Maternal IgG avidity and IgM detected by blot as diagnostic tools to identify pregnant women at risk of transmitting cytomegalovirus

In this study, we determined the avidity index (AI) of anticytomegalovirus (CMV) immunoglobulin G (IgG) and the anti-CMV immunoglobulin M (IgM) profile in 124 pregnant women, 87 of whom were considered at risk of transmitting CMV infection to their offspring and 37 of whom were at no risk. IgG avidity and blot for IgM were performed on two serum samples from each woman, at 6-18 weeks' gestation and at 20-23 weeks' gestation. Pregnancy outcomes were monitored. The results obtained showed that the determination of anti-CMV IgG avidity at 6-18 weeks' gestation can identify all women who would have an infected fetus/newborn (100% sensitivity), whereas IgM detected by blot had poorer results (69% sensitivity). Interestingly, at 20-23 weeks' gestation, the sensitivity of IgM detection by blot was higher than that obtained by avidity (75 % and 63%, respectively) and the combination of IgG avidity and IgM by blot yielded the best results (81% sensitivity).     

CD40 ligand-independent B cell activation revealed by CD40 ligand-deficient T cell clones: evidence for distinct activation requirements for antibody formation and B cell proliferation

We report the capacity of CD40 ligand (CD40L)-negative T cell clones to activate human B cells. CD40L-negative T cells induce a level of B cell proliferation 10–20% of that seen with normal T cells. The signal provided by the negative clones is synergistic with that derived from a CD40L transfectant, and restores B cell proliferation to normal levels, showing that CD40L-negative T cell clones are not inherently inhibitory for B cells. Although their capacity to induce proliferation was much reduced, CD40L-negative T cell clones were still strong inducers of B cell differentiation to plasma cells. This differentiation to plasma cells was inhibited by a CD40L transfectant. The data are discussed with regard to the normal in vivo mechanism for maintaining B cell memory and memory antibody responses to T-dependent antigens.     

Attachment,spreading and growthin vitro of highly malignant and low malignant murine fibrosarcoma cells

Highly malignant cell lines and low-malignant cell lines isolated from three different methylcholanthrene-induced murine fibrosarcomas were examined for their ability to attach to plastic dishes and collagen-coated dishes under serumfree conditions and in the presence of serum. Most of the cells from the three highly malignant lines attached and spread under all conditions. By 72h, there was a significant increase in the number of cells indicating that at least some of the cells had undergone division (even in the absence of serum). In contrast, fewer of the cells from the three low-malignant lines attached and spread on the plastic or collagen substrates in the absence of serum or in the presence of 0.1 per cent serum. However, when 15g laminin per dish was added along with the lowmalignant cells, they then attached and spread on the plastic and collagen-coated dishes. Previous studies have indicated that the highly malignant lines express cell surface antigens that cross-react with laminin while the low-malignant cell lines do not. We speculate that the differences between the high- and low-malignant cells in the expression of cell surface laminin-like antigens contribute to the dissimilarities in attachment and spreading capacity. These differences may also contribute to the dissimilarity between these cells in malignant potential.     

Reducing the time of sperm-oocyte interaction in human in-vitro fertilization improves the implantation rate

Human oocyte development was evaluated after a reduced timeexposure to spermatozoa in vitro. A total of 119 patients wereassigned to two study groups in a randomized prospective studyin which each patient‘s oocytes were exposed to spermatozoafor either 1 h (group 1 – 58 patients) or the standard16 h incubation period (group 2 – 61 patients). The fertilizationrate obtained in group 1 was higher than in group 2 (285/393,73%, and 272/410, 66% respectively), suggesting that the spermatozoa-oocyteinteraction occurs within 1 h. This was confirmed in a studyin vitro using fluorescently labelled spermatozoa and normaloocyte-cumulus complexes. Spermatozoa enter the cumulus complexwithin 15 min, traverse the cumulus layer within 3 h, and firstappear in the oocyte cortex at 4 h post-insemination. The incidenceof polyspermy was higher in oocytes exposed to spermatozoa for16 h (3%) than for 1 h (1%). There was no difference in thecleavage rate or morphological characteristics of embryos fromboth study groups. However, when evaluating the timing of embryodevelopment, group 1 generated a significantly higher percentageof four to five cell embryos when compared to group 2 (55 versus39%; P < 0.001), documented at 40 h post-insemination. Theimplantation and pregnancy rates for group 1 were 11 and 28%,while the corresponding rates for group 2 were 8 and 15%. Thissuggests that a reduced exposure of oocyte to spermatozoa favoursembryo viability, possibly due to a decrease in potential damagefrom sperm metabolic waste products.     

Type I interferon gene transfer sensitizes melanoma cells to apoptosis via a target activity on mitochondrial function

Our previous article reported that retroviral transduction of human type I consensus interferon-coding sequence into two human melanoma cells increased their susceptibility to cisplatin-induced apoptosis. Importantly, primary melanoma cells were significantly more sensitive to cisplatin-induced apoptosis with respect to metastatic melanoma cells. The aim of this study was to elucidate the subcellular mechanisms involved in this interferon-induced apoptotic proneness. Our results indicate that 1) cisplatin-induced apoptosis can be referred to as the type II apoptosis, ie, to the mitochondrially driven cascade; 2) treatment of interferon-producing melanoma cells with other type II apoptotic stimuli, such as radiation or staurosporine, also resulted in massive apoptosis, whereas type I stimuli, ie, anti-Fas, were ineffective; 3) interferon sensitization involved the caspase cascade in primary melanoma cells and the alternative pathway represented by cathepsin-mediated apoptosis in metastatic melanoma cells; 4) interferon production sensitizes cells to apoptosis by inducing, as the earliest event, mitochondrial membrane hyperpolarization. These results suggest that constitutive production of type I interferon by melanoma cells can act as an intracellular booster capable of increasing cell proneness to apoptosis by specifically modifying mitochondrial homeostasis and independently from the apoptotic cascade involved.     

