Marrow stroma has been shown to have osteogenic potential. Here we report the characterization of a unique stromal cell line derived from mouse bone marrow (MBA-15), which expresses osteoblastic phenotype in vitro and forms bone in vivo. More than 70% of cells in culture were histochemically positive for alkaline phosphatase. The enzyme levels were enhanced threefold when cultures were treated with dexamethasone. Gel electrophoresis of [3H]-proline-labeled cultures showed that MBA-15 cells produced only type I collagen. These cells were responsive to PTH, as indicated by a 50-fold increase in intracellular cAMP. Prostaglandin E2, but not calcitonin, stimulated cAMP up to 70-fold. When cultures were grown to confluence and fed daily with ascorbic acid and beta-glycerophosphate, the cells formed a Von Kossa positive, thick extracellular matrix, shown to contain hydroxyapatite crystals. MBA-15 cells produced mineralized bone when implanted in diffusion chambers. These results indicate that the MBA-15 cell line possesses osteoblastic features in vitro and osteogenic capacity in vivo.

A highly specific enzyme immunoassay (EIA) was recently described for use in the diagnosis of cat scratch disease (CSD). However, data regarding EIA antibody kinetics or its correlation with long-term clinical follow-up data are lacking. The association between antibody kinetics, clinical spectrum, and disease duration were studied in 98 patients with CSD. The median duration of follow-up was 35.3 weeks (range, 2-211.3 weeks). Results of EIA testing for detection of anti-Bartonella henselae immunoglobulin M (IgM) antibodies (detected in 53% of the patients) remained positive for < or =3 months. Therefore, the presence of IgM indicated acute infection. Titers of immunoglobulin G (IgG) also decreased over time; 25% of the patients remained seropositive for >1 year after the onset of CSD. Onset of CSD in patients with an IgG titer with an optical density of > or =1.0 occurred within the prior 12 months. No association was found between antibody titers or their kinetics and the clinical manifestations or duration of disease. EIA allows for the identification of atypical manifestations of CSD that were unrecognized before the use of serological assays. Complete recovery from these manifestations may take months. Results of this study provide additional data supporting the utility of EIA in the serodiagnosis of CSD.

Whole-cell immunofluorescent antibody (IFA) tests for detection of anti-Bartonella henselae immunoglobulin (Ig) G are commonly used to diagnose cat-scratch disease (CSD). The need to cultivate B. henselae in Vero cells for antigen preparation and the absence of routinely applied IFA assays for IgM constitute the major disadvantages of this form of test. We describe the results of an enzyme immunoassay (EIA) for IgM and IgG that used N-lauroyl-sarcosine-insoluble outer membrane antigens from agar-grown B. henselae performed in 84 patients with definite CSD (regional lymphadenitis, cat contact, and > or =1 confirmatory test: polymerase chain reaction, skin test, or B. henselae culture). Although this method has been used as a diagnostic tool in several case reports, it has not previously been evaluated in a large study of definitively proven CSD cases. Results of this study indicate that the EIA described herein can play an important role in the serodiagnosis of CSD, although improvement of the sensitivity, particularly that of the IgM, would be desirable.

In a previous study, moxifloxacin was shown to ameliorate immunosuppression and enhance cytokine production in several tissues, including the lungs of cyclophosphamide-injected mice. We examined here the effects of moxifloxacin on Candida albicans lung infection in cyclophosphamide-injected mice. Mice were injected on day 0 with 250 mg of cyclophosphamide/kg, and on days 1 to 4 they were given moxifloxacin at 22.5 mg/kg/day compared to controls given ceftazidime at 75 mg/kg/day or saline. On day 6, C. albicans (10 7 CFU/ mouse) was inoculated intratracheally, and animals were observed for the development of bronchopneumonia, weight loss, mortality, the presence of C. albicans, and lung cytokine production. Histopathology on day 10 postinoculation revealed bronchopneumonia in 50, 67, and 0% of saline-, ceftazidime-, and moxifloxacintreated mice, respectively (P < 0.05). The mortality rates were 28, 17, and 5%, respectively (P < 0.05), and weight loss occurred at 20, 32, and 0%, respectively (P < 0.05). By day 15, C. albicans was eliminated from all moxifloxacin-treated mice but was still isolated from lung homogenates of 50 to 60% of the saline-and ceftazidime-treated groups. Among the cytokines tested on days 0 to 15, we found an increased production of tumor necrosis factor alpha, KC (functional interleukin-8), and gamma interferon in the lungs of ceftazidimeand saline-treated controls compared to the moxifloxacin pretreatment that abolished their secretion. In conclusion, moxifloxacin protected cyclophosphamide-injected mice from C. albicans-induced lung infection and significantly reduced pneumonia, weight loss, and mortality despite the lack of direct antifungal activity. This is most likely due to an immunomodulating activity conferred by moxifloxacin, as shown in this model and in our previous studies. Its potential protective role should be studied in patients undergoing chemotherapy and immune suppression.

We compared the effect of haematopoietic growth factors granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin (IL)-1, IL-3, and IL-5 on the functional activation of human eosinophils and neutrophils from the same donor. All four colony-stimulating factors (CSF) enhanced the phagocytosis of Candida albicans by eosinophils and increased staphylococcal, but not Candida, killing. GM-CSF and IL-5 had a profound stimulating effect on eosinophil staphylocidal activity. GM-CSF and IL-3 enhanced the generation of leukotriene C4 (LTC4) induced by calcium ionophore A23187 and the release of arylsulphatase and beta-glucuronidase from specific and small granules of eosinophils. In contrast, IL-1 and IL-5 had no effect on degranulation. GM-CSF and IL-1 enhanced phagocytosis of C. albicans by neutrophils, and GM-CSF stimulated degranulation and the release of the enzymes beta-glucuronidase and arylsulphatase from neutrophils while IL-1 stimulated the release of arylsulphatase only. This study indicates that the eosinophil-active colony-stimulating factors can markedly enhance the host defence function of the eosinophil and even make it the equal of the neutrophil in staphylocidal activity. The CSF-activated eosinophil, however, may cause inappropriate inflammation and normal tissue damage.