Corpora amylacea act as containers that remove waste products from the brain.

Corpora amylacea (CA) in the human brain are granular bodies formed by polyglucosan aggregates that amass waste products of different origins. They are generated by astrocytes, mainly during aging and neurodegenerative conditions, and are located predominantly in periventricular and subpial regions. This study shows that CA are released from these regions to the cerebrospinal fluid and are present in the cervical lymph nodes, into which cerebrospinal fluid drains through the meningeal lymphatic system. We also show that CA can be phagocytosed by macrophages. We conclude that CA can act as containers that remove waste products from the brain and may be involved in a mechanism that cleans the brain. Moreover, we postulate that CA may contribute in some autoimmune brain diseases, exporting brain substances that interact with the immune system, and hypothesize that CA may contain brain markers that may aid in the diagnosis of certain brain diseases.

Targeting peptide-enhanced antibody and CD11c+ dendritic cells to inclusion bodies expressing protective antigen against ETEC in mice.

Enterotoxigenic Escherichia coli (ETEC) remains a massive burden in developing countries with increasing morbidity and mortality rates; it is also an important pathogen in the farming industry and is a leading cause of bacterial diarrhea. Our previous study showed that nanometer-sized inclusion bodies (IBs) of the fimbrial adhesin subunit protein (FaeG), mutation heat-stable enterotoxin a (mSTa), heat-labile enterotoxin b (LTb), and STb (nontargeting) fusion protein as an oral vaccine induced both systemic and mucosal immune responses. In this study, to enhance the protective efficacy to ETEC, we used Yersinia enterocolitica adhesive and M-cell-targeting peptides to analyze high-efficiency antigen-specific immune presentation in the gut. Here, we showed that immunization with the IBs of ETEC-FaeG-mSTa-LTb-STb-induced a specific systemic and mucosal immune response in the gut, whereas the combination of both targeting peptides resulted in the highest titer, protective immune response against ETEC. A lymphocyte proliferation assay has shown that the IBs induced immunologic memory. The specific antibody of the targeting groups could effectively neutralize toxins, thereby protecting the cells of the small intestine and reducing the level of cAMP and cGMP, and the groups with double targeting showed the best effect. The most important finding was that the targeting peptides stimulate the T helper (Th) cells through Th17 and Th1 and that Th1 cells dominated the cellular immune response. We found that the targeting peptide could also activate CD11c+ on lymphoid dendritic cells, which processed and presented antigens to T cells through Th1-mediated IFN-γ and IL-12, thereby enhancing the antibody titers. The double-targeting peptide had a better effect on stimulating the immune cells to enhance the antibody titers.-Jiang, X., Xia, S., He, X., Ma, H., Feng, Y., Liu, Z., Wang, W., Tian, M., Chen, H., Peng, F., Wang, L., Zhao, P., Ge, J., Liu, D. Targeting peptide-enhanced antibody and CD11c+ dendritic cells to inclusion bodies expressing protective antigen against ETEC in mice.

Safe haven under constant attack-The Chlamydia-containing vacuole.

Chlamydia belong to the group of obligate intracellular bacteria that reside in a membrane bound vacuole during the entire intracellular phase of their life cycle. This vacuole called inclusion shields the bacteria from adverse influences in the cytosol of the host cell like the destructive machinery of the cell-autonomous defence system. The inclusion thereby prevents the digestion and eradication in specialised compartments of the intact and viable cell called phagolysosomes or autophagolysosomes. It is becoming more and more evident that keeping the inclusion intact also prevents the onset of cell intrinsic cell death programmes that are activated upon damage of the inclusion and direct the cell to destruct itself and the pathogen inside. Chlamydia secrete numerous proteins into the inclusion membrane to protect and stabilise their unique niche inside the host cell. We will focus in this review on the diverse attack strategies of the host aiming at the destruction of the Chlamydia-containing inclusion and will summarise the current knowledge on the protection mechanisms elaborated by the bacteria to maintain the integrity of their replication niche.

B-cell-specific accumulation of inclusion bodies loaded with HLA class II molecules in patients with mucolipidosis II (I-cell disease).

