SP600125, an anthrapyrazolone inhibitor of Jun N-terminal kinase

Jun N-terminal kinase (JNK) is a stress-activated protein kinase that can be induced by inflammatory cytokines, bacterial endotoxin, osmotic shock, UV radiation, and hypoxia. We report the identification of an anthrapyrazolone series with significant inhibition of JNK1, -2, and -3 (K(i) = 0.19 microM). SP600125 is a reversible ATP-competitive inhibitor with >20-fold selectivity vs. a range of kinases and enzymes tested. In cells, SP600125 dose dependently inhibited the phosphorylation of c-Jun, the expression of inflammatory genes COX-2, IL-2, IFN-gamma, TNF-alpha, and prevented the activation and differentiation of primary human CD4 cell cultures. In animal studies, SP600125 blocked (bacterial) lipopolysaccharide-induced expression of tumor necrosis factor-alpha and inhibited anti-CD3-induced apoptosis of CD4(+) CD8(+) thymocytes. Our study supports targeting JNK as an important strategy in inflammatory disease, apoptotic cell death, and cancer.

Development of a clinically applicable high-speed flow cytometer for the isolation of transplantable human hematopoietic stem cells

A high-speed cell sorter capable of a throughput speed 4-5-fold greater than commercially available systems was developed and evaluated as a processing tool for isolating purified hematopoietic stem cell grafts. The clinical high-speed sorter (CHSS) serves as a single-pass, multiparameter processing tool that provides the means to isolate a highly purified population of cells from starting cell populations with extremely low frequencies. The sorter incorporates environmental barriers to create a sterile environment for cell processing. Monoclonal antibodies and reagents produced under good manufacturing practices (GMP) are used to isolate hematopoietic stem cells by means of the CHSS. Using this technology, the CD34+Thy-1+Lin- hematopoietic stem cell population has been isolated from normal adult bone marrow and mobilized peripheral blood. The sorted cells have been shown to be sterile and viable and to retain hematopoietic function.

Reconstitution of Mycobacterium leprae immunity in severe combined immunodeficient mice using a T-cell line

To test whether Mycobacterium leprae-immune T cells can confer protection against infection with leprosy bacilli, severe combined immunodeficient (SCID) mice were reconstituted with a BALB/c-derived, M. leprae-responsive, T-cell line. Flow cytometric analysis of spleen and peripheral blood cells confirmed reconstitution with T cells. In vitro lymphokine production and the proliferation of spleen cells from the reconstituted animals established that the donor cells had maintained their functional activity for the duration of the study (275 days). The transfer of immune T cells 24 hr before foot pad infection with leprosy bacilli resulted in a profound reduction in M. leprae multiplication, as compared to the nonreconstituted SCID mice. The yield of acid-fast bacilli in the foot pads of SCID mice reconstituted with the M. leprae-immune T cells also was significantly lower than that found in naive BALB/c mice, and at levels previously found only in BALB/c mice that had been immunized effectively. These experiments demonstrate that M. leprae-immune T cells home effectively and control M. leprae infection in SCID mice.

Leu-8/CD7 antigen expression by CD3+ T cells: comparative analysis of skin and blood in mycosis fungoides/Sézary syndrome relative to normal blood values

Deficiencies of Leu-8 and CD7 antigens are exhibited by CD3+ T cells in the skin lesions of most patients with mycosis fungoides/Sézary syndrome. To determine whether these antigenic abnormalities are limited to involved skin, we studied Leu-8/CD7 expression in 21 skin lesions of mycosis fungoides/Sézary syndrome obtained from 16 patients and compared them with their peripheral blood leukocytes obtained concurrently. There was no correlation between Leu-8/CD7 values in skin lesions versus blood. Blood values were relatively uniform; most patients had 50% or greater of CD3+, Leu-8+ T cells and CD3+, CD7+ T cells. In contrast, skin values were highly heterogeneous; most patients lacked expression of Leu-8 or CD7 by the majority of lesional CD3+ T cells. Furthermore, Leu-8/CD7 antigen deficiency was present in lesional skin in one patient with mycosis fungoides but not in her concurrently sampled pityriasis lichenoides chronica or blood. These findings suggest that Leu-8/CD7 antigen deficiencies in skin lesions of mycosis fungoides/Sézary syndrome do not represent generalized antigenic abnormalities of CD3+ T cells in other body compartments and that within the skin, these deficiencies are disease specific within individual patients with more than one dermatosis. Comparative peripheral blood immunophenotyping of the patients with mycosis fungoides/Sézary syndrome and of the control subjects indicated that the control ranges of CD3+/Leu-8+ and CD3+/CD7+ T cells (33% or greater) extend lower than reported previously (60% or greater) and suggested that leukemic involvement in patients with mycosis fungoides/Sézary syndrome may correlate with percentages of CD3+, Leu8+ and/or CD3+, CD7+ T cells that fall below the revised control range.

