Autoimmunity to Polymorphonuclears: Functional Consequences of the Binding of Antibodies to Membrane and Cytoplasmic Target Antigens of Polymorphonuclear Leukocytes

Antineutrophil autoantibodies reacting with cytoplasmic antigens are associated with various types of vasculitides, whereas antibodies reacting with neutrophil membrane antigens are mostly related to autoimmune neutropenias. The aim of this study was the investigation of the effect of monoclonal antibodies (MoAbs) reacting with surface and cytoplasmic antigens of polymorphonuclear leukocytes (PMN) known to be targets for autoantibodies in human diseases. Blood of healthy volunteers was tested for several phagocytic functions in the presence of MoAbs against surface (CD16, GD11b, CD18, NB1) and cytoplasmic (proteinase 3; PR3) molecules. Candidacidal activity was significantly inhibited in the presence of all MoAbs but isotypic control. Phagocytic activity was inhibited by anti-CD11b and/or anti-CD18 MoAbs. Zymosan-induced chemiluminescence was reduced by MoAbs anti-CD16, CD18, and NB1, enhanced by anti-PR3 MoAb, and less enhanced by anti-CD11b. In conclusion, antimembrane antibodies diminished phagocytic functions at multiple steps; in contrast, anticytoplasmic MoAb promoted activation of oxidative burst in addition to impairment of microbicidal activity. This fact may be related to different pathogenic aspects of diseases associated with antimembrane and anticytoplasmic antibodies.     

Synthesis and characterization of new siloxane-modified addition polyimides

A new series of polyimides was synthesized by addition polymerization of 4,4′-(bismaleimido)-diphenylmethane, 1,4-piperazine and an amino-terminated polydimethylsiloxane. The synthesis was carried out in m-cresol solution following a two-step procedure. Copolymers containing 15 and 20 wt.-% of the polydimethylsiloxane elastomer were prepared, together with the unmodified base copolymer. Infrared spectroscopy, ¹³C and ¹H NMR, thermal and thermogravimetric analyses were used to characterize the copolymers. The DSC curves of all the samples showed an exotherm in the temperature range 230–280°C, attributable to curing and addition reactions involving the chain-end groups. Different glass transition temperatures (T_g) were observed, depending on the elastomer content. Thermogravimetric analysis indicated that no significant changes occur in the thermal stability of rubber-modified copolymers.     

Clinical variability in mucolipidosis III (pseudo-Hurler polydystrophy)

Mucolipidosis III (MLIII) is caused by a deficiency of UDP-N-acetylglucosamine:lysosomal enzyme N-acetylglucosamine 1-phosphotransferase (phosphotransferase) activity, an enzyme responsible for the formation of the recognition marker on most lysosomal enzymes. The consequences of this defect are impairment of many lysosomal catabolic processes. A deficiency of phosphotransferase activity causes two phenotypically different diseases: mucolipidosis II and a rare form, mucolipidosis III (pseudo-Hurler polydystrophy). The purpose of this article is to report three patients with ML III, presenting quite different clinical courses: Patient 1 is a 13-year-old girl in whom the only symptoms of ML III were joint stiffness of the hands. Patients 2 and 3 are sibs: a 5-year-old boy with a severe form of ML III and his 2-year-old sister, who is less affected than her brother at the same age. A comparison of biochemical results and the clinical picture of our patients with cases in the literature is presented.     

Nutritional effects on host response to lung infections with mucoid Pseudomonas aeruginosa in mice