BACKGROUND: I-cell disease is characterized by the presence of vacuole-like inclusions in lymphocytes. However, the nature and clinical significance of these inclusions have seldom been characterized. In this study, the authors tried to elucidate the distribution in different lymphocyte subpopulations, and the histological nature of the inclusions. METHODS: Blood samples from three unrelated patients were analyzed. Lymphocyte subpopulations were separated using monoclonal antibodies conjugated to immunomagnetic beads. Cytochemical studies were performed using FITC-conjugated lectins. The expressions of surface and cytoplasmic class II molecules were analyzed by flow cytometry. RESULTS: Virtually all B cells from the patients contained the inclusions. In contrast, CD4+ T cells, CD8+ T cells, natural killer cells, monocytes, or neutrophils did not contain the inclusions. Both fibroblasts and B cells from I-cell patients were stained intensely by multiple FITC-conjugated lectins with distinct binding profiles. The inclusions of B cells were stained intensely by fluorescence-conjugated antibodies against class II antigens. CONCLUSIONS: Inclusions in I-cell disease reflect the accumulation of HLA class II molecules within B cells. These results suggest a potential role for N-acetylglucosamine-1-phosphotransferase in immune functions. Furthermore, the fact that only B cells contain the inclusions provides a novel diagnostic aid for the diagnosis of I-cell disease.

Histone chaperone HIRA deposits histone H3.3 onto foreign viral DNA and contributes to anti-viral intrinsic immunity.

The HIRA histone chaperone complex deposits histone H3.3 into nucleosomes in a DNA replication- and sequence-independent manner. As herpesvirus genomes enter the nucleus as naked DNA, we asked whether the HIRA chaperone complex affects herpesvirus infection. After infection of primary cells with HSV or CMV, or transient transfection with naked plasmid DNA, HIRA re-localizes to PML bodies, sites of cellular anti-viral activity. HIRA co-localizes with viral genomes, binds to incoming viral and plasmid DNAs and deposits histone H3.3 onto these. Anti-viral interferons (IFN) specifically induce HIRA/PML co-localization at PML nuclear bodies and HIRA recruitment to IFN target genes, although HIRA is not required for IFN-inducible expression of these genes. HIRA is, however, required for suppression of viral gene expression, virus replication and lytic infection and restricts murine CMV replication in vivo. We propose that the HIRA chaperone complex represses incoming naked viral DNAs through chromatinization as part of intrinsic cellular immunity.

Myositis-specific autoantibodies: an important tool to support diagnosis of myositis.

The idiopathic inflammatory myopathies are characterized by muscle weakness, skin disease and internal organ involvement. Autoimmunity is known to have a role in myositis pathogenesis, and myositis-specific autoantibodies, targeting important intracellular proteins, are regarded as key biomarkers aiding in the diagnosis of patients. In recent years, a number of novel myositis autoantibodies including anti-TIF1, anti-NXP2, anti-MDA5, anti-SAE, anti-HMGCR and anti-cN1A have been identified in both adult and juvenile patients. These autoantibodies correlate with distinct clinical manifestations and importantly are found in inclusion body, statin-induced, clinically amyopathic and juvenile groups of myositis patients, previously believed to be mainly autoantibody negative. In this review, we will describe the main myositis-specific and myositis-associated autoantibodies and their frequencies and clinical associations across different ages and ethnic groups. We will also discuss preliminary studies investigating correlations between specific myositis autoantibody titres and clinical markers of disease course, collectively demonstrating the utility of myositis autoantibodies as both diagnostic and prognostic markers of disease.

Production of soluble truncated spike protein of porcine epidemic diarrhea virus from inclusion bodies of Escherichia coli through refolding.