Discrimination of viable and non-viable cells using propidium iodide in two color immunofluorescence

The relative ease with which a flow cytometer can perform simultaneous two color immunofluorescence to examine subpopulations of lymphoid cells has been well documented. Thus, flow cytometers equipped with only a single argon laser can be used to delineate various cell types by exciting both fluorescein- and phycoerythrin-conjugated antibodies to cell surface antigens. One problem that remains, however, is the artifactual staining of dead cells and clumps, which cannot be distinguished from viable cells on the basis of cell surface staining characteristics. We describe a method for simultaneous two color analysis or sorting of viable leukocytes which requires only a single laser. The method utilizes propidium iodide, which stains dead cells and thereby excludes such cells from the analysis. Using this method, as many as four viable cell types have been simultaneously analyzed in a single sample.

Utility of formaldehyde fixation for flow cytometry and inactivation of the AIDS associated retrovirus

To maximize safety in the setting of an increasing number of requests for flow cytometric analysis of specimens potentially contaminated with the AIDS retrovirus, we evaluated some commonly used fixatives for their ability to inactivate the infectious potential of the virus. We found that both formaldehyde (0.37% v/v) and paraformaldehyde (0.5% w/v) completely inactivated the infectious activity of both free and cell-associated lymphadenopathy associated virus (LAV), the etiologic agent for the acquired immunodeficiency syndrome (AIDS). Based on encouraging preliminary results we formally evaluated the effect of formaldehyde fixation on flow cytometric parameters. In addition to inactivating LAV, 0.37% formaldehyde in phosphate buffered saline preserved light scatter and fluorescence properties of cells stained with fluorescein isothiocyanate (FITC) and beta-phycoerythrin (PE) conjugated monoclonal antibodies. These findings suggest that formalin fixation may be useful for laboratories performing flow cytometric analysis of specimens potentially contaminated with the AIDS virus.

Defective cell-mediated immunity in leprosy: failure of T cells from lepromatous leprosy patients to respond to Mycobacterium leprae is associated with defective expression of interleukin 2 receptors and is not reconstituted by interleukin 2

Patients with lepromatous leprosy (LL) but not borderline tuberculoid leprosy (BT) have defective cell-mediated immune responses to Mycobacterium leprae, despite normal responses to other stimuli, as judged by in vivo skin testing and in vitro lymphocyte transformation. To investigate the basis of the immune defect in LL patients, we studied the ability of patient mononuclear leukocytes to produce interleukin 1 (IL 1) and interleukin 2 (IL 2) upon stimulation with M. leprae, and determined the ability of exogenous IL 1 and IL 2 to reconstitute the LL patient response to this antigen in vitro. Equal numbers of adherent non-T cells from LL and BT patients produced similar amounts of IL 1 upon challenge with M. leprae, and addition of IL 1 to the culture medium failed to reconstitute the response of lymphocytes from LL patients to M. leprae. On the other hand, T cells of LL patients failed to express receptors for IL 2 or to produce IL 2 in response to M. leprae, whereas similarly treated T cells of BT patients both expressed IL 2 receptors and produced IL 2. Finally, recombinant human IL 2 purified to homogeneity as well as crude supernatants of mitogen-activated lymphocytes failed to reconstitute the response of LL patients to M. leprae. These results suggest that T cells of LL patients fail to respond to M. leprae despite an ability to produce IL 1 and that their failure to express receptors for IL 2 may explain both defective proliferation and the failure of exogenous IL 2 to reconstitute the response.

