Components Of Complement System Research Articles

Exposure to nanopollutants (nZnO) enhances the negative effects of hypoxia and delays recovery of the mussels’ immune system

Aquatic environments face escalating challenges from multiple stressors like hypoxia and nanoparticle exposure, with impact of these combined stressors on mussel immunity being poorly understood. We investigated the individual and combined effects of short-term and long-term hypoxia and exposure to zinc oxide nanoparticles (nZnO) on immune system of the mussels (Mytilus edulis). Hemocyte functional traits (mortality, adhesion capacity, phagocytosis, lysosomal abundance, and oxidative burst), and transcript levels of immune-related genes involved in pathogen recognition (the Toll-like receptors, the complement system components, and the adaptor proteins MyD88) were assessed. Short-term hypoxia minimally affected hemocyte parameters, while prolonged exposure led to immunosuppression, impacting hemocyte abundance, viability, phagocytosis, and defensin gene expression. Under normoxia, nZnO stimulated immune responses of mussel hemocytes. However, combined nZnO and hypoxia induced more pronounced and rapid immunosuppression than hypoxia alone, indicating a synergistic interaction. nZnO exposure hindered immune parameter recovery during post-hypoxic reoxygenation, suggesting persistent impact. Opposing trends were observed in pathogen-sensing and pathogen-elimination mechanisms, with a positive correlation between pathogen-recognition system activation and hemocyte mortality. These findings underscore a complex relationship and potential conflict between pathogen-recognition ability, immune function, and cell survival in mussel hemocytes under hypoxia and nanopollutant stress, and emphasize the importance of considering multiple stressors in assessing the vulnerability and adaptability of mussel immune system under complex environmental conditions of anthropogenically modified coastal ecosystems.

Discovery and Characterization of a New Class of C5aR1 Antagonists Showing In Vivo Activity.

C5a is an anaphylatoxin protein produced by the cleavage of the complement system's component C5 protein. It signals through the G-protein-coupled receptor C5a receptor 1 (C5aR1) to induce the chemotaxis of primarily neutrophils and monocytes and the release of inflammatory molecules. A large body of evidence linking C5aR1 signaling to acute and chronic inflammatory disorders has triggered interest in developing potent C5aR antagonists. Herein we report the discovery of new C5aR1 antagonistic chemical classes. Many representatives showed low nanomolar IC50 values in a C5aR1 β-arrestin-2 recruitment assay, inhibiting the migration of human neutrