Immunogenetics最新文献

The X-linked hyper-IgM syndrome (X-HIGM1) is a rare primary immunodeficiency disorder (PID) caused by mutations in the gene encoding the CD154 protein, also known as CD40 ligand (CD40LG). X-HIGM1 is characterized by normal or elevated serum levels of IgM in association with decreased levels of IgG, IgA, and IgE. The CD40LG protein expressed on activated T cells interacts with its receptor protein, CD40, on B lymphocytes and dendritic cells. Mutations in the CD40LG gene lead to the production of an abnormal CD40L protein that fails to attach to its receptor, CD40 on B cells resulting in failure to produce IgG, IgA, and IgE antibodies. In the present study, we investigated the molecular defects underlying such a PID in a patient presenting with clinical history of pneumonia and acute respiratory distress syndrome (ARDS) at 7 months of age and diagnosed as transient hypogammaglobulinemia with decreased levels of IgG and increased levels of IgM. We have identified a novel and yet to be reported frame shift deletion of a single base pair (c.229delA) in exon 2 (p.Arg77AspfsTer6) of the CD40L gene ensuing the premature truncation of the protein by 6 amino acids by targeted gene sequencing. This frame shift mutation identified as a CD40L variant was found to be pathogenic which was also validated by Sanger sequencing. The in-silico analysis of c.229 del A mutation also predicted the change to be pathological affecting the structure and function of the CD40L (CD40L, CD154) protein and its protein-protein interaction properties.

MDA5, encoded by the IFIH1gene, is a cytoplasmic sensor of viral RNAs that triggers interferon (IFN) antiviral responses. Common and rare IFIH1 variants have been associated with the risk of type 1 diabetes and other immune-mediated disorders, and with the outcome of viral diseases. Variants associated with reduced IFN expression would increase the risk for severe viral disease. The MDA5/IFN pathway would play a critical role in the response to SARS-CoV-2 infection mediating the extent and severity of COVID-19. Here, we genotyped a cohort of 477 patients with critical ICU COVID-19 (109 death) for three IFIH1 functional variants: rs1990760 (p.Ala946Thr), rs35337543 (splicing variant, intron 8 + 1G > C), and rs35744605 (p.Glu627Stop). The main finding of our study was a significant increased frequency of rs1990760 C-carriers in early-onset patients (< 65 years) (p = 0.01; OR = 1.64, 95%CI = 1.18-2.43). This variant was also increased in critical vs. no-ICU patients and in critical vs. asymptomatic controls. The rs35744605 C variant was associated with increased blood IL6 levels at ICU admission. The rare rs35337543 splicing variant showed a trend toward protection from early-onset critical COVID-19. In conclusion, IFIH1 variants associated with reduced gene expression and lower IFN response might contribute to develop critical COVID-19 with an age-dependent effect.

Immunotherapy plus tyrosine kinase inhibitor (IO-TKI) has become the standard first-line therapy for advanced renal cell carcinoma (RCC). However, the modest response rate of IO-TKI therapy and the absence of biomarkers limited the selection of treatment strategies for RCC patients. There were three cohorts enrolled: two from our facility (ZS-MRCC and ZS-HRRCC) and one from a clinical study (JAVELIN-101). By RNA sequencing, the expression of ADAM9 in each sample was measured. By flow cytometry and immunohistochemistry, immune infiltration and T cell function were examined. Primary outcomes were established as treatment response and progression-free survival (PFS). Patients with low-ADAM9 expression had a higher objective response rate (56.5% vs 13.6%, P = 0.01) and longer PFS in both cohorts. In the ZS-HRRCC cohort, the expression of ADAM9 was associated with increased tumor-infiltrating T cells, which was proved by immunohistochemistry (P < 0.05) and flow cytometry (Spearman's ρ = 0.42, P < 0.001). In the high-ADAM9 group, CD8⁺ and CD4⁺ T cells revealed an exhausted phenotype with decreased GZMB (Spearman's ρ =  - 0.31, P = 0.05, and Spearman's ρ =  - 0.49, P < 0.001, respectively), and fewer Macrophages were identified. A predictive RFscore was further constructed by random forest approach, involving ADAM9 and immunologic genes. Only in the subgroup with the lower RFscore did IO-TKI outperform TKI monotherapy. High-ADAM9 expression was associated with immunosuppression and IO-TKI resistance. Expression of ADAM9 was also associated with the exhaustion and dysfunction of T cells. ADAM9-based RFscore has the potential to be used as a biomarker to distinguish the optimal patient treatment methods between IO-TKI and TKI monotherapy.

