An imbalance in the T-helper phenotypes displayed by senescent CD4+CD28null T cells is associated with erosive arthritis (rhupus syndrome) in systemic lupus erythematosus

OBJECTIVE

The objective was to assess the proportion of Th1, Th2 and Th17 phenotypes in senescent CD4⁺CD28^null cells from patients with systemic lupus erythematosus (SLE) and its association with the pattern of joint involvement.

METHODS

This cross-sectional study was performed in SLE patients with erosive arthritis (rhupus) or nondeforming, nonerosive arthritis. Total CD4⁺CD28^null cells as well as the proportion of these cells expressing T-bet, GATA3 or RORγt were analyzed by color-flow cytometry. Serum osteopontin levels were measured by ELISA.

RESULTS

Eighteen SLE patients (nine with rhupus and nine with nonerosive arthritis) were studied. The percentage of CD4⁺CD28^null/CD4⁺ cells (17.7%, 10.3-25.0% versus 9.4%, 8.1-22.4%; P = 0.386) as well as the osteopontin levels (5800, 5,134-5995 pg/ml versus 5578, 5171-5717 pg/ml; P > 0.05) were similar in both groups. A higher percentage of CD4⁺CD28^nullT-bet⁺ cells (42.8%, 33.5-53.4% versus 30.0%, 23.3-34.2%) but a lower percentage of CD4⁺CD28^nullGATA3⁺ cells (3.1%, 1.7-5.6% versus 6.2%, 2.6-18.4%) was observed in patients with rhupus than in their counterparts ( P = 0.016). The frequency of CD4⁺CD28^nullRORγt⁺ cells was similar between groups.

CONCLUSIONS

In patients with rhupus, senescent CD4⁺CD28^null cells are preferentially polarized to a Th1 phenotype, whereas this is partial towards Th2 in lupus patients with a nonerosive arthritis pattern.

Enhanced survival from CLP-induced sepsis following late administration of low doses of anti-IFNγ F(ab')2 antibody fragments

OBJECTIVE

To assess the impact of different doses of anti-interferon gamma (anti-IFNγ) F(ab')2 fragments, administered prophylactically, on survival and on serum concentration of cytokines in a murine model of sepsis induced by cecal ligation and puncture (CLP). We further explore the impact of therapeutic administration of the most protective dose on survival.

SUBJECTS AND TREATMENT

Balb/c mice were prophylactically treated by the intraperitoneal route with anti-IFNγ initiated 2 h before CLP and every 24 h for a total of five times in each of the following doses: 0.01, 0.1, or 1 mg/kg. Sham and control groups received sterile saline solution in a similar scheme.

METHODS

Serum tumor necrosis factor (TNF), interleukin (IL)-1β, IL-6, IL-10 and IFNγ were measured at 3, 24 and 48 h after CLP by ELISA. Survival curves were compared using a Mantel-Haenzel method.

RESULTS

Significant prophylactic protection was found only with 0.01 mg/kg, in association with regulation of IL-1β and IL-10 concentrations. As therapy, anti-IFNγ fragments were protective only when initiated 24 h after CLP.

CONCLUSIONS

Delicate modulation of IFNγ at the correct timing, even when the septic process has begun, is an exciting alternative to explore in the treatment of sepsis.

LPS pretreatment by the oral route protects against sepsis induced by cecal ligation and puncture. Regulation of proinflammatory response and IgM anti-LPS antibody production as associated mechanisms

OBJECTIVE

To explore the efficacy of prophylactic oral lipopolysaccharide (LPS) in sepsis induced by cecal ligation and puncture (CLP).

MATERIAL

Male Balb/c mice. LPS serotype O55: B5

TREATMENT

Mice were treated every 4 days for a total of 5 times with 50 mug of LPS by intraperitoneal (IP) or oral (O) routes. Treatment was stopped one week prior to CLP. Control (C) groups received the vehicle orally, and sham (S) groups were used as reference.

METHODS

Histopathology was performed to determine inflammation in liver and lung. Serum cytokines were measured by ELISA, and TNFalpha tissue expression by RTPCR. Antibodies against LPS were measured by ELISA.