The emergence of highly pathogenic variant porcine epidemic diarrhea virus (PEDV) strains, from 2013 to 2014, in North American and Asian countries have greatly threatened global swine industry. Therefore, development of effective vaccines against PEDV variant strains is urgently needed. Recently, it has been reported that the N-terminal domain (NTD) of S1 domain of PEDV spike protein is responsible for binding to the 5-N-acetylneuraminic acid (Neu5Ac), a possible sugar co-receptor. Therefore, the NTD of S1 domain could be an attractive target for the development of subunit vaccines. In this study, the NTD spanning amino acid residues 25-229 (S25-229) of S1 domain of PEDV variant strain was expressed in Escherichia coli BL21 (DE3) in the form of inclusion bodies (IBs). S25-229 IBs were solubilized in 20 mM sodium acetate (pH 4.5) buffer containing 8 M urea and 1 mM dithiothreitol with 95% yield. Solubilized S25-229 IBs were refolded by 10-fold flash dilution and purified by one-step cation exchange chromatography with >95% purity and 20% yield. The CD spectrum of S25-229 showed the characteristic pattern of alpha helical structure. In an indirect ELISA, purified S25-229 showed strong reactivity with mouse anti-PEDV sera. In addition, immunization of mice with 20 µg of purified S25-229 elicited highly potent serum IgG titers. Finally, mouse antisera against S25-229 showed immune reactivity with native PEDV S protein in an immunofluorescence assay. These results suggest that purified S25-229 may have potential to be used as a subunit vaccine against PEDV variant strains.

Adjuvant-enhanced antibody and cellular responses to inclusion bodies expressing FhSAP2 correlates with protection of mice to Fasciola hepatica.

Fasciola hepatica saposin-like protein-2 (FhSAP2) is a protein differentially expressed in various developmental stages of F. hepatica. Recombinant FhSAP2 has demonstrated the induction of partial protection in mice and rabbits when it is administered subcutaneously (SC) in Freund's adjuvant. Because FhSAP2 is overexpressed in bacteria in the form of inclusion bodies (IBs), we isolated IBs expressing FhSAP2 and tested their immunogenicity when administered SC in mice emulsified in two different adjuvants: QS-21 and Montanide TM ISA720. Animals received three injections containing 20 µg of protein two weeks apart and 4 weeks after the third injection, mice were infected with 10 F. hepatica metacercariae by oral route. The percentages of protection induced by FhSAP2-IBs were estimated to be between 60.0 and 62.5% when compared with adjuvant-vaccinated, infected controls. By determining the levels of IgG1 and IgG2a antibodies and IL-4 and IFNγ cytokines in the serum of experimental animals, it was found that both Th1 and Th2 immune responses were significantly increased in the FhSAP2-IBs vaccinated groups compared with the adjuvant-vaccinated, infected control groups. The adjuvant-vaccinated groups had significantly lower IgG1 to IgG2a ratios and lower IL-4 to IFNγ ratios than the FhSAP2-IBs vaccinated animals, which is indicative of higher levels of Th2 immune responses. Irrespective to the adjuvant used, animals vaccinated with FhSAP2-IBs exhibited significantly higher survival percentage and less liver damage than the adjuvant-control groups. This study suggests that FhSAP2 has potential as vaccine against F. hepatica and that the protection elicited by this molecule could be linked to a mechanism driven by the CD4-Th1 cells.

Guanylate binding proteins enable rapid activation of canonical and noncanonical inflammasomes in Chlamydia-infected macrophages.

Interferon (IFN)-inducible guanylate binding proteins (GBPs) mediate cell-autonomous host resistance to bacterial pathogens and promote inflammasome activation. The prevailing model postulates that these two GBP-controlled activities are directly linked through GBP-dependent vacuolar lysis. It was proposed that the rupture of pathogen-containing vacuoles (PVs) by GBPs destroyed the microbial refuge and simultaneously contaminated the host cell cytosol with microbial activators of inflammasomes. Here, we demonstrate that GBP-mediated host resistance and GBP-mediated inflammatory responses can be uncoupled. We show that PVs formed by the rodent pathogen Chlamydia muridarum, so-called inclusions, remain free of GBPs and that C. muridarum is impervious to GBP-mediated restrictions on bacterial growth. Although GBPs neither bind to C. muridarum inclusions nor restrict C. muridarum growth, we find that GBPs promote inflammasome activation in C. muridarum-infected macrophages. We demonstrate that C. muridarum infections induce GBP-dependent pyroptosis through both caspase-11-dependent noncanonical and caspase-1-dependent canonical inflammasomes. Among canonical inflammasomes, we find that C. muridarum and the human pathogen Chlamydia trachomatis activate not only NLRP3 but also AIM2. Our data show that GBPs support fast-kinetics processing and secretion of interleukin-1ß (IL-1ß) and IL-18 by the NLRP3 inflammasome but are dispensable for the secretion of the same cytokines at later times postinfection. Because IFN-γ fails to induce IL-1ß transcription, GBP-dependent fast-kinetics inflammasome activation can drive the preferential processing of constitutively expressed IL-18 in IFN-γ-primed macrophages in the absence of prior Toll-like receptor stimulation. Together, our results reveal that GBPs control the kinetics of inflammasome activation and thereby shape macrophage responses to Chlamydia infections.