Lung adenocarcinoma (LUAD) is the major type of lung cancer and is one of the deadliest cancers worldwide. IL4I1, as a gene associated with unsatisfactory prognosis, is involved in tumor immune escape, but its immune regulatory mechanism in LUAD is limited. Bioinformatics analysis was applied to analyze the differentially expressed mRNAs and enriched signaling pathways in LUAD tissue. Quantitative real-time polymerase chain reaction (qRT-PCR) was manipulated to test IL4I1 expression. We carried out several methods to examine cell functions: CCK-8 to measure LUAD cell proliferation; flow cytometry to determine cell apoptosis; Western blot to assess the expression of JAK/STAT pathway-related proteins and PD-L1; T cell cytotoxicity assay to evaluate the effect of IL4I1 on the immune escape of LUAD cells. Through bioinformatics analysis, IL4I1 was verified to be highly expressed in LUAD tissue, participate in the modulation of JAK/STAT signaling pathway, and be positively associated with CD274 (PD-L1) expression. Cell function experiments indicated that silencing IL4I1 notably repressed LUAD cell proliferation and induced apoptosis. IL4I1 silence would block JAK/STAT signaling pathway, but this effect could be reversed by RO8191 activator treatment. Moreover, IL4I1 silence suppressed PD-L1 expression and facilitated T cell cytotoxicity, while its inhibitory impact on PD-L1 expression and immune escape of LUAD cells could be reversed by atezolizumab treatment. Overall, we confirmed that IL4I1 promoted the malignant cell behaviors and immune escape of LUAD through JAK/STAT signaling pathway. IL4I1 has the potential to be a diagnostic biomarker for LUAD.

Heritable polymorphisms within the human IgG locus, collectively termed allotypes, have often been linked by statistical associations, but rarely mechanistically, to a wide range of disease states. One potential explanation for these associations is that IgG allotype alters host cell receptors' affinity for IgG, dampening or enhancing an immune response depending on the nature of the change and the receptors. In this work, a panel of allotypic antibody variants were evaluated using multiplexed, label-free biophysical methods and cell-based functional assays to determine what effect, if any, human IgG polymorphisms have on antibody function. While we observed several differences in FcγR affinity among allotypes, there was little evidence of dramatically altered FcγR-based effector function or antigen recognition activity associated with this aspect of genetic variability.

We previously reported that nonobese diabetic (NOD) congenic mice (NOD.c3c4 mice) developed an autoimmune biliary disease (ABD) with similarities to human primary biliary cholangitis (PBC), including anti-mitochondrial antibodies and organ-specific biliary lymphocytic infiltrates. We narrowed the possible contributory regions in a novel NOD.Abd3 congenic mouse to a B10 congenic region on chromosome 1 ("Abd3") and a mutated Pkhd1 gene (Pkhd1^del36-67) upstream from Abd3, and we showed via backcrossing studies that the NOD genetic background was necessary for disease. Here, we show that NOD.Abd3 mice develop anti-PDC-E2 autoantibodies at high levels, and that placing the chromosome 1 interval onto a scid background eliminates disease, demonstrating the critical role of the adaptive immune system in pathogenesis. While the NOD genetic background is essential for disease, it was still unclear which of the two regions in the Abd3 locus were necessary and sufficient for disease. Here, using a classic recombinant breeding approach, we prove that the mutated Pkhd1^del36-67 alone, on the NOD background, causes ABD. Further characterization of the mutant sequence demonstrated that the Pkhd1 gene is disrupted by an ETnII-beta retrotransposon inserted in intron 35 in an anti-sense orientation. Homozygous Pkhd1 mutations significantly affect viability, with the offspring skewed away from a Mendelian distribution towards NOD Pkhd1 homozygous or heterozygous genotypes. Cell-specific abnormalities, on a susceptible genetic background, can therefore induce an organ-specific autoimmunity directed to the affected cells. Future work will aim to characterize how mutant Pkhd1 can cause such an autoimmune response.

