A metalloproteinase inhibitor blocks the shedding of soluble cytokine receptors and processing of transmembrane cytokine precursors in human monocytic cells.

A number of membrane-anchored cytokines and cytokine receptors are susceptible to yield soluble counterparts. Recently, peptide-hydroxamate metalloproteinase inhibitors have been reported to block the proteolytic processing of tumour necrosis factor (TNF)-alpha 55- and 75-kDa TNF receptors (TNF-R55 and TNF-R75), and interleukin (IL)-6R. In this report the authors studied the effect of an hydroxamate metalloproteinase inhibitor on the secretion of cytokines and the generation of cytokine soluble receptors by human myelomonoycytic cell lines and purified monocytes. Whereas secretion of cytokines lacking a transmembrane domain precursor (IL-1 alpha, IL-1 beta, IL-6 or IL-10) is either unaffected or augmented, shedding/secretion of transmembrane domain-containing cytokines and cytokine receptors [TNF-alpha, macrophage colony-stimulating factor (M-CSF), transforming growth factor (TGF)-alpha, stem cell factor (SCF), TNF-R55, TNF-R75, and IL-6R] was dramatically decreased in the presence of the metalloproteinase inhibitor. The diversity of sequences in the cleavage site of these proteins and differences found in the inhibitory concentration values suggest the existence of a metalloproteinase family displaying different substrate specificity. These results emphasize the important role of metalloproteinases as regulators of membrane expression and secretion of cytokines and cytokine receptors.

In vivo local expansion of clonal T cell subpopulations in renal cell carcinoma.

Renal cell carcinoma (RCC) is one human tumor to which the immune response may control the growth of tumor cells. These tumors are infiltrated by a large mononuclear infiltrate mainly composed of T lymphocytes. To characterize the lymphocytes infiltrating RCC, we analyzed the molecular structure of the T cell receptor (TCR) alpha and beta chains in tumor and paired peripheral blood lymphocytes from a series of 6 untreated patients. We first determined V alpha and V beta gene segment usage by PCR using a panel of V specific oligonucleotide primers (V alpha 1-w29 and V beta 1-w24). A highly diverse usage of TCR V alpha and V beta gene usage was observed in 5 of 6 tumors. In addition, the few tumor overexpressed V beta specificities detected by reverse transcription-PCR were shown to contain minor T cell expansions. Strikingly, 1 of the 6 tumor studied displayed a skewed TCR repertoire with V beta 4 transcript representing 25% of the TCR signals. Clonality of the tumor overexpressed V beta transcripts was analyzed by CDR3 size distribution analysis. In the particular tumor displaying a biased repertoire large expansions of T cell subpopulations were detected (particularly in V beta 4) specifically at the tumor site. Such T cells may be expanded locally in response to tumor antigens.

[Comparative study of minimal inhibitory concentration (MIC) and minimal lethal concentration (MLC) values for tetracycline, monocycline, erythromycin and rokitamycin against eleven strains of Chlamydia trachomatis]. / Etude comparative des concentrations minimales inhibitrices (CMI) et des concentrations minimales léthales (CML) de la tétracycline, de la minocycline, de l'érythromycine et de la rokitamycine sur onze souches de Chlamydia trachomatis.

We evaluated the efficacy of tetracycline, minocycline, erythromycin and rokitamycin (rikamycine, TMS-19Q) in controlling in vitro propagation of Chlamydia trachomatis in HeLa 229 cells. Ten recent clinical isolates of Chlamydia trachomatis and one fast-growing strain were tested with inocula of 100-1,000 inclusion forming units per well of a 96-wheel microculture plate. Chlamydia trachomatis inclusions were detected by an immunoperoxidase-antiperoxidase procedure (PAP), including a genus-specific monoclonal antibody. Minimal inhibitory concentration (MIC) geometric means and ranges were respectively 0.128, 0.015-0.25 mg/l tetracycline, 0.001, less than or equal to 0.001-0.004 mg/l minocycline, 0.187, 0.031-0.5 mg/l erythromycin, and 0.005, less than or equal to 0.001-0.062 mg/l rokitamycin; minimal lethal concentration (MLC) geometric means and ranges were 6.79, 0.125-32 mg/l tetracycline, 0.225, 0.062-2 mg/l minocycline, 3.37, 1-32 mg/l erythromycin, and 0.112, 0.031-1 mg/l rokitamycin. Since rokitamycin appears to be the more bactericidal from the four antibiotics tested, clinical studies in sexually transmitted diseases are indicated.