Altered RIG-I/DDX58-mediated innate immunity in dermatomyositis.

We investigated the molecular mechanisms involved in the pathogenesis of three inflammatory myopathies, dermatomyositis (DM), polymyositis (PM) and inclusion body myositis (IBM). We performed microarray experiments(†) using microdissected pathological muscle fibres from 15 patients with these disorders and five controls. Differentially expressed candidate genes were validated by immunohistochemistry on muscle biopsies, and the altered pathways were analysed in human myotube cultures. Up-regulation of genes involved in viral and nucleic acid recognition were found in the three myopathies but not in controls. In DM, retinoic acid-inducible gene 1 (RIG-I, DDX58) and the novel antiviral factor DDX60, which promotes RIG-I-mediated signalling, were significantly up-regulated, followed by IFIH1 (MDA5) and TLR3. Immunohistochemistry confirmed over-expression of RIG-I in pathological muscle fibres in 5/5 DM, 0/5 PM and 0/5 IBM patients, and in 0/5 controls. Stimulation of human myotubes with a ligand of RIG-I produced a significant secretion of interferon-ß (IFNß; p < 0.05) and up-regulation of class I MHC, RIG-I and TLR3 (p < 0.05) by IFNß-dependent and TLR3-independent mechanisms. RIG-I-mediated innate immunity, triggered by a viral or damage signal, plays a significant role in the pathogenesis of DM, but not in that of PM or IBM.

Expression of V(H)-linker-V(L) orientation-dependent single-chain Fv antibody fragment derived from hybridoma 2E6 against aflatoxin B1 in Escherichia coli.

Aflatoxin B1 (AFB1) is a toxic secondary metabolic product, which threatens human and animal health. Antibody is a key factor for immunoassay against toxic stuff like AFB1, and single-chain Fv antibody fragment (scFv) has become a popular format of genetically engineered antibody. In this study, four hybridoma cell lines against AFB1 were obtained, and then scFvs 2E6 derived from hybridoma cell line 2E6 were constructed in different V(H)/V(L) orientations. Subsequently, scFvs 2E6 were expressed in E. coli BL21(DE3) mainly in the form of inclusion body. SDS-PAGE, Western blot and ELISA were employed to characterize scFvs 2E6. The results revealed that the yield of inclusion body of scFvs 2E6 in either V(H)/V(L) orientation was similar; however, only the scFv in V(H)-linker-V(L) orientation showed anti-AFB1 bioactivity after refolding. The present study underscores the importance of choosing optimal V(H)/V(L) orientation for scFv construction, and scFv may be favorable for immunoassays in food industry.

Mechanisms of abnormal lamellar body secretion and the dysfunctional skin barrier in patients with atopic dermatitis.

I review how diverse inherited and acquired abnormalities in epidermal structural and enzymatic proteins converge to produce defective permeability barrier function and antimicrobial defense in patients with atopic dermatitis (AD). Although best known are mutations in filaggrin (FLG), mutations in other member of the fused S-100 family of proteins (ie, hornerin [hrn] and filaggrin 2 [flg-2]); the cornified envelope precursor (ie, SPRR3); mattrin, which is encoded by TMEM79 and regulates the assembly of lamellar bodies; SPINK5, which encodes the serine protease inhibitor lymphoepithelial Kazal-type trypsin inhibitor type 1; and the fatty acid transporter fatty acid transport protein 4 have all been linked to AD. Yet these abnormalities often only predispose to AD; additional acquired stressors that further compromise barrier function, such as psychological stress, low ambient humidity, or high-pH surfactants, often are required to trigger disease. T(H)2 cytokines can also compromise barrier function by downregulating expression of multiple epidermal structural proteins, lipid synthetic enzymes, and antimicrobial peptides. All of these inherited and acquired abnormalities converge on the lamellar body secretory system, producing abnormalities in lipid composition, secretion, and/or extracellular lamellar membrane organization, as well as antimicrobial defense. Finally, I briefly review therapeutic options that address this new pathogenic paradigm.