Modulation of keratinocyte motility. Correlation with production of extracellular matrix molecules in response to growth promoting and antiproliferative factors.

Normal human epidermal keratinocytes (KC) grown under conditions that maintain the undifferentiated state are highly motile. Migration of these cells as measured in two different assays (migration out of an agarose drop explant, and into micropore filters in a modified Boyden chamber), is stimulated by fibronectin (FN) and to a lesser extent by thrombospondin (TSP). In contrast, laminin (LN) inhibits KC migration. Cultivation of the cells for 1 day under conditions that induce differentiation (ie, in the presence of 1.4 mM Ca2+) suppresses KC motility. A number of soluble growth modulating polypeptide factors also influence KC migration. Transforming growth factor-beta (TGF-beta) and epidermal growth factor (EGF) stimulate KC motility. These factors simultaneously induce KC production of FN and a significant portion of the stimulated motility can be inhibited with antibodies to FN. EGF and somatomedin-C (SM-C), but not TGF-beta, also stimulate TSP production while EGF and SM-C (but not TGF-beta) induce KC proliferation. In contrast to these factors, interferon-gamma (INF-gamma) inhibits KC production of both FN and TSP and concomitantly inhibits both motility and proliferation. These data suggest that KC properties essential for normal wound healing (ie, motility and proliferation) are regulated by both extracellular matrix molecules and soluble peptide factors. Finally, these effects of various growth promoting and antiproliferative factors on KCs may, in part, be mediated through alteration in the endogenous production of extracellular matrix molecules by KCs.     

Comparison of the chemotactic responsiveness of two fibrosarcoma subpopulations of differing malignancy.

There are several points of similarity between the processes of cancer metastasis and inflammation. In both, cells circulate in the vasculature, arrest, and cross vessel walls, thereby entering the extravascular tissues. In vitro, leukocytes and some, but not all, tumor cells exhibit chemotaxis. Since the chemotactic response of leukocytes effect their transvascular migration, we propose that chemotactic responsiveness contributes to the ability of circulating tumor cells to localize in extravascular tissues. This study was done to seek a relationship between chemotactic responsiveness of tumor cells and their behavior in vivo. Two subpopulations of cells were isolated from a methylcholanthrene-induced fibrosarcoma. The two cell lines were compared with regard to their biologic behavior in vivo and their chemotactic responsiveness in vitro. In vivo one subpopulation was highly malignant. An injection of 2.0 x 10(5) cells into the footpad of syngeneic mice led to the development of primary tumors in 87% of the animals and lung metastases in 61% of the animals with primary tumors. This line demonstrated chemotaxis to a factor that behaved similarly in gel filtration and showed immunologic reactivity similar to that of a previously described tumor cell chemotactic factor derived from the fifth component of complement. In contrast, an injection of the same number of cells from the second subpopulation of fibrosarcoma cells led to the development of primary tumors in only 12% of syngeneic mice, and lung metastases did not occur. Neither this subpopulation nor normal embryonic fibroblasts demonstrated chemotactic responsiveness. We postulate that the ability of tumor cells to respond to specific chemotactic stimuli may be one of the many unique properties which distinguish malignant from benign tumor cells. This is the first report documenting the chemotactic responsiveness of non-ascites tumors and fibrosarcomas.     

Characteristics of the chemotactic response of neoplastic cells to a factor derived from the fifth component of complement.

Chemotactic factors for malignant neoplastic cells can be generated from either the fifth component of complement or from leukotactic fractions obtained from zymosanactivated serum. Digestion of the fifth component of complement by trypsin initially produced leukotactic activity, but as digestion continues, leukotactic activity is lost and tumor cell chemotactic activity is generated. Separation of the leukotactic activity is lost and tumor cell chemotactic activity is generated. Separation of the leukotactic activity and tumor cell chemotactic activity can be accomplished by gel filtration or isoelectric focusing. Gel filtration indicates that the tumor cell chemotactic factor has a molecular weight of approximately 8000 daltons. Tumor cell chemotactic activity can be generated by trypsinizing the leukotactic fractions isolated by isoelectric focusing. The responses of cultured Walker tumor cells or of Walker ascites tumor cells are dose-dependent and truly chemotactic. Cells from a murine malignant lymphoma do not respond to the complement-derived chemotactic factor for tumor cells, indicating that not all malignant cells share this functional property.     

Peripheral cytokine release in Alzheimer patients: correlation with disease severity

Various studies suggested that inflammation is involved in the pathogenesis of Alzheimer's disease (AD). We investigated cytokine release from LPS-stimulated blood cells of 32 AD patients, with different disease severity, compared to 16 age-related controls. A significant decrease of IL-1beta and IL-6 secretion was observed in severely demented patients; TNF-alpha release was also decreased, but not significantly. By contrast, mild and moderate patients showed a cytokine release similar to controls. IL-1beta, IL-6 and TNF-alpha secretion was negatively correlated with the severity of dementia, quantified by the MMSE. Our data suggest that alterations of the immune profile are associated with AD progression.     

Relationships between total plasma load of torquetenovirus (TTV) and TTV genogroups carried

In 239 torquetenovirus-positive people, multiple-genogroup infections were common and associated with higher viral loads than would be expected from simple additive effects. The latter observation was restricted to the infections which included both genogroups 1 and 3, pointing to the possible existence of some kind of infection facilitation between these genogroups.