Involvement of Dectin-2 in the Innate Inflammatory Response Triggered by Influenza Virus Hemagglutinin

C-type lectin receptors (CLRs) are representative pattern recognition receptors that recognize microbial polysaccharides expressed on antigen-presenting cells. In the present study, we carried out further detailed analysis on the involvement of Dectin-2, a CLR that senses high mannose polysaccharide, in innate immune responses induced by influenza virus hemagglutinin (HA). Treatment of HA with periodate or PNGase F induced lower interleukin (IL)-12p40 secretion by conventional dendritic cells (DCs) compared with the untreated group. In contrast, treatment with O-glycosidase did not affect cytokine production. Green fluorescent protein expression in canonical Dectin-2-transducing cells was approximately 3% - 12% following HA stimulation, except with the A/H1N1pdm09 subtype HA. This expression was markedly reduced in cells possessing mutated amino acids in the carbohydrate recognition domain of Dectin-2, especially following stimulation with HA derived from the A/H3N2 subtype. Interferon (IFN)-α production from CD11c+Siglec-H+PDCA-1+ plasmacytoid DCs was significantly increased in Dectin-2 knockout mice compared with wild-type mice upon stimulation with HA except for the B/Yamagata lineage HA. These results suggested that Dectin-2 is involved in initiating inflammatory responses via mannose polysaccharide on HA. However, other mechanisms may function in the antiviral response, including the type I IFN axis.

Aflatoxin M1 Contamination of Milk and Its Products in Bomet County, Kenya

Aflatoxin M1 (AFM1) is a major carcinogenic compound that may be found in milk and dairy products resulting from ingestion of aflatoxin B1 by dairy animals. The study aimed at determining the level of aflatoxin M1 in milk and milk products from Bomet County. A total of 185 samples (150 raw milk and 35 processed milk and milk products) were randomly collected from milk collection sites and randomly selected milk kiosks respectively. The AFM1 was analyzed using a commercial ELISA kit (Ridascreen, aflatoxin M1 R-Biopharm, Product code, R5812, Darmstadt, Germany). Out of 185 samples investigated, 156 samples were positive for AFM1, an overall contamination rate of 84.32%. The samples with levels higher than the tolerance limit of 0.05 μg/l recommended by Food and Agriculture Organization (FAO) and World Health Organization (WHO) limits were 43.8% mainly contributed by the raw milk compared to processed milk (52.0% versus 8.6%). Processed milk had insignificant level of contamination with aflatoxin M1 (Median 0.00 (IQR: 0.00, 0.00 μg/l) with a minimum of 0.00 μg/l and a maximum of 0.69 μg/l. Raw milk showed significant contamination, median 0.09 (IQR: 0.00, 0.50) μg/l with a minimum of 0.00 μg/l and a maximum of 2.93 μg/l. Although there was no significant differences in AFM1 levels with study sites (P = 0.217);the median levels of aflatoxin M1 was high in sites 1, 3, and 7. The sites that had median aflatoxin M1 levels below the WHO/FAO acceptable limits of 0.05 μg/l were sites 2, 4 and 6. Due to high incidence of AFM1 contamination of milk and milk samples in Bomet County, there is need for regular monitoring and regulation of AFM1 contamination in milk and its products in the County.

Identification of Trichosporon spp. Strains by Sequencing D1/D2 Region and Sub-typing by Sequencing Ribosomal Intergenic Spacer Region of Ribosomal DNA

To re-identify and further group 25 isolates of Trichosporon spp. identified morphologically previously, sequences of D1/D2 region of large subunit （LSU） of ribosomal DNA （rDNA） of 25 tested strains for identification and those of ribosomal intergenic space 1 （IGS1） region of 11 strains for subgrouping were detected. The identifications of tested strains were changed except 6 strains. According to the alignment of the IGS1 region, 6 T. asahii isolates tested fell into 4 groups and 5 T. faecale isolates into 3 groups. Polymorphism of 2 T. japonicum isolates was found in 10 positions. With the alignments obtained in this research compared with the relative GenBank entries, it was found that T. asahii, T. faecale and T. japonicum species were divided into 7, 3 and 2 subtypes respectively. Morphological and biophysical methods are not sufficient for Trichosporon spp. identification. Sequencing becomes necessary for Trichosporon diagnosis. There is obvious diversity within a species.

Single-cell analysis for identification of T-cell clonotypes associated with IgG4 production of autoimmune pancreatitis

Introduction Autoimmune pancreatitis(AIP)is one of the recently established immunoglobulin G4-related diseases(IgG4-RD)[1].The detailed pathogenic mechanisms have been an intensive research area for prophylactic and therapeutic purposes because aberrant immune activation and tissue fibrosis in AIP are the major factors that worsen the disease outcomes in these patients.