Lipid body-phagosome interaction in macrophages during infectious diseases: host defense or pathogen survival strategy?

Phagocytosis of invading microorganisms by specialized cells such as macrophages and neutrophils is a key component of the innate immune response. These cells capture and engulf pathogens and subsequently destroy them in intracellular vacuoles-the phagosomes. Pathogen phagocytosis and progression and maturation of pathogen-containing phagosomes, a crucial event to acquire microbicidal features, occurs in parallel with accentuated formation of lipid-rich organelles, termed lipid bodies (LBs), or lipid droplets. Experimental and clinical infections with different pathogens such as bacteria, parasites, and viruses induce LB accumulation in cells from the immune system. Within these cells, LBs synthesize and store inflammatory mediators and are considered structural markers of inflammation. In addition to LB accumulation, interaction of these organelles with pathogen-containing phagosomes has increasingly been recognized in response to infections and may have implications in the outcome or survival of the microorganism within host cells. In this review, we summarize our current knowledge on the LB-phagosome interaction within cells from the immune system, with emphasis on macrophages, and discuss the functional meaning of this event during infectious diseases.

Kawasaki disease: novel insights into etiology and genetic susceptibility.

Kawasaki disease (KD) is a vasculitis of young childhood that particularly affects the coronary arteries. Molecular analysis of the oligoclonal IgA response in acute KD led to production of synthetic KD antibodies. These antibodies identify intracytoplasmic inclusion bodies in acute KD tissues. Light and electron microscopic studies indicate that the inclusion bodies are consistent with aggregates of viral proteins and RNA. Advances in molecular genetic analysis and completion of the Human Genome Project have sparked a worldwide effort to identify genes associated with KD. A polymorphism of one such gene, ITPKC, a negative regulator of T cell activation, confers susceptibility to KD in Japanese populations and increases the risk of developing coronary artery abnormalities in both Japanese and U.S. children. Identification of the etiologic agent and of genes conferring KD susceptibility are the best means of improving diagnosis and therapy and enabling prevention of this important disorder of childhood.

Clinical associations and potential novel antigenic targets of autoantibodies directed against rods and rings in chronic hepatitis C infection.

BACKGROUND: Chronic hepatitis C virus (HCV) infection is frequently associated with extrahepatic autoimmune disorders while interferon (IFN) and ribavirin treatment may exacerbate these conditions. Autoantibodies from HCV patients identify a novel indirect immunofluorescence (IIF) pattern on HEp-2 cells characterized by cytoplasmic rods and rings (RR). Our objectives were to determine the prevalence and clinical associations of RR autoantibodies in HCV patients, and identify related novel autoantibody targets. METHODS: Sera from 315 patients with HCV (301 treatment naive, 14 treated with interferon and/or ribavirin) were analyzed for the presence of RR antibodies by IIF on commercially available HEp-2 cell substrates. Antibodies to inosine monophosphate dehydrogenase 2 (IMPDH2) and cytidine triphosphate synthase 1 (CTPS1) were detected by addressable laser bead assay and other potential targets were identified by immunoscreening a protein microarray. Clinical and demographic data including HCV genotype, mode of infection, prior antiviral therapy, and histological findings were compared between RR antibody positive (RR+) and negative (RR-) patients. RESULTS: The median age of the HCV cohort was 51 years, 61% were male, and 76% were infected with HCV genotype 1 (G1). Four percent (n=14) had been treated with IFN-based therapy (IFN monotherapy, n=3; IFN/ribavirin, n=11); all had a sustained virologic response. In total, 15 patients (5% of the cohort) were RR+. RR+ and RR- patients had similar demographic and clinical characteristics including age, sex, mode of HCV infection, prevalence of the G1 HCV genotype, and moderate to severe fibrosis. Nevertheless, RR+ patients were significantly more likely than RR- cases to have been treated with IFN-based therapy (33% vs. 3%; adjusted odds ratio 20.5 [95% confidence interval 5.1-83.2]; P<0.0005). Only 1/10 RR positive sera had detectable antibodies to IMPHD2 and none had antibodies to CTPS1. Potentially important autoantibody targets identified on protein arrays included Myc-associated zinc finger protein (MAZI) and ankyrin repeat motif. CONCLUSION: The majority of HCV patients with RR autoantibodies previously received IFN/ribavirin antiviral therapy. Further studies are necessary to determine the genesis of intracellular RR and elucidate the clinically relevant autoantigens as well as the clinical and prognostic significance of their cognate autoantibodies.

