL2-receptor (IL2-R). Since both pathways trigger a series of sequentially coordinated transcriptional events in which numerous genes are activated, we tested whether a T cell mitogen acting via the TCR/CD3 complex, and IL2, affect the expression of the conventional, Ca(2+)-dependent, PKC genes (alpha, beta and gamma) in T cells. Stimulation of human peripheral blood lymphocytes or an enriched population of human T cells with phytohemagglutinin resulted in augmented mRNA levels of PKC alpha and PKC beta, but not PKC gamma-gene. The response peaked at 24-48 hr when a 3-5-fold increase was observed. Stimulation of IL2-R alpha-expressing T cells with human recombinant IL2 induced cell proliferation and transcription of the IL2-R alpha gene (greater than 100-fold), but did not change mRNA levels of PKC alpha or PKC beta genes. The results suggest that stimulation of human T cells with mitogens acting via the TCR/CD3 complex, that involve activation of PKC, is accompanied also by a late activation of selected PKC genes. By contrast, agonists such as IL2, that operate via a different signalling pathway, do not modify the expression of any of the known conventional PKC genes.

Gene Expression↗

PubMedDate not supplied

Crohn's ileocolitis, cutaneous gangrene and cryoglobulinema.

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Adult↗

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Treatment of fractures of the middle third of the root.

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Humans↗

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The biological effects of allogeneic effect factor (AEF) on T lymphocytes. III.--Interferon does not contribute to the biological activities displayed by AEF on both T and B lymphocytes.

The studies reported here were designed to evaluate the potential contribution of interferon (IF) to the biological activities mediated by allogeneic effect factor (AEF), a soluble product of allogeneic cell interactions, on responses of T and B lymphocytes. AEF supernatants were found to contain varying levels of IF, predominantly of type II (immune). AEF preparations which were practically free of--or very low in--IF activity were obtained by bovine serum albumin-Sepharose chromatography of AEF, or by using strain combinations involving K-only or I-only differences within the H-2 complex for the production of AEF. Such preparations retained their biological activities in three in vitro assays characteristic of AEF: (a) induction of primary self-H-2-reactive cytotoxic T-lymphocyte responses, (b) mitogenicity for normal T cells, and (c) induction of plaque-forming cell antibody responses to a T-dependent antigen in T-cell-depleted spleen cultures. These results demonstrate that IF does not play any significant role in the biological activities medicated by AEF.

Animals↗

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Use of terminal deoxynucleotidyl transferase in the diagnosis of leukemia.

Terminal deoxynucleotidyl transferase (TdT) was determined by immunofluorescence in 30 patients with leukemia. In acute lymphocytic leukemia the proportion of cells positive for TdT was 19 to 77 percent during relapse (12 cases) and less than one percent during remission (three cases). In seven cases of myeloproliferative disease and two cases of lymphoma, the TdT was less than one percent. In one case of generalized lymphoblastic lymphoma and five cases of chronic myelocytic leukemia with "lymphoblastic" crisis, the cells positive for TdT were moderately increased. The presence of TdT in blast cells appears to have diagnostic, therapeutic, and prognostic significance.

Adolescent↗

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The use of leukocyte acid phosphatase in the diagnosis of malignant disease. Case report and review of literature.

Tartrate resistant acid phosphatase (TRAP) has been demonstrated during relapse in the cells in the cerebral spinal fluid (CSF) in a patient with the clinical features of acute T cell lymphocytic leukemia which suggests this isozyme may be a marker for malignant transformation of some types of lymphocytes. The presence of TRAP may be helpful in establishing the diagnosis of a lymphocytic malignancy since normal lymphocytes appear to have tartrate sensitive acid phosphatase. The presence of TRAP can no longer be considered specific for hairy cell leukemia, since children with acute lymphocytic leukemia are being found with this isozyme in their malignant blasts. The presence of TRAP does not appear to be specific for T or B cell lines of malignant lymphocytes since it has been described in cells with either type of cell markers. The presence of TRAP seems most useful in differentiating lymphocytic malignancies from monocytic and histiocytic malignancies and from benign lymphocytoses when the cells of the peripheral blood and marrow may have similar morphologic features with routine staining.

Acid Phosphatase↗