Humoral autoimmunity to basement membrane antigens is regulated in C57BL/6 and MRL/MpJ mice transgenic for anti-laminin Ig receptors

Basement membrane proteins are targeted in organ-limited and systemic autoimmune nephritis, yet little is known about the origin or regulation of immunity to these complex extracellular matrices. We used mice transgenic for a nephrotropic systemic lupus erythematosus (SLE) Ig H chain to test the hypothesis that humoral immunity to basement membrane is actively regulated. The LamH-Cmu Ig H chain transgene combines with diverse L chains to produce nephrotropic Ig reactive with murine laminin alpha1. To determine the fate of transgene-bearing B cells in vivo, transgenic mice were outcrossed onto nonautoimmune B6 and SLE-prone MRL backgrounds and exposed to potent mitogen or Ag in adjuvant. In this work we demonstrate that transgenic autoantibodies are absent in serum from M6 and M29 lineage transgenic mice and transgenic B cells hypoproliferate and fail to increase Ig production upon exposure to endotoxin or when subjected to B cell receptor cross-linking. Administration of LPS or immunization with autologous or heterologous laminin, maneuvers that induce nonoverlapping endogenous anti-laminin IgG responses, fails to induce a transgenic anti-laminin response. The marked reduction in splenic B cell number suggests that selected LamH-Cmu H chain and endogenous L chain combinations generate autospecificities that lead to B cell deletion. It thus appears that SLE-like anti-laminin B cells have access to and engage a tolerizing self-Ag in vivo. Failure to induce autoimmunity by global perturbations in immune regulation introduced by the MRL autoimmune background and exposure to potent environmental challenge suggests that humoral immunity to nephritogenic basement membrane epitopes targeted in systemic autoimmunity is tightly regulated.     

Disordered Sleep and Myopia Risk among Chinese Children

Purpose

Disordered sleep and myopia are increasingly prevalent among Chinese children. Similar pathways may be involved in regulation of both sleep cycles and eye growth. We therefore sought to examine the association between disordered sleep and myopia in this group.

Methods

Urban primary school children participating in a clinical trial on myopia and outdoor activity underwent automated cycloplegic refraction with subjective refinement. Parents answered questions about children''s sleep duration, sleep disorders (Children''s Sleep Habits Questionnaire [CSHQ]), near work and time spent outdoors.

Results

Among 1970 children, 1902 (96.5%, mean [standard deviation SD] age 9.80 [0.44] years, 53.1% boys) completed refraction and questionnaires. Myopia < = -0.50 Diopters was present in both eyes of 588 (30.9%) children (1329/3804 = 34.9% of eyes) and 1129 children (59.4%) had abnormal CSHQ scores (> 41). In logistic regression models by eye, odds of myopia < = -0.50D increased with worse CSHQ score (Odds Ratio [OR] 1.01 per point, 95% Confidence Interval [CI] [1.001, 1.02], P = 0.014) and more night-time sleep (OR 1.02, 95% CI [1.01, 1.04, P = 0.002], while male sex (OR 0.82, 95% CI [0.70, 0.95], P = 0.008) and time outdoors (OR = 0.97, 95% CI [0.95, 0.99], P = 0.011) were associated with less myopia. The association between sleep duration and myopia was not significant (p = 0.199) for total (night + midday) sleep.

Conclusions

Myopia and disordered sleep were both common in this cohort, but we did not find consistent evidence for an association between the two.

Trial Registration

clinicaltrials.gov NCT00848900     

Lipid and reproductive cycles of bluegills (Lepomis macrochirus) exposed to 35 years of elevated environmental temperatures

1. We studied bluegills to compare how thermal perturbation affected lipid dynamics and reproductive cycles of fish from heated (Pond C) and normothermic (Par Pond) sites.

2. Bodies of bluegills contained over 90%, and gonads and livers 10% of the non-polar lipids.

3.Overall, the percent body lipids of bluegills from the heated pond was twice as high (12.4%) as that of Par Pond bluegills (6.6%).

4. During a prolonged reactor down period, when both ponds were normothermic, body lipids of bluegills from Pond C and Par Pond increased at a rate of approximately 3 and 1% of body mass per week, respectively.

5. Juveniles from Pond C had higher percent stored lipids than did adult males or females.

6. Lipid cycling in Par Pond bluegills was seasonal, whereas Pond C bluegill lipid cycles corresponded to long reactor down periods.     

Alteration of colonial morphology of Acholeplasma laidlawii and Acholeplasma modicum by infection with Mycoplasmatales viruses.

Morphologically aberrant colonies resulted from the infection of Acholeplasma laidlawii with two of its three known viruses and from Acholeplasma modicum cells naturally carrying virus. The patterns of colonial alteration differed between cells infected with the two A. laidlawii viruses. Colonies derived from single cells infected with the bullet-shaped virus MV-L1 (Mycoplasmatales virus-laidlawii-1) had a radial sectoring pattern of intracolonial swellings ("blebs"), whereas cells infected with the tailed icosahedral virus MV-L3 contained bubble-like blebs. Colonies from cellsinfected with the enveloped virus MV-L2 appeared identical to those obrained from uninfected cells. Aberrant colonies contained 10(6) colony-forming units of organisms and 10(6) plaque-forming units of virus serologically identical to the infecting type, indicating that both the virus and host organism were capable of simultaneous replication. Enumeration of virus by means of counting aberrant colonies was 30-fold more sensitive than infectious center assay for MV-L1 and 1.2- to 2-fold higher for MV-L3. Furthermore, blebbed colonies plaquing with a new virus specific to A. modicum. Thus, blebbing in colonies provides a valuable marker for detection of the Mycoplasmatales viruses.     