RESULTS

Administration of LPS by the oral route significantly increased survival (p<0.05) of mice in association with a reduction of Kupffer cells in liver, pulmonary edema in lung, shorter or delayed TNFalpha expression in target organs, a trend to decreased IFN gamma and increased IL-10 serum levels, and a notable increase in the production of specific IgM anti-LPS antibodies.

CONCLUSIONS

LPS by oral route protected against CLP. The underlying mechanisms could be the modulation of the proinflammatory response and an increased production of IgM anti-LPS antibodies.

Mechanical deformation inhibits IL-10 and stimulates IL-12 production by mouse calvarial osteoblasts in vitro

The skeleton is continuously remodelled throughout life, a process that is orchestrated by cells of the osteoblast lineage. Remodelling involves a complex network of cell-cell signalling involving systemic hormones, locally produced cytokines, growth factors and the mechanical environment of the cells. Here, we report on the effect of mechanically-induced strain on the synthesis by mouse calvarial osteoblasts in monolayer culture of IL-10 and IL-12, two cytokines that inhibit osteoclast formation in bone marrow cultures; IL-10 also suppresses osteoblast differentiation suggesting a role for both cytokines in bone physiology. A tensile strain was applied to the cells intermittently for 6s, every 90s, for 2-96h. After 2-h culture, supernatants from deformed cells contained significantly less IL-10 than control cultures. In contrast, mechanical deformation had a stimulatory effect on IL-12 synthesis; however, by 48h both had returned to control levels. These data suggest that IL-10 and IL-12 can be added to the growing list of mechanical stress-responsive genes. The down-regulation of IL-10 and stimulation of IL-12 further suggests that the initial response of the cells to mechanical deformation was an osteogenic one.

Simplified method for the detection of apo(a) isoforms

Apolipoprotein a, is a high molecular weight glycoproteic component of Lp(a), a molecule associated with coronary arterial disease. Apo(a) exhibits considerable size heterogeneity due to variable repetitions of the carbohydrate-containing structural unit, termed kringle. There are five different kringle forms and 10 different kringle 4 types. Apo(a) polymorphism and molecular weight depend on the number of copies of kringle 4 type 2. In this paper we describe a modified 3.75% and 6% discontinuous polyacrylamide gel system and Western-blot technique that shortness the assay time and improves the identification of apo(a) isoforms with a theoretical error of less than 1 kringle. The assay uses a standard curve prepared with five different recombinant apo(a) molecules, detected up to 50 ng of protein in Lp(a), showed a maximal resolution of 2 kringles and, with the use of third degree polynominal regression analysis, had an error of 0.01275. The inter-assay coefficient of variation was 1.7, 2, and 1.4 for the 14 K, 18 K, and 22 K phenotypes, whereas the intra-assay coefficient of variation was 0.32%, 0.18%, and 0.17%, respectively. It is possible that this modified method will diminish the number of putative null alleles so far detected in various studies, but most of all, we are certain that it can be of use in epidemiological studies due to its ease of use, speed, low cost, and enhanced number of samples that can be tested.

[Role of tumor necrosis factor alpha in atherosclerosis]

We describe tumour necrosis factor alpha and its role in the development of the atherosclerotic lesion, and detail the effects of this cytokine upon vascular endothelial cells under normal and high risk conditions. We propose that TNF-alpha performs a central role in the progression of the lesion since, once the endothelial cell feedback regulatory mechanisms are altered, there is an increase in the microenvironment TNF-alpha concentration, which together with some of the already well known risk factors, generates an environment that favours and perpetuates the development of the atheromatous lesion.