Variables affecting T-lymphocyte subsets in a volunteer blood donor population

Inversion of the normal ratio of helper/inducer (Th) to suppressor/cytotoxic (Ts) T lymphocytes is a characteristic finding in symptomatic and presymptomatic patients with acquired immunodeficiency syndrome (AIDS). As an interim measure to prevent transmission of AIDS via blood transfusion, the Stanford Blood Center performed T-lymphocyte subset analysis as a screening procedure. In this report we present results from 8715 consecutive volunteer blood donors, aged 17-77. The mean Th:Ts ratio was 2.00 +/- 0.70 with a significant trend for increasing Th:Ts with increasing age. In all age groups, donors with antibody to cytomegalovirus (CMV) had lower Th:Ts ratios than CMV-seronegative donors. 1.9% of the donors had Th:Ts values less than or equal to 0.85 and blood from these donors was not used for clinical purposes. Compared to the overall donor population, individuals with Th:Ts less than or equal to 0.85 tended to be male, (79 vs 53%) and CMV sero-positive (71 vs 36%); a majority (83%) had a low absolute number of Th cells as well as a low Th:Ts value. Follow-up of donors with low Th:Ts values revealed that some belonged to AIDS high-risk populations, despite denials at the time of donation. One such donor was diagnosed with disseminated Kaposi's sarcoma 8 months after a markedly abnormal T-lymphocyte subset profile was noted during screening. These results suggest that T-lymphocyte subset analysis is capable of identifying at least some blood donors at risk for transmitting AIDS and also point to variable affecting T-cell subsets in apparently healthy blood donors.

Defective cell-mediated immunity in leprosy: failure of T cells from lepromatous leprosy patients to respond to Mycobacterium leprae is associated with defective expression of interleukin 2 receptors and is not reconstituted by interleukin 2

Patients with lepromatous leprosy (LL) but not borderline tuberculoid leprosy (BT) have defective cell-mediated immune responses to Mycobacterium leprae, despite normal responses to other stimuli, as judged by in vivo skin testing and in vitro lymphocyte transformation. To investigate the basis of the immune defect in LL patients, we studied the ability of patient mononuclear leukocytes to produce interleukin 1 (IL 1) and interleukin 2 (IL 2) upon stimulation with M. leprae, and determined the ability of exogenous IL 1 and IL 2 to reconstitute the LL patient response to this antigen in vitro. Equal numbers of adherent non-T cells from LL and BT patients produced similar amounts of IL 1 upon challenge with M. leprae, and addition of IL 1 to the culture medium failed to reconstitute the response of lymphocytes from LL patients to M. leprae. On the other hand, T cells of LL patients failed to express receptors for IL 2 or to produce IL 2 in response to M. leprae, whereas similarly treated T cells of BT patients both expressed IL 2 receptors and produced IL 2. Finally, recombinant human IL 2 purified to homogeneity as well as crude supernatants of mitogen-activated lymphocytes failed to reconstitute the response of LL patients to M. leprae. These results suggest that T cells of LL patients fail to respond to M. leprae despite an ability to produce IL 1 and that their failure to express receptors for IL 2 may explain both defective proliferation and the failure of exogenous IL 2 to reconstitute the response.

Production of functional human T-T hybridomas in selection medium lacking aminopterin and thymidine

The production of hybridomas between immunologically activated T cells and malignant T-cell lines offers a potentially unlimited source of soluble T-cell-derived products. Recently, human T-T hybrids have been described; however, their use has been hampered by slow growth and chromosomal instability due at least in part to the presence of thymidine in the traditional hypoxanthine/aminopterin/thymidine (HAT) selection medium. In this report, we describe the development of a rapidly growing hypoxanthine phosphoribosyltransferase-deficient human T-cell line designated J3R7, the use of azaserine/hypoxanthine (AH) medium as an alternative selection medium to HAT medium, and the production of functional T-T hybrids by using the J3R7 line and the AH selection technique. Hybrids selected in AH medium were 4-fold greater in number and 3-fold faster in growth rate than hybrids grown in HAT medium. No stable clones were obtained from HAT cultures whereas AH-derived hybrids could be readily cloned by the method of limiting dilution. Evidence for hybridization included (i) the presence of approximately twice the number of chromosomes in hybrids than in J3R7 cells; (ii) the presence on hybrid cells of the Leu-3a surface antigen, present on normal helper T cells but not on J3R7 cells; (iii) the expression of HLA antigens of both the normal T-cell partner and the J3R7 line; and (iv) the constitutive secretion of interleukin 2 from multiple hybrid clones but not from the J3R7 cell line. Thus far, these clones have maintained their rapid growth, chromosome number, surface phenotype, and constitutive secretion of interleukin 2 for 4 months.