In cystic fibrosis, a recessive genetic disease caused by defects in the cystic fibrosis conductance regulator (CFTR), the main cause of death is lung infection and inflammation. Nutritional deficits have been proposed to contribute to the excessive host inflammatory response in both humans and Cftr-knockout mice. Cftr-knockout mice and gut-corrected Cftr-knockout mice expressing human CFTR primarily in the gut were challenged with Pseudomonas aeruginosa-laden agarose beads; they responded similarly with respect to bronchoalveolar lavage cell counts and levels of the acute-phase cytokines tumor necrosis factor alpha, interleukin-1beta (IL-1beta), and IL-6. Wild-type mice fed the liquid diet used to prevent intestinal obstruction in Cftr-knockout mice had inflammatory responses to P. aeruginosa-laden agarose beads similar to those of wild-type mice fed an enriched solid diet, so dietary effects are unlikely to account for differences between wild-type mice and mice with cystic fibrosis. Finally, since cystic fibrosis patients and Cftr-knockout mice have an imbalance in fatty acids (significantly lower-than-normal levels of docosahexaenoic acid), the effects of specific supplementation with docosahexaenoic acid of wild-type and Cftr-knockout mice on their inflammatory responses to P. aeruginosa-laden agarose beads were tested. There were no significant differences (P = 0.35) in cumulative survival rates between Cftr-knockout mice and wild-type mice provided with either the liquid diet Peptamen or Peptamen containing docosahexaenoic acid. In conclusion, diet and docosahexaenoic acid imbalances alone are unlikely to explain the differences in the host response to lung infections with mucoid P. aeruginosa between mice with cystic fibrosis and their wild-type counterparts.     

Molecular interactions of fission yeast Skp1 and its role in the DNA damage checkpoint

Skp1 is a central component of the E3 ubiquitin ligase SCF (Skp1-Cullin-1-F-box). It forms an adapter bridge between Cullin-1 and the substrate-determining component, the F-box protein. In order to establish the role of Skp1, a temperature sensitive (ts) screen was carried out using mutagenic PCR (polymerase chain reaction) and 9 independent ts mutants were isolated. Mapping the mutated residues on the 3-D structure of human Skp1 suggested that the mutants would be compromised in binding to F-box proteins but not Cullin-1 (Pcu1). In order to assess the binding properties of ts Skp1, 12 F-box proteins and Pcu1 were epitope-tagged, and co-immunoprecipitation performed. This systematic analysis showed that ts Skp1 retains binding to Pcu1. However, binding to three specific F-box proteins, essential Pof1, Pof3 involved in maintaining genome integrity, and nonessential Pof10, was reduced. skp1ts cells exhibit a G2 cell cycle delay, which is attributable to activation of the DNA damage checkpoint. Intriguingly, contrary to pof3 mutants, in which this checkpoint is required for survival, checkpoint abrogation in skp1(ts) suppresses a G2 delay and furthermore almost rescues the ts phenotype. The activation mechanism of the DNA damage checkpoint therefore differs between pof3Delta and skp1(ts), implicating a novel role for Skp1 in the checkpoint-signalling cascade.     

A survey of bacterial diversity in ticks,lice and fleas from Australia

We isolated bacteria from ticks, lice and fleas. Partial small subunit rRNA sequences were obtained for each isolate and the closest matches in the FastA database were determined. These bacteria were mostly Gram-positive (Firmicutes), although representatives from the Proteobacteria (alpha, beta, gamma subdivisions) and CFB group were also isolated. Most of the isolates we found were from genera that were present in most of the ectoparasites studied, but a few genera were restricted to one species of ectoparasite. The most commonly isolated genera were Stenotrophomonas, Staphylococcus, Pseudomonas, Acinetobacter and Bacillus. Species of Bacillus and Proteus, which have biopesticide potential, were found in some of these ectoparasites. Overall, the communities of bacteria were similar to those found in other studies of parasitic arthropods.     

Dopamine, serotonin and noradrenaline changes in the striatum of C57BL mice following myelin oligodendrocyte glycoprotein (MOG) 35-55 and complete Freund adjuvant (CFA) administration.

Many data suggest involvement of inflammation in neurodegeneration. However, the exact mechanisms of this cooperation are poorly understood. We have previously shown that induction of inflammatory reaction, both before and after injury of the striatum, affects regeneration of dopaminergic neurons. In the present research we studied the role of inflammatory reaction in non-injured striatum. We used myelin oligodendrocyte glycoprotein (MOG) 35-55 in complete Freund's adjuvant (CFA) to elicit experimental autoimmune encephalomyelitis (EAE) mice model. As determined by HPLC, striatal dopamine (DA) and serotonin levels in mice treated with either MOG 35-55 in CFA or CFA alone were significantly higher compared to vehicle-treated controls on 13th day after induction. The ratio of homovanilic acid/dopamine (HVA/DA) and 3, 4 dihydroxyphenylacetic acid/dopamine (DOPAC/DA) were significantly lower in the MOG and CFA groups on 13th day, indicating decreased DA metabolism. Noradrenaline (NA) concentration did not differ between groups. Moreover, the striatal mRNA IL-1beta and TNF-alpha levels were elevated during induction phase of EAE in both groups, as determined by RT-PCR. Our data indicate regulatory connection between dopaminergic and immune systems.     

