Citations

ABSTRACT Productive replication of human immunodeficiency virus type 1 (HIV-1) occurs efficiently only in humans. The posttranscriptional stages of the HIV-1 life cycle proceed poorly in mouse cells, with a resulting defect in viral assembly and release. Previous work has shown that the presence of human chromosome 2 increases HIV-1 production in mouse cells. Recent studies have shown that human chromosome region maintenance 1 (hCRM1) stimulates Gag release from rodent cells. Here we report that expressions of hCRM1 in murine cells resulted in marked increases in the production of infectious HIV-1 and feline immunodeficiency virus (FIV). HIV-1 production was also increased by hSRp40, and a combination of hCRM1 and hSRp40 resulted in a more-than-additive effect on HIV-1 release. In contrast, the overexpression of mouse CRM1 (mCRM1) minimally affected HIV-1 and FIV production and did not antagonize hCRM1. In the presence of hCRM1 there were large increases in the amounts of released capsid, which paralleled the increases in the infectious titers. Consistent with this finding, the ratios of unspliced to spliced HIV-1 mRNAs in mouse cells expressing hCRM1 and SRp40 became similar to those of human cells. Furthermore, imaging of intron-containing FIV RNA showed that hCRM1 increased RNA export to the cytoplasm.By testing chimeras between mCRM1 and hCRM1 and comparing those sequences to feline CRM1, we mapped the functional domain to HEAT (Huntingtin, elongation factor 3, protein phosphatase 2A, and the yeast kinase TOR1) repeats 4A to 9A and a triple point mutant in repeat 9A, which showed a loss of function. Structural analysis suggested that this region of hCRM1 may serve as a binding site for viral or cellular factors to facilitate lentiviral RNA nuclear export.

Abstract Systemic lupus erythematosus (SLE) is a chronic, multiorgan inflammatory autoimmune disorder associated with high levels of circulating autoantibodies and immune complexes. We report that passive transfer of human SLE sera into mice expressing the uniquely human FcγRIIA and FcγRIIIB on neutrophils induces lupus nephritis and in some cases arthritis only when the mice additionally lack the CD18 integrin, Mac-1. The prevailing view is that Mac-1 on macrophages is responsible for immune complex clearance. However, disease permitted by the absence of Mac-1 is not related to enhanced renal immune complex deposition or in situ C1q/C3 complement activation and proceeds even in the absence of macrophages. Instead, disease is associated with increased FcγRIIA-induced neutrophil accumulation that is enabled by Mac-1 deficiency. Intravital microscopy in the cremasteric vasculature reveals that Mac-1 mitigates FcγRIIA-dependent neutrophil recruitment in response to deposited immune complexes. Our results provide direct evidence that human SLE immune complexes are pathogenic, demonstrate that neutrophils are primary mediators of end organ damage in a novel humanized lupus mouse model, and identify Mac-1 regulation of FcγRIIA-mediated neutrophil recruitment as a key step in development of target organ damage.

AbstractImmunomodulators are effective in controlling hematologic malignancy by initiating or reactivating host antitumor immunity to otherwise poorly immunogenic and immune suppressive cancers. We aimed to boost antitumor immunity in B-cell lymphoma by developing a tumor cell vaccine incorporating α-galactosylceramide (α-GalCer) that targets the immune adjuvant properties of NKT cells. In the Eμ-myc transgenic mouse model, single therapeutic vaccination of irradiated, α-GalCer–loaded autologous tumor cells was sufficient to significantly inhibit growth of established tumors and prolong survival. Vaccine-induced antilymphoma immunity required NKT cells, NK cells, and CD8 T cells, and early IL-12–dependent production of IFN-γ. CD4 T cells, gamma/delta T cells, and IL-18 were not critical. Vaccine treatment induced a large systemic spike of IFN-γ and transient peripheral expansion of both NKT cells and NK cells, the major sources of IFN-γ. Furthermore, this vaccine approach was assessed in several other hematopoietic tumor models and was also therapeutically effective against AML-ETO9a acute myeloid leukemia. Replacing α-GalCer with β-mannosylceramide resulted in prolonged protection against Eμ-myc lymphoma. Overall, our results demonstrate a potent immune adjuvant effect of NKT cell ligands in therapeutic anticancer vaccination against oncogene-driven lymphomas, and this work supports clinical investigation of NKT cell–based immunotherapy in patients with hematologic malignancies.

Osteomalacia has multiple aetiologies including the least common, tumour-induced osteomalacia (TIO). Recently, most cases of TIO have been confirmed to be due to phosphaturic mesenchymal tumour of mixed connective tissue type (PMTMCT). Most cases of TIO are the result of production of the fibroblast growth factor-23 (FGF-23) by the tumour. The authors recently showed reverse transcriptase PCR (RT-PCR) for FGF-23 to be valuable in the diagnosis of PMTMCT. However, the authors also noted FGF-23 expression in some cases of aneurysmal bone cyst (ABC) and chondromyxoid fibroma (CMF). For the present study, the authors studied FGF-23 expression by RT-PCR in 19 cases of ABC and eight cases of CMF, all with typical clinical and radiographic features and without evidence of TIO. Seven of 16 (44%) ABC and two of seven (29%) CMF were positive for FGF-23. These results confirm that ABC and CMF not uncommonly express FGF-23. These results strongly suggest caution and careful integration with all other clinical and radiographic data in the use of FGF-23 RT-PCR for the diagnosis of PMTMCT.

Background Higher mortality for patients with aneurysmal subarachnoid haemorrhage has been reported. Aims In families with intracranial aneurysms, we sought to determine whether mortality among subjects with intracranial aneurysm (affected) was higher and related to rupture, compared with unaffected family members. Methods Subjects enrolled in the Familial Intracranial Aneurysm protocol were contacted yearly and their status was obtained. If reported to be deceased, the cause of death was verified by available records. A Cox proportional hazards model was utilized to compare mortality rates. Results Of the 2794 subjects, 1073 were affected and 1721 were unaffected. There were 8525 person-years of follow-up (mean 3·05 ± 1·73 years) and 85 deaths. Age at study entry for the affected (58·4 ±11·9 years) was significantly older ( P < 0·0001) than for the unaffected (52·2 ± 16·1). After adjusting for age, the overall mortality rate for the affected subjects was not significantly different from that for the unaffected (Rate Ratio [RR] 1·26, 95% confidence interval 0·82–1·93, P = 0·292). There was a strong effect modification due to age. The mortality rate ratio of the affected to the unaffected who were ≤60 years of age was RR = 3·48 (95% confidence interval: 1·59–7·63, P = 0·002), the rate for the affected subjects who were ≥60 was less than the rate for the unaffected (RR = 0·69, 95% confidence interval: 0·404–1·19, P = 0·178). The affected who had ruptures had 2·62 times the mortality rate as those without ruptures (95% confidence interval 1·43–4·80, P = 0·002). Conclusion The overall mortality was similar for the affected and unaffected subjects in this cohort. Among the affected only, those with ruptured intracranial aneurysm had a higher mortality rate than those without ruptured.