Characterization of cytoplasmic and nuclear polypeptides induced by interferon-gamma in a murine pre-B cell leukemia

The effects of interferon-gamma (IFN-gamma) on protein synthesis of a pre-B cell leukemia, L1210, have been studied by two-dimensional gel electrophoresis. In total cell extracts, at least ten proteins were induced de novo, or increased in their expression, after an 18-h IFN-gamma treatment, whereas in the nuclear extracts eight proteins were specifically induced. Of these, increased synthesis of a 40-kDa/pI 5.9 cytoplasmic protein was the most prominent and reproducible. Most of these proteins appear to be specific for a defined step of differentiation, since they are not found in other B cell leukemias upon IFN-gamma treatment. Others appear to be tissue specific, since they are not induced in fibroblasts nor in T cells. In addition, synthesis of some of the induced proteins appeared to require rapid transcription of new mRNA, because actinomycin D markedly inhibited their formation when added immediately before IFN-gamma. In keeping with this finding, in vitro translation of mRNA from IFN-gamma-treated L1210 cells into a rabbit reticulocyte lysate system, followed by analysis of the labeled proteins by two-dimensional gel electrophoresis, revealed the appearance of at least seven proteins. Taken as a whole, these results demonstrate that in leukemic pre-B cells IFN-gamma induces the transcriptional activation of genes coding for cytoplasmic and nuclear proteins, some of which could be employed as specific cell activation markers.

[Treatment of deep venous thrombosis. Comparative study of a low molecular weight heparin fragment (Fragmin) by the subcutaneous route and standard heparin by the continuous intravenous route. A multicenter study]

This open, randomised multicenter trial compares the efficacy and safety of Fragmin administered subcutaneously twice daily with standard heparin administered by continuous infusion in the treatment of deep vein thrombosis (DVT). The initial dose of Fragmin is 100 U anti-Xa/kg/12 h and the further doses are adjusted according to the anti-Xa activity between 0.5 and 0.8 U/ml, 3 hours after the morning injection. The initial dose of standard heparin is 240 UI/kg/12 h. The dose adjustments are based on the daily results of APTT (1.5 - 3 times the control). Treatments efficacy are appreciated when comparing the venography performed before and after 10 days of treatment. The safety is evaluated on clinical parameters and iterative biological tests. Sixty-six patients have been included in this study. Efficacy of the two treatments is equivalent with a phlebographic improvement in respectively 79.3 p. 100 (Heparin Group) and 71.0 p. 100 (Fragmin Group) of the cases and an aggravation in 3.4 p. 100 and 6.4 p. 100 (NS) respectively. The frequency of dosage adjustments is lower and the stability of biological tests is better in the Fragmin group. In conclusion, the administration of Fragmin twice daily by subcutaneous route seems to be equivalent at least to standard heparin continuous infusion in the treatment of recent DVT. The better convenience and safety of Fragmin have to be verified on a larger panel of patients.

Evidence for a GTP-binding protein involved in interferon-gamma transduction signal

These studies were designed to investigate the characteristics of the intracellular messengers induced by interferons (IFN-alpha/beta and IFN-gamma) after receptor binding. Pretreatment of target cells with V. cholerae toxin, which is known to activate a membrane GTP-binding stimulatory protein (Gs), potentiated the action of IFN-gamma, but not of IFN-alpha/beta. By contrast, B. pertussis toxin, which is known to activate the GTP-binding inhibitory protein (Gi), had no effects on the action of both IFN-alpha/beta and IFN-gamma. Further support to the involvement of G proteins in IFN-gamma transduction signal came from the finding that a non-hydrolizable GTP analog, GTP-gamma-S, enhanced in the presence of phorbol esters (PMA) the antiviral and antiproliferative activity of IFN-gamma, but not of IFN-alpha/beta. On the other hand, forskolin or PGE1, known to increase the intracellular cAMP levels by different metabolic pathways, when added together with IFN-gamma, significantly potentiated its antiviral and antiproliferative activity. Pretreatment of the cultures with the above drugs completely prevented IFN-gamma activity. No effects were observed when forskolin or PGE1 were used with IFN-alpha/beta. Finally, the modulation of IFN-gamma activity by the above drugs was not a consequence of changes in the expression of the specific surface receptors, since [125I]IFN-gamma binding by pretreated target cells was comparable to that of untreated cultures. Altogether these results demonstrate that the IFN-gamma, but not the IFN-alpha/beta, transduction signal is mediated after receptor binding by a G protein with functional characteristics similar to those of the known Gs proteins. Activation of the adenylate cyclase system could be one of the subsequent steps involved in IFN-gamma action.