Virus replication and evolution drive the kinetics and specificity of SIV-specific cytotoxic T lymphocytes

Summary: SIV (simian immunodeficiency virus) infection of cynomolgus macaques provides an excellent model for investigating the basis of protective immunity against HIV (human immunodeficiency virus). We explored the protective role of cytotoxic T lymphocytes (CTL) against the pathogenic molecular clone SIVmac-J5. Vaccine-induced CTL precursors (CTLp) against Env, Gag or Nef did not protect macaques against intravenous challenge. However, detection of Rev-specific CTLp in infected macaques was associated with effective virus containment. Furthermore, CTL against an immunodominant Gag/p26 epitope (amino acids 242–250) resulted in the emergence of a mutant virus that uniformly replaced wild-type virus in the spleen and partially escaped recognition. During primary infection, CTLp detection in blood coincided with decreasing viremia. After 12 months, two outcomes emerged. In one group of macaques, persistent viremia was associated with high viral load in lymphoid organs and declining CD4⁺ T-cell counts. CTLp were maintained in asymptomatic macaques, but declined in the symptomatic phase of infection. In a second group, loss of detectable viremia was associated with low-level virus reservoirs in lymphoid organs, asymptomatic status and maintained CD4⁺ T-cell counts. CTLp peaked in the first 4 months of infection and subsequently declined in this group. These studies provide insights into the complex interplay between virus replication and host immunity.     

Nonmyeloablative stem cell transplantation is an effective therapy for refractory or relapsed hodgkin lymphoma: results of a spanish prospective cooperative protocol.

We report the results of reduced-intensity conditioning allogeneic stem cell transplantation (allo-RIC) in patients with advanced Hodgkin lymphoma (HL). Forty patients with relapsed or refractory HL were homogeneously treated with an RIC protocol (fludarabine 150 mg/m(2) intravenously plus melphalan 140 mg/m(2) intravenously) and cyclosporin A and methotrexate as graft-versus-host disease (GVHD) prophylaxis. Twenty-one patients (53%) had received >2 lines of chemotherapy, 23 patients (58%) had received radiotherapy, and 29 patients (73%) had experienced treatment failure with a previous autologous stem cell transplantation. Twenty patients (50%) were allografted in resistant relapse, and 38 patients received hematopoietic cells from an HLA-identical sibling. Five patients (12%) died from early transplant-related mortality (before day +100 after allo-RIC). One-year transplant-related mortality was 25%. Acute GVHD developed in 18 patients (45%). Chronic GVHD developed in 17 (45%) of the 31 evaluable patients. The response rate 3 months after the allo-RIC was 67% (21 [52%] complete remissions and 6 [15%] partial remissions). Eleven patients received donor lymphocyte infusions (DLIs) for disease relapse. The response rate after DLI was 54% (3 complete remissions and 3 partial remissions). Overall survival (OS) and progression-free survival (PFS) were 48% +/- 10% and 32% +/- 10% at 2 years, respectively. Refractoriness to chemotherapy was the only adverse prognostic factor for both OS (63% +/- 12% versus 35% +/- 13%; P = .05) and PFS (55% +/- 16% versus 10% +/- 9%; P = .006). For patients with failure of a prior autologous hematopoietic stem cell transplantation, results were especially good for those who experienced late relapses (>/=12 months: 2-year OS and PFS were 75% +/- 16% and 70% +/- 18%, respectively). These data suggest that allo-RIC is feasible in heavily pretreated HL patients and has an acceptable early transplant-related mortality. Results are better in patients allografted in sensitive disease. Both responses observed after the development of GVHD and DLI may suggest a graft-versus-HL effect. Allo-RIC has to be considered an effective therapeutic approach for patients who have had treatment failure with a previous autologous hematopoietic stem cell transplantation.