The involvement of small nucleolar RNA host gene 3 (SNHG3) in cancer regulation has been reported. This study attempted to deeply investigate the molecular regulatory mechanism of SNHG3 on malignant progression of hepatocellular carcinoma (HCC). According to TCGA analysis, high SNHG3 expression was a risk factor for poor prognosis of HCC patients. Therefore, we further detected the mRNA level of SNHG3 in HCC tissue and cells. It was found that SNHG3 was upregulated in HCC tissue and cells. Afterwards, CCK-8 and flow cytometry assays further proved that silencing SNHG3 inhibited HCC cell proliferation while inducing cell apoptosis and G0/G1 phase arrest. It was also attested in vivo experiments that silencing SNHG3 could reduce the volume and weight of tumors and downregulate the Ki-67 expression to suppress HCC tumor growth. Next, it was discovered that SNHG3 increased the binding of E2F1 and NEIL3 promoter region, thereby activating the transcription feature of NEIL3. Lastly, rescue assays indicated that NEIL3 participated in SNHG3-mediated HCC cell cycle, apoptosis and proliferation. All in all, this study revealed the specific regulatory mechanism of SNHG3 in HCC to enable SNHG3 a hopeful marker for HCC diagnosis and treatment.

Multiple novel immunoglobulin-like transcripts (NILTs) have been identified from salmon, trout, and carp. NILTs typically encode activating or inhibitory transmembrane receptors with extracellular immunoglobulin (Ig) domains. Although predicted to provide immune recognition in ray-finned fish, we currently lack a definitive framework of NILT diversity, thereby limiting our predictions for their evolutionary origin and function. In order to better understand the diversity of NILTs and their possible roles in immune function, we identified five NILT loci in the Atlantic salmon (Salmo salar) genome, defined 86 NILT Ig domains within a 3-Mbp region of zebrafish (Danio rerio) chromosome 1, and described 41 NILT Ig domains as part of an alternative haplotype for this same genomic region. We then identified transcripts encoded by 43 different NILT genes which reflect an unprecedented diversity of Ig domain sequences and combinations for a family of non-recombining receptors within a single species. Zebrafish NILTs include a sole putative activating receptor but extensive inhibitory and secreted forms as well as membrane-bound forms with no known signaling motifs. These results reveal a higher level of genetic complexity, interindividual variation, and sequence diversity for NILTs than previously described, suggesting that this gene family likely plays multiple roles in host immunity.

Polymorphism of the major histocompatibility complex (MHC), DAB1 gene was characterized for the first time in the European bitterling (Rhodeus amarus), a freshwater fish employed in studies of host-parasite coevolution and mate choice, taking advantage of newly designed primers coupled with high-throughput amplicon sequencing. Across 221 genotyped individuals, we detected 1-4 variants per fish, with 28% individuals possessing 3-4 variants. We identified 36 DAB1 variants, and they showed high sequence diversity mostly located within predicted antigen-binding sites, and both global and codon-specific excess of non-synonymous mutations. Despite deep divergence between two major allelic lineages, functional diversity was surprisingly low (3 supertypes). Overall, these findings suggest the role of positive and balancing selection in promotion and long-time maintenance of DAB1 polymorphism. Further investigations will clarify the role of pathogen-mediated selection to drive the evolution of DAB1 variation.