Expression of class I and class II major histocompatibility complex antigens on human hepatocytes

We analyzed whether normal human hepatocytes, which normally do not display Class II major histocompatibility complex antigens, can be induced to express them in vitro, and whether this induction has an in vivo counterpart in chronic liver diseases. While both alpha- and gamma-interferon induced expression of Class I antigens, only gamma-interferon induced expression of Class II antigens on hepatocytes in vitro. Recombinant interleukin 2 had no effect on major histocompatibility complex antigen expression. Both Class I and Class II antigens could be detected by indirect immunofluorescence on hepatocytes from patients with various forms of chronic liver disease, regardless of etiology. These findings suggest that gamma-interferon produced by T lymphocytes that infiltrate the liver during the course of chronic hepatitis induces Class II major histocompatibility complex antigen expression and may endow the hepatocytes with the capacity to perform accessory (antigen-presenting) cell functions.

A synthetic vaccine protects humans against challenge with asexual blood stages of Plasmodium falciparum malaria

We have previously shown that a mixture of three synthetic peptides (83.1, 55.1, 35.1), corresponding to fragments of the relative molecular mass 83,000 (83K), 55K and 35K Plasmodium falciparum merozoite-specific proteins, induces protection in Aotus triviroatus monkeys experimentally infected with P. falciparum. Here we describe two polymeric synthetic hybrid proteins based on these peptides that delay or suppress the development of parasitaemia in immunized human volunteers.

"Anti-Ia reactivity in sera from patients with chronic active hepatitis (CAH)"

Anti-Ia reactivity in sera from patients with chronic active hepatitis (CAH) were characterized by determining cross-reacting specificities with the antigen defined by anti-Ia monoclonal antibody (MoAb) and by studying the effect of CAH sera on the autologous mixed leukocyte reaction (MLR). Preincubation with autoimmune CAH sera lowered the percentage of Ia+ non-T cells stained by anti-Ia MoAb. HBsAg+ve/HBeAg+ve sera did not exert any blocking activity while 4 out of 11 HBsAg+ve/anti-HBe+ve sera exerted a significant blocking effect. Preincubation of cells with normal human serum (NHS) plus aggregated IgG did not block the binding of MoAb anti-Ia. Sera from patients with autoimmune or HBsAg+ve/anti-HBe+ve CAH, that blocked the binding of anti-Ia MoAb to Ia positive target cells by more than 20%, clearly inhibited the autologous mixed lymphocyte reaction (MLR). Both IgG and IgM fractions obtained by affinity chromatography from CAH sera inhibited the autologous MLR and blocked the binding of anti-Ia antibody to Ia positive target cells. A significant positive correlation (p less than 0.001) between serum anti-Ia reactivity and serum liver membrane antibodies (LMA) was observed. In 4 "autoimmune" CAH patients, steroid treatment induced a dramatic decrease in the anti-Ia reactivity.

[Value of venous ultrasonic tomography in the screening for unusual emboli-causing foci]

In certain cases of pulmonary embolism, phlebography of the lower extremities remains normal. The study of 219 consecutive cases of pulmonary embolism shows the advantage of venous ultrasonic tomography which, alone, enables to screen the embolic focus in 10% of the cases, either because the phlebographic data are insufficient (5%), or because the embolic focus cannot be reached with phlebography (5%), especially in deep femoral and internal saphenous thromboses. On the other hand, popliteal venous aneurysms, which represent 1% of all embolic foci in this study, are always discovered by ultrasonography. Therefore this technique appears absolutely necessary for the diagnosis of an embolic venous focus.

Class II MHC antigen expression on epithelial cells of salivary glands from patients with Sjögren's syndrome

Class II MHC molecules are two-chain glycoproteins normally expressed only on the membrane of cells involved in the immune response. These molecules are restriction elements for helper T cells. Using indirect immunofluorescence on cryostat sections of biopsied salivary glands we have demonstrated epithelial expression of class II antigens in patients with Sjögren's syndrome. The HLA DR+ epithelial cells were seen in close proximity to lymphocyte infiltrates. The finding that class II molecules are also expressed in salivary glands without focal lymphocytic infiltrates suggests a "modulation" as opposed to "induction" of HLA DR antigens on epithelial cells in Sjögren's syndrome, the distinction being related to the enhancement of low levels of expressions vs. de novo synthesis.

Semiological analysis of Raynaud attacks

Careful semiological and etiological investigations (including nailfold capillary microscopy) were performed in 120 consecutive patients with Raynaud phenomenon (RP) (December 1983-March 1984) recorded on a standardized form. Complete and reliable data were obtained in 103 cases. The functional severity of the attacks was assessed statistically, after adjusting for etiological groups. The existence of an asphyxial (cyanotic) phase was found the best single criterion for the severity of attacks, but a more complete evaluation was arrived at with the following functional severity score (FSS = 0 to 3): asphyxia (0 or 1)+summer rate of attacks higher than once a week (0 or 1)+involvement of all the fingers (0 to 1). This score was also validated through a multivariate correspondence analysis. FSS was much higher in RP associated with connective tissue diseases (1.73 +/- 0.18) than in primary RP (0.64 +/- 0.14, p less than 0.001). A careful analysis of ischemic attacks is thought to be an important part of etiological and pre-therapeutic evaluation of patients with RP.