Apolipoprotein E polymorphism in the Indian and Mestizo populations of Mexico

Apolipoprotein E (APOE) genotypes were determined in 75 Mazatecan Indians and 83 Mexican mestizos. APOE allele and genotype frequencies in Mazatecans and mestizos were similar, with high frequencies of the APOE*3 allele (0.900 and 0.915, respectively) and the E3/3 genotype (0.813 and 0.831, respectively) and an absence in both samples of the APOE*2 allele. Our data are similar to those previously described for Mexican-American and Mayan populations, which show the highest frequency worldwide of the APOE*3 allele and the E3/3 genotype. Mazatecans and mestizos also show a decreased frequency of the APOE*4 allele when compared to other Amerindian groups. The absence of the APOE*2 allele has also been reported in other Amerindian groups such as Mayans and Cayapa, whereas in Caucasians the average frequency of this allele is about 8%. Our data are in agreement with previous reports showing absence of the APOE*2 allele in Native American groups. These findings suggest that the APOE*2 allele was absent in humans from northern Asia who settled in the Arctic and populated the American continent.

Differential effect of estradiol on antibody secretion of murine hybridomas

The need for increased antibody production by hybridomas has been approached by the addition to cell cultures of different growth factors; in vitro addition of estradiol-17beta (E2) to human blood lymphocytes increases the accumulation of plasma-blasts and Ig-secreting cells. Four different murine-murine hybridomas secreting different monoclonal antibodies (MAbs) were treated with E2. Specific antibody concentration was measured by enzyme-linked immunoadsorbent assay (ELISA) in culture supernatants whereas expression of E2-receptor in the hybridoma cells was determined by polymerase chain reaction (PCR). When E2 was added as a growth supplement to alpha-estrogen receptor positive murine-murine hybridomas it enhanced MAb secretion by as much as 255%, in a dose-dependant manner. This effect lasted for as long as the alpha-estrogen receptor was detected in the hybridoma cells, was inhibited by tamoxifen and was not observed in alpha-estrogen receptor negative hybridomas. The synthetic estrogen analogue diethylstilbestrol had no effect. Estradiol-17beta should be added to the list of hybridoma-inducing growth factors.

Collagen degrading activity associated with Mycobacterium species

BACKGROUND

The mechanism of Mycobacterium tuberculosis penetration into tissues is poorly understood but it is reasonable to assume that there is a contribution from proteases capable of disrupting the extracellular matrix of the pulmonary epithelium and the blood vessels. A study was undertaken to identify and characterise collagen degrading activity of M tuberculosis.

METHODS

Culture filtrate protein extract (CFPE) was obtained from reference mycobacterial strains and mycobacteria isolated from patients with tuberculosis. The collagen degrading activity of CFPE was determined according to the method of Johnson-Wint using 3H-type I collagen. The enzyme was identified by the Birkedal-Hansen and Taylor method and its molecular mass determined by SDS-PAGE and Sephacryl S-300 gel filtration chromatography using an electroelution purified enzyme.

RESULTS

CFPE from Mycobacterium tuberculosis strain H37Rv showed collagenolytic activity that was four times higher than that of the avirulent strain H37Ra. The 75 kDa enzyme responsible was divalent cation dependent. Other mycobacterial species and those isolated from patients with tuberculosis also had collagen degrading activity.

CONCLUSIONS

Mycobacterium species possess a metalloprotease with collagen degrading activity. The highest enzymatic activity was found in the virulent reference strain H37Rv.

Secretion of IFN-gamma by bovine peripheral blood mononuclear cells stimulated with Mycobacterium bovis protein fractions obtained by isoelectric-focusing

Due to the complexity and variety of biological effects found in Mycobacterium bovis (M. bovis) proteins analyzed solely on a molecular weight (MW) basis, we approached the purification of M. bovis proteins through their isoelectric point (pI). Twenty M. bovis culture filtrate protein extract (CFPE) isoelectric focused (IEF) protein fractions, confined between pI3 and 10, were isolated. The MW of the major proteins isolated in the various fractions correlated with protein already reported 14-, 18-, 20-, 25-, 31-, 38-, 45-, 64-, 67- and 70 kDa by SDS-PAGE. Since several different pI fractions showed proteins of the same MW we tested the ability of all IEF fractions to stimulate interferon-gamma (IFN-gamma) production by peripheral blood mononuclear cells (PBMC) isolated from cattle with well defined M. bovis tuberculosis (TB) infection. In animals with few lesions IFN-gamma inductive IEF fractions were in the acid range. As the number of lesions increased, neutral fractions were also inductive. Some fractions with relatively few proteins induced as much IFN-gamma production as others with abundant proteins. None of the 20 IEF fractions enhanced IFN-gamma production by anergic cells. We conclude that IFN-gamma production in diseased animals is induced mainly by acidic mycobacterial proteins and that the response towards these proteins is enhanced as the disease progresses, what coincides with higher PPD reactivity. However, the IFN-gamma production in anergic status was severely affected. We found that this cytokine production is spontaneous and antigen-independent.

