Floyd E. Fox

Regulation of cytokine expression in macrophages and the Langerhans cell-like line XS52 by calcitonin gene-related peptide.

Calcitonin gene‐related peptide (CGRP) inhibits antigen presentation by Langerhans cells (LC) and macrophages, and LC are anatomically associated with CGRP‐containing epidermal nerves. To determine whether CGRP may produce some of its functional effects through regulation of cytokine expression, we utilized enzyme‐linked immunosorbent assay (ELISA) of conditioned supernatants to examine production of interleukin (IL)‐10 and IL‐1β protein in the LC‐like cell line XS52 as well as the reverse transcriptase‐polymerase chain reaction (RT‐PCR) to examine levels of mRNA for IL‐10, IL‐1β, and the 40‐kDa subunit (p40) of IL‐12. CGRP augmented the lipopotysaccharide (LPS) and granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) ‐induced release of IL‐10 protein and the induced expression of IL‐10 mRNA in these cells. However, it suppressed the induction of release of IL‐1β protein and the induction of mRNA for IL‐12 p40 and IL‐1β by LPS and GM‐CSF. Regulation of cytokine expression in peritoneal macrophages was also examined. By ELISA, the LPS‐induced expression of IL‐10 was augmented by CGRP, whereas the induction of IL‐1β was suppressed. Northern analysis demonstrated augmentation of LPS‐induced IL‐10 mRNA levels and inhibition of LPS‐induced IL‐1β mRNA by CGRP. CGRP inhibited the LPS‐induced induction of IL‐12 mRNA as assessed by RT‐PCR. Up‐regulation of B7‐2 expression by LPS and GM‐CSF was suppressed by CGRP in both XS52 cells and macrophages, as previously reported. This suppression, however, could be abrogated by co‐culture with neutralizing antibodies to IL‐10. Furthermore, the presence of neutralizing antibodies to IL‐10 during exposure of epidermal cells (EC) to CGRP prevented the CGRP‐mediated suppression of EC presentation of tumor‐associated antigens (from the S1509a spindle cell carcinoma) for elicitation of delayed‐type hypersensitivity in S1509a‐immune mice. These data suggest that suppression of antigen‐presenting function by CGRP is mediated, at least in part, by changes in cytokine expression that favor less robust antigen presentation for cell‐mediated immunity. J. Leukoc. Biol. 61: 216–223; 1997.

Induction of metalloproteinase activity in human T-lymphocytes.

Matrix metalloproteinases are thought to play major roles in a wide array of normal and pathological processes. These proteinases are involved in the degradation of the extracellular matrix and are believed to facilitate the movement of cells from one site to another. In the current study, we examined the expression of the 92 kDa gelatinase activity (MMP-9) by the human T-lymphoma cell line, HSB. Proteinase activity was greatly elevated when cells were treated with TPA. This induction was initially observed at 6 h post-TPA treatment and continued to increase up to 48 h. Proteinase induction was inhibited by actinomycin D and cycloheximide, indicating that nascent RNA and protein synthesis were required. Staurosporine, an inhibitor of protein kinase C activity, suppressed the TPA-induction of gelatinase activity. Our results suggest that TPA induces the 92 kDa gelatinase activity by activating protein kinase C. TGF-beta also induced proteinase activity, although to a lesser extent than TPA. Several criteria indicate that this enzyme is a member of the family of matrix metalloproteinases: (1) this activity was inhibited by EDTA, 1,10-phenanthroline and TIMP; (2) this activity bound to a gelatin-agarose affinity resin; (3) it has a mass of approx. 92 kDa on SDS-polyacrylamide gels; (4) it cleaves gelatin and (5) the inducible proteinase cross reacts with antiserum to MMP-9.

The potential therapeutic role of interleukin-12 in cutaneous T-cell lymphoma.

Cutaneous T-cell lymphoma (CTCL) is a lymphoproliferative disorder characterized by skin invasion of clonally derived malignant CD4+ lymphocytes that phenotypically resemble mature T-helper (Th) cells. Sezary syndrome (SzS) represents an advanced form of CTCL associated with generalized erythroderma and involvement of the peripheral blood by the malignant cell population. We have previously demonstrated aberrant cytokine production by peripheral blood mononuclear cells (PBMCs) in SzS characterized by increased IL-4 and deficient IL-2 and IFN-gamma production, as well as increased expression of mRNA for IL-4 and IL-5 within active skin lesions, indicating that the clonal T-cell population is likely derived from the T-helper type 2 (Th2) subset of helper T lymphocytes. Furthermore, a variety of immune abnormalities have been observed in association with SzS that have been attributed to the cytokine abnormalities. Because IL-12 is a potent inducer of IFN-gamma production and causes the activation of cytotoxic lymphocytes, we assessed the production of IL-12 by PBMCs from SzS patients, and whether IL-12 could alter the unfavorable cytokine balance typical of SzS and, thus, possibly lead to correction of immune defects. In this review, we present our data, which indicate that patients with SzS exhibit marked defects in monocyte production of IL-12 p70. Moreover, in vitro culture of PBMC from SzS patients with recombinant IL-12 leads to reconstitution of normal IFN-gamma production and markedly enhances cell-mediated cytotoxicity.

Use of biological response modifiers in the treatment of cutaneous T-cell lymphoma.

Cutaneous T-cell lymphoma (CTCL) is typically a skin-infiltrating, clonal proliferative disorder of CD4+ T cells that exhibit a T-helper type 2 cytokine phenotype. Therapeutic decisions are based on the extent of disease and the observations that host-antitumor responses occur and that these responses may be blunted by the immunosuppressive cytokines produced by the malignant T cells. Biologic response modifiers, which may enhance cell-mediated immunity and antitumor responses, are active agents in the treatment of CTCL. The rationale and use of biologic response modifiers to treat CTCL are reviewed in this article.

Richter's syndrome associated with loss of response to transforming growth factor-beta☆

A patient with chronic lymphocytic leukemia developed a large cell lymphoma apparently derived from the same neoplastic B-cell clone (Richters syndrome). At the same time, mitogen-stimulated proliferation of the patients circulating leukemic B-cells was no longer inhibited by the regulatory cytokine transforming growth factor-beta (TGF-beta), suggesting that such loss of inhibition might be contributing to the clinical and biological progression of the disease.