[Cefonicid toxicity. I. Effects on the reactivity of the specific immune system]

The degree of toxicity of the antibiotic Cefonicid on the cellular reactivity of the immune system was evaluated. The effects on some lymphokine (IL-2 and IFN-gamma) production and the degree of proliferation of splenic lymphocytes following mitogen stimulation have been considered. Our results show that Cefonicid does not impair the immune response, except at very high doses (500 micrograms/ml).

[Periungual capillaroscopy in rheumatoid arthritis. Prospective study of 80 cases]

This study involved the screening for dermal microcirculatory abnormalities using periungueal capillaroscopy in a group of 80 cases of rheumatoid arthritis, so-defined in terms of ARA criteria. Excessive erythrocyte aggregation and/or pericapillary edema were detected in 74% of cases and were statistically correlated with ESR, reflecting an inflammatory syndrome. Capillary neogenesis, probably in reaction to subclinical cutaneous vascularity, was detected in 59% of cases (86% of subjects presenting extra-articular rheumatism). In 28% of cases this was accompanied by spontaneous hemorrhage, suggesting a progressive condition. Stigmata of cutaneous atrophy were present in 54% of subjects. These findings demonstrate the frequency of subclinical cutaneous damage in rheumatoid disease and suggest the possibility of the clinical usefulness of capillaroscopy, a non-invasive technic, in the follow-up of this disease.

Cholinergic modulation of an acetylcholine receptor-like antigen on the surface of chick ciliary ganglion neurons in cell culture

Chick ciliary ganglion neurons have a membrane component that shares an antigenic determinant with the "main immunogenic region" of the alpha subunits in nicotinic ACh receptors from skeletal muscle and electric organ. Ultrastructural studies on antibody binding in the ganglion have shown that the cross-reacting antigen on the neuron surface is located predominantly in synaptic membrane. Biochemical studies have shown that the cross-reacting component has a number of other properties expected for the ganglionic nicotonic ACh receptor and that it is distinct from the alpha-bungarotoxin binding component in the tissue. Here we show that ciliary ganglion neurons grown in dissociated cell culture express a similar component that cross-reacts with monoclonal antibodies to ACh receptors, and that the number of antibody-binding sites on the neurons can be modulated by exposure to cholinergic agonists and a protein neurotoxin that reversibly inhibits ACh receptors on the neurons. In most, though not all, cases, levels of ACh sensitivity associated with the neurons are specifically comodulated in parallel with the changes in number of antibody binding sites. The results suggest that at least a portion of the cross-reacting sites on the surface of ciliary ganglion neurons is likely to represent nicotinic ACh receptors. The fact that in some instances levels of ACh sensitivity can be altered without changing the number of cross-reacting sites, however, leaves open the possibility that not all of the sites are associated with receptors or that the neurons can alter the proportion of receptors that is functional.

Characterization of effector cells in lymphocytotoxicity to autologous hepatocytes in HBsAg-positive and autoimmune chronic active hepatitis (CAH)

Peripheral blood lymphocyte subsets involved in cytotoxicity to autologous hepatocytes have been characterized by isolation on antibody-coated Petri dishes in autoimmune and HBsAg-positive chronic active hepatitis (CAH). In autoimmune CAH and in HBsAg-positive CAH without HBcAg in liver tissue, cytotoxicity is sustained by non-T lymphocytes and is confined to M1-positive cells bearing Fc receptors: M1 cytotoxicity inhibition by adding aggregated IgG suggests that these cells are responsible for an antibody-dependent cell-mediated mechanism (ADCC). Moreover, when T-enriched fractions were separated in T4, T8 and 5/9 positive subsets, only the first one showed a significant cytotoxicity: T4 positive cells might act as cytotoxic T cells or might be involved in delayed type hypersensitivity (DTH) reactions. Cytotoxic T lymphocytes in HBsAg-positive CAH with HBcAg in liver tissue are confined in T8 positive subset, while helper/inducer T cells (T4 positive or 5/9 positive) seem to play an important role only in the induction of cell-mediated injury against hepatocytes. The inhibition of T cell-cytotoxicity by preincubating liver cells with monoclonal antibody (Mab) anti-HLA AB and not with Mab anti-HLA DR or aggregated IgG supports the involvement of the class I major histocompatibility complex (MHC) expressed on the hepatocyte surface.