Identification of major glycoconjugates from Mycobacterium bovis culture filtrate by biotin-hydrazide labeling

To identify Mycobacterium bovis glycoproteins, carbohydrates present in a delipidized M. bovis culture filtrate protein extract were biotin-hydrazide labeled. 11 carbohydrate-containing protein with a molecular weight of 15-, 19-, 25-, 32-, 35-, 39-, 42-, 48-, 52-, 58-, and 62-kDa were detected. The 52- and 32-kDa protein were deglycosylated by endoglycosidase-F.

[Phenotype and reactivity of T-lymphocytes isolated from atheromatous plaque. Knowledge obtained from a transplant case]

The primary immunologic hypothesis assumes that the initial damage in atherosclerotic lesions is mediated by T lymphocytes reactive to heat shock proteins, lipoproteins, bacteria, virus or even donor MHC antigens. A frequent cause of heart transplant failure is the de novo formation of atheromatous lesions in the vessels of the transplanted organ despite their absence in the donor, thus suggesting that new lesions are secondary to a cellular immune response by the receptor. In this study we determined the phenotype and the reactivity of T cells from peripheral blood and from endomyocardial and atherectomy biopsies obtained from the same immunosuppressed patient who underwent a heart transplant in 1989. A panel of homozygous HLA-typed, Epstein-Barr virus transformed B lymphocytes were used as stimulators in functional assays. Our results showed an important increase in the percentage of CD4+ cells in the atheromatous plaque as well as in the endomyocardium, and a considerable amount of TCR sigma+ lymphocytes in the atheromatous plaque. A considerable loss of alloreactivity to HLA antigens was also observed. These results suggest that although there are adequate conditions to mount a cellular immune response a state of cellular anergy exists towards HLA antigens probably as result of prolonged immunosuppressive therapy. The presence of obstructive lesions in this particular patient don't seem to be secondary to HLA alloreactivity but could be secondary to a switch in the cellular immune response as a consequence of chronic exposure to some donor antigen, thus explaining the increased proportion of TCR sigma+T lymphocytes.

Endothelin mediation of insulin and glucose-induced changes in vascular contractility

Although the prevalence of hypertension in diabetic patients is high and many factors participate, hyperinsulinemia cannot be discarded as a contributing factor. Insulin could act directly on smooth muscle altering intracellular calcium levels that mediate contraction and glucose transport or could induce the secretion of endothelin by the endothelial cells lining the vessels. The aim of the present report was to study the effect of different glucose and insulin concentrations on rat vascular smooth-muscle contractile characteristics and to determine whether insulin effects are mediated by endothelin. Femoral arteries obtained from Wistar rats were placed in an in vitro chamber and superfused with different glucose and/or insulin solutions. The contractile response to KCl 80 mmol/L, measured by the force generated, showed a significant decrease with high extracellular glucose concentrations (11 mmol/L). Insulin caused a dose-dependent increase in arterial contraction induced by KCl. This increase was significant when arteries were stimulated with 80 mmol/L KCl in the presence of 5.5 mmol/L glucose, but when 40 mmol/L KCl was used, an increase was observed with both 5.5 and 11 mmol/L glucose. The insulin-induced contraction was significantly reduced in the presence of hyperimmune anti-endothelin serum and in the presence of endothelin receptor ET(A) and ET(B) antagonists PD 151,242 and BQ-788, respectively. These results suggest that hyperinsulinemia and hyperglycemia may contribute to hypertension in diabetes and that responses to insulin are mediated partially by endothelin, thus explaining why non-insulin-dependent diabetes mellitus patients show an increase in arterial pressure before the onset of nephropathy.