Molecular mechanisms regulating NLRP3 inflammasome activation

Inflammasomes are multi-protein signaling complexes that trigger the activation of inflammatory caspases and the maturation of interleukin-1β. Among various inflammasome complexes, the NLRP3 inflammasome is best characterized and has been linked with various human autoinflammatory and autoimmune diseases. Thus, the NLRP3 inflammasome may be a promising target for anti-inflammatory therapies. In this review, we summarize the current understanding of the mechanisms by which the NLRP3 inflammasome is activated in the cytosol. We also describe the binding partners of NLRP3 inftammasome complexes activating or inhibiting the inflammasome assembly. Our knowledge of the mechanisms regulating NLRP3 inflammasome signaling and how these influence inflammatory responses offers further insight into potential therapeutic strategies to treat inflammatory diseases associated with dysregulation of the NLRP3 inflammasome,

Regulation of RIG-I-like receptor-mediated signaling:interaction between host and viral factors

Retinoic acid-inducible gene I(RIG-l)-like receptors(RLRs)are RNA sensor molecules that play essential roles in innate antiviral immunity.Among the three RLRs encoded by the human genome,RIG-1 and melanoma differentiation-associated gene 5,which contain N-terminal caspase recruitment domains,are activated upon the detection of viral RNAs in the cytoplasm of virus-infected cells.Activated RLRs induce downstream signaling via their interactions with mitochondrial antiviral signaling proteins and activate the production of type Ⅰ and Ⅲ interferons and inflammatory cytokines.Recent studies have shown that RLR-mediated signaling is regulated by interactions with endogenous RNAs and host proteins,such as those involved in stress responses and posttranslational modifications.Since RLR-mediated cytokine production is also involved in the regulation of acquired immunity,the deregulation of RLR-mediated signaling is associated with autoimmune and autoinflammatory disorders.Moreover,RLRmediated signaling might be involved in the aberrant cytokine production observed in coronavirus disease 2019.Since the discovery of RLRs in 2004,significant progress has been made in understanding the mechanisms underlying the activation and regulation of RLR-mediated signaling pathways.Here,we review the recent advances in the understanding of regulated RNA recognition and signal activation by RLRs,focusing on the interactions between various host and viral factors.

White-opaque Switching in Different Mating Type-like Locus Gene Types of Clinical Candida albicans Isolates

Background：Candida albicans （C.albicans） can become a pathogen causing superficial as well as life-threatening systemic infections,especially in immunocompromised patients.Many phenotypic attributes contribute to its capacity to colonize human organs.In our study,93 C.albicans isolates from patients of various candidiasis in a hospital of China were surveyed.We aimed to investigate the white-opaque （WO） switching competence,drug sensitivity,and virulence of mating type-like （MTL） a/α isolates.Methods：Internal transcribed spacer （ITS） gene and the MTL configuration were detected in all the isolates by reverse transcription-polymerase chain reaction.White/opaque phenotype and doubling time of cell growth were determined.The minimum inhibitory concentrations of antifungal agent were measured using broth microdilution method.Results：Sixty-four isolates （69.6%） were classified to serotype A,19 （20.6%） to serotype B,and 9 （9.8%） to serotype C.Moreover,phylogenetic analysis showed that these isolates were divided into four different subgroups of ITS genotypes.Most of our clinical isolates were MTLa/α type,while 6.8% remained MTLa or MTLα type.The frequency of opaque phenotype was 71.0% （66 isolates）.Following the guidelines of Clinical and Laboratory Standards Institute M27-A3,all isolates were susceptible to caspofungin and a few （0.6-3.2%） of them showed resistance against amphotericin B,flucytosine,fluconazole,itraconazole,and voriconazole.Conclusions：From these analyses,there were comparatively more C.albicans strains classified into serotype B,and the frequency of opaque phase strains was significant in the clinical isolates from China.Genetic,phenotypic,or drug susceptibility patterns were not significantly different from previous studies.MTLa/α isolates could also undergo WO switching which facilitates their survival.

New species in Aspergillus section Fumigati from reclamation sites in Wyoming (U.S.A.) and revision of A. viridinutans complex

The Aspergillus viridinutans complex includes morphologically similar,soil-inhabiting species.Although its species boundaries have not been fully defined,many isolates from the complex have been isolated as opportunistic human and animal pathogens.In the present study,these species were dominant in spoil sites subjected to various types of reclamation management after coal mining.These species were characterised using two different PCR-fingerprinting methods,sequence data from the β-tubulin(benA)and calmodulin(caM)genes,macro-and micromorphology(optical and scanning electron microscopy),maximum growth temperatures and mating experiments.In addition,RNA polymerase II gene(RPB2),actin(act1)and ITS sequences were deposited for the ex-type isolates of newly described species.The mating experiment results,phylogenetic analyses and ascospore morphology suggested the presence of five species in the A.viridinutans complex.Aspergillus aureolus(syn.Neosartorya aureola)was the only homothallic species.Three species,A.felis,A.udagawae(syn.N.udagawae)and A.wyomingensis sp.nov.,were heterothallic and their morphologically distinguishable teleomorph was induced by systematic mating experiments.Aspergillus viridinutans s.str.seems to be a very rare species and was represented only by the ex-type isolate in which the MAT1-1 locus was amplified.Aspegillus viridinutans and A.aureolus were typified in accordance with the rules of the new botanical code.Other species outside the A.viridinutans complex isolated from the reclamation sites were A.fumigatiaffinis and A.lentulus as well as two new sister species,A.brevistipitatus sp.nov.and A.conversis sp.nov.which were closely related each to other and to N.papuensis.Both new species are phylogenetically distant from all anamorphic species and resemble A.brevipes,A.duricaulis and A.unilateralis in micromorphology and are distinguishable from each other by the slower growth of A.conversis on all tested media.Interestingly,no isolate from the reclamation sites represented A.fumigatus s.str.which is usually reported as the dominant species from the section Fumigati in soil.