Color Polymorphism in Spiny Spiders (Gasteracantha fornicata): Testing the Adaptive Significance of a Geographically Clinal Lure

Many sit‐and‐wait predators use conspicuous displays of color to attract prey. These displays sometimes express discrete polymorphisms; however, the adaptive drivers of such variation are not well understood. Here, we explore a previously unknown color polymorphism in the orb‐web spider Gasteracantha fornicata. We discovered that in North Queensland, Australia, female spiders exhibit dorsal bands appearing (to the human observer) either white or yellow and characterized by sigmoidal spectral curves centered on approx. 447 and 496 nm, respectively. Based on sensory drive theory, we hypothesized that morphs may be alternatively favored by the switch in ambient viewing conditions engendered by sunny vs. cloudy skies. We addressed this hypothesis indirectly by studying morph frequencies across a approx. 200 km geographic gradient of solar exposure (a surrogate for cloudiness), and by investigating the phenotypic signature of catch success via a resource stress experiment and in wild spiders. Our data indicate substantial geographic variation in morph frequency, with white morphs dominating at more cloudy northern locations. Rather than a gradual cline, morph frequency inverted mid‐way along this range and was closely fit by a logistic relationship with latitude. Experimentally restricted access to larger prey caused spiders to lose more mass than size and to exhibit less bright dorsal markings. Wild‐sampled spiders from two localities of divergent morph frequency indicated no differences in residual mass, but intriguingly, the white morph was larger and heavier (than the yellow morph) where it was relatively rare. Our data hint at negative frequency dependence, but remain broadly consistent with a sensory drive explanation based on cloudiness, and we suggest these as worthy avenues for closer investigation.     

Potency of a tau fibrillization inhibitor is influenced by its aggregation state

Tau fibrillization is a potential therapeutic target for Alzheimer's and other neurodegenerative diseases. Several small-molecule inhibitors of tau aggregation have been developed for this purpose. One of them, 3,3'-bis(beta-hydroxyethyl)-9-ethyl-5,5'-dimethoxythiacarbocyanine iodide (N744), is a cationic thiacarbocyanine dye that inhibits recombinant tau filament formation when present at submicromolar concentrations. To prepare dosing regimens for testing N744 activity in biological models, its full concentration-effect relationship in the range 0.01-60muM was examined in vitro by electron microscopy and laser light scattering methods. Results revealed that N744 concentration dependence was biphasic, with fibrillization inhibitory activity appearing at submicromolar concentration, but with relief of inhibition and increases in fibrillization apparent above 10muM. Therefore, fibrillization was inhibited 50% only over a narrow concentration range, which was further reduced by filament stabilizing modifications such as tau pseudophosphorylation. N744 inhibitory activity also was paralleled by changes in its aggregation state, with dimer predominating at inhibitory concentrations and large dye aggregates appearing at high concentrations. Ligand dimerization was promoted by the presence of tau protein, which lowered the equilibrium dissociation constant for dimerization more than an order of magnitude relative to controls. The results suggest that ligand aggregation may play an important role in both inhibitory and disinhibitory phases of the concentration-effect curve, and may lead to complex dose-response relationships in model systems.     

A pilot study of IL-2Rα blockade during lymphopenia depletes regulatory T-cells and correlates with enhanced immunity in patients with glioblastoma

Background

Preclinical studies in mice have demonstrated that the prophylactic depletion of immunosuppressive regulatory T-cells (T_Regs) through targeting the high affinity interleukin-2 (IL-2) receptor (IL-2Rα/CD25) can enhance anti-tumor immunotherapy. However, therapeutic approaches are complicated by the inadvertent inhibition of IL-2Rα expressing anti-tumor effector T-cells.

Objective

To determine if changes in the cytokine milieu during lymphopenia may engender differential signaling requirements that would enable unarmed anti-IL-2Rα monoclonal antibody (MAbs) to selectively deplete T_Regs while permitting vaccine-stimulated immune responses.

Methodology

A randomized placebo-controlled pilot study was undertaken to examine the ability of the anti-IL-2Rα MAb daclizumab, given at the time of epidermal growth factor receptor variant III (EGFRvIII) targeted peptide vaccination, to safely and selectively deplete T_Regs in patients with glioblastoma (GBM) treated with lymphodepleting temozolomide (TMZ).

Results and Conclusions

Daclizumab treatment (n = 3) was well-tolerated with no symptoms of autoimmune toxicity and resulted in a significant reduction in the frequency of circulating CD4+Foxp3+ TRegs in comparison to saline controls (n = 3)( p = 0.0464). A significant (p<0.0001) inverse correlation between the frequency of TRegs and the level of EGFRvIII specific humoral responses suggests the depletion of TRegs may be linked to increased vaccine-stimulated humoral immunity. These data suggest this approach deserves further study.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00626015","term_id":"NCT00626015"}}NCT00626015