Effects of mebendazole on protein biosynthesis and secretion in human-derived fibroblast cultures

Previous results of our group revealed that mebendazole, a broad spectrum anthelmintic drug with antimicrotubular properties, used for the treatment of liver cirrhosis, decreased total collagen content and biosynthesis in liver upon treatment. In the present study, we have evaluated the effects of mebendazole (5-50 micrograms/mL) on protein synthesis, secretion, and deposition in human-derived fibroblast cultures. The results showed a decrease in cell viability (18.5 +/- 0.9%) at 50 micrograms/mL. [3H]Thymidine incorporation diminished gradually with increasing mebendazole concentrations, reaching a plateau (53.67%) between 30 and 50 micrograms/mL. In late logarithmic phase cultures, the drug caused a decrease of [3H]proline incorporation (43.10%) and collagen biosynthesis (58.61%) in the extracellular matrix. This correlated with an increase in radioactivity in total proteins (51.28%) of the intracellular fraction. Similar results were obtained when mebendazole was assayed in post-confluent fibroblast cultures. The electrophoretic patterns of the extracellular matrix showed a decrease of radioactive collagenous components (alpha chains and beta dimers). By contrast, in the intracellular fraction an increase of radioactive collagen precursors (pro alpha chains) was observed. Immunofluorescence studies and immunotransfer analysis, using polyclonal anti-type I collagen antibodies, revealed an accumulation of intracellular collagen which included: collagen pro alpha chains, alpha chains, and low molecular weight peptides. The results obtained suggest that mebendazole interferes with the transcellular mobilization of proteins, resulting in a decrease of secretion and deposition of extracellular matrix proteins, and an accumulation of intracellular collagenous components. The intracellular accumulation of newly synthesized proteins could cause a feedback regulation in fibroblast cultures.

Isolation of a 32 kDa Mycobacterium tuberculosis protein by lectin affinity chromatography

A 32 kDa antigen from delipidated M. tuberculosis H37Rv culture filtrate protein extract (CFPE) was purified by affinity chromatography on immobilized Lens culinaris lectin and electroelution. This antigen represents 0.4% of the total CFPE carbohydrate content and possesses galactose, xylose, mannose and GlcNAc (5:2:3:1 mol. ratio). A monoclonal antibody against the purified antigen reacted with the 32 kDa as well as a 30 kDa antigen in H37Rv CFPE, thus suggesting that both antigens represent closely related allelomorphic forms of the same antigen.

[Efficiency of an ELISA using complete and delipidated protein extract from Mycobacterium tuberculosis H37Rv strain as a serological test for ruling out pulmonary tuberculosis]

We present the results of an enzyme-linked immunosorbent assay that detects serum antibodies to M. tuberculosis antigens. The patients sera were tested with two different antigens, one a M. tuberculosis H37Rv culture filtrate protein extract precipitated with ammonium sulfate (CFPE), and the second, a delipidized CFPE (CFPE-d). The results obtained with 52 clearly defined TBP patients was 0.50 +/- 0.16 (CFPE) and 0.38 +/- 0.11 (CFPE-d). We also tested 165 sera from patients hospitalized at the INER with a diagnosis of non-tuberculous pulmonary disease. In this patients the assay revealed 153 negative sera (CFPE = 0.053 +/- 0.01; CFPE-d 0 0.050 +/- 0.004) and 12 positive sera. Nine of these patients (CFPE = 0.38 +/- 0.08; CFPE-d = 0.32 +/- 0.09) had mycobacterias and the results of the remaining three were considered as false positive. TBP was excluded in all the 153 negative patients. The elimination of lipids in the CFPE did not alter the assay since the differences between CFPE and CFPE-d did not reach statistical significance. In non-tuberculous individuals the reactivity with mycobacterial lipids was poor and didn't induce false positive results. The assay we report can be useful in those patients with pulmonary disease where TBP has to be considered.