Immunization with live and dead Chlamydia muridarum induces different levels of protective immunity in a murine genital tract model: correlation with MHC class II peptide presentation and multifunctional Th1 cells.

Mice that were intranasally vaccinated with live or dead Chlamydia muridarum with or without CpG-containing oligodeoxynucleotide 1862 elicited widely disparate levels of protective immunity to genital tract challenge. We found that the frequency of multifunctional T cells coexpressing IFN-γ and TNF-α with or without IL-2 induced by live C. muridarum most accurately correlated with the pattern of protection against C. muridarum genital tract infection, suggesting that IFN-γ(+)-producing CD4(+) T cells that highly coexpress TNF-α may be the optimal effector cells for protective immunity. We also used an immunoproteomic approach to analyze MHC class II-bound peptides eluted from dendritic cells (DCs) that were pulsed with live or dead C. muridarum elementary bodies (EBs). We found that DCs pulsed with live EBs presented 45 MHC class II C. muridarum peptides mapping to 13 proteins. In contrast, DCs pulsed with dead EBs presented only six MHC class II C. muridarum peptides mapping to three proteins. Only two epitopes were shared in common between the live and dead EB-pulsed groups. This study provides insights into the role of Ag presentation and cytokine secretion patterns of CD4(+) T effector cells that correlate with protective immunity elicited by live and dead C. muridarum. These insights should prove useful for improving vaccine design for Chlamydia trachomatis.

TLR6-driven lipid droplets in Mycobacterium leprae-infected Schwann cells: immunoinflammatory platforms associated with bacterial persistence.

The mechanisms responsible for nerve injury in leprosy need further elucidation. We recently demonstrated that the foamy phenotype of Mycobacterium leprae-infected Schwann cells (SCs) observed in nerves of multibacillary patients results from the capacity of M. leprae to induce and recruit lipid droplets (LDs; also known as lipid bodies) to bacterial-containing phagosomes. In this study, we analyzed the parameters that govern LD biogenesis by M. leprae in SCs and how this contributes to the innate immune response elicited by M. leprae. Our observations indicated that LD formation requires the uptake of live bacteria and depends on host cell cytoskeleton rearrangement and vesicular trafficking. TLR6 deletion, but not TLR2, completely abolished the induction of LDs by M. leprae, as well as inhibited the bacterial uptake in SCs. M. leprae-induced LD biogenesis correlated with increased PGE(2) and IL-10 secretion, as well as reduced IL-12 and NO production in M. leprae-infected SCs. Analysis of nerves from lepromatous leprosy patients showed colocalization of M. leprae, LDs, and cyclooxygenase-2 in SCs, indicating that LDs are sites for PGE(2) synthesis in vivo. LD biogenesis Inhibition by the fatty acid synthase inhibitor C-75 abolished the effect of M. leprae on SC production of immunoinflammatory mediators and enhanced the mycobacterial-killing ability of SCs. Altogether, our data indicated a critical role for TLR6-dependent signaling in M. leprae-SC interactions, favoring phagocytosis and subsequent signaling for induction of LD biogenesis in infected cells. Moreover, our observations reinforced the role of LDs favoring mycobacterial survival and persistence in the nerve. These findings give further support to a critical role for LDs in M. leprae pathogenesis in the nerve.

The clinicopathologic significance of endothelial tubuloreticular inclusions in glomerular diseases.

BACKGROUND: The presence of tubuloreticular inclusions (TRIs) in endothelial cells (ECs) always evokes suspicion of an association with underlying viral infections or autoimmune diseases. However, other underlying diseases can be associated with TRI expression. Since identification of the underlying disease is of primary consideration for management of glomerulonephritis (GN), it is important to clarify the clinical significance of TRI expression. METHODS: The authors studied 104 renal biopsy cases having TRI. They investigated their clinicopathological profiles and focused on potential connections with underlying diseases. RESULTS: Among 104 renal biopsy cases, 62 cases (59.6%) were associated with lupus nephritis (LN) and 20 cases (19.2%) were associated with a viral infection (hepatitis B virus (13), hepatitis C virus (4), and human immunodeficiency virus (3)). Other underlying disease groups included membranous GN (MGN) (7), IgA nephropathy (7), Henoch-Schoenlein purpura (HSP) nephritis (2), and others (6). The incidence of TRIs in both LN and viral infections was significantly higher than for other diseases (p < 0.0001). Among 7 MGN cases, 2 cases were diabetes, 1 case was associated with lung cancer, another case with antineutrophilic cytoplasmic antibody (ANCA), and the others showed no evidence of systemic disease. On immunofluorescence (IF) study, 2 MGN cases, 2 IgA nephropathy cases, and 1 HSP nephritis case showed C1q deposition, with no evidence of SLE. CONCLUSIONS: TRIs were identified in MGN and other glomerular diseases, including IgA nephropathy and HSP nephritis. However, a diagnosis of LN should be considered because TRIs associated with a full-house IF pattern are usually found in LN.

Deciphering the contribution of lipid droplets in leprosy: multifunctional organelles with roles in Mycobacterium leprae pathogenesis.

Leprosy is an infectious disease caused by Mycobacterium leprae that affects the skin and nerves, presenting a singular clinical picture. Across the leprosy spectrum, lepromatous leprosy (LL) exhibits a classical hallmark: the presence of a collection of M. leprae-infected foamy macrophages/Schwann cells characterised by their high lipid content. The significance of this foamy aspect in mycobacterial infections has garnered renewed attention in leprosy due to the recent observation that the foamy aspect represents cells enriched in lipid droplets (LD) (also known as lipid bodies). Here, we discuss the contemporary view of LD as highly regulated organelles with key functions in M. leprae persistence in the LL end of the spectrum. The modern methods of studying this ancient disease have contributed to recent findings that describe M. leprae-triggered LD biogenesis and recruitment as effective mycobacterial intracellular strategies for acquiring lipids, sheltering and/or dampening the immune response and favouring bacterial survival, likely representing a fundamental aspect of M. leprae pathogenesis. The multifaceted functions attributed to the LD in leprosy may contribute to the development of new strategies for adjunctive anti-leprosy therapies.

HLA-B27 heavy chains distinguished by a micropolymorphism exhibit differential flexibility.

OBJECTIVE: Although the products of the HLA subtypes B*2705 and B*2709 differ only in residue 116 (Asp versus His) within their peptide-binding grooves, they are differentially associated with inflammatory rheumatic diseases such as ankylosing spondylitis (AS): B*2705 occurs in AS patients, whereas B*2709 is only rarely encountered. The reasons for this distinct association are still unclear but could include subtype-specific conformational and dynamic properties of these antigens. The present study was undertaken to investigate structural and dynamic differences between B*2705 and B*2709 and their possible relationship to subtype-specific disease association. METHODS: The membrane-distal segments of the B*2705 and B*2709 heavy chains were expressed in vitro and reconstituted together with beta(2)-microglobulin and a peptide. HLA-B27 complexes loaded with 2 self peptides (TIS [RRLPIFSRL] and pVIPR [RRKWRRWHL]) and a sequence-related viral peptide (pLMP2 [RRRWRRLTV]) were studied by isotope-edited infrared spectroscopy to detect differences in their structure and flexibility at physiologic temperature. RESULTS: Our analyses revealed the existence of subtype-specific conformational differences between the 2 HLA-B27 heavy chains at physiologic temperature, which are undetectable using x-ray crystallography. Irrespective of the bound peptide, the heavy chain of the B*2705 complex exhibited higher conformational flexibility than the B*2709 heavy chain. CONCLUSION: The present study demonstrates the existence of previously undetected systematic conformational and dynamic differences between the heavy chains of the 2 HLA-B27 subtypes. Since effector cell recognition of cells expressing HLA antigens is dependent on the dynamic properties of the interacting cell surface molecules, this HLA-B27 subtype-specific heavy chain flexibility could have a role in the distinct association of HLA-B27 subtypes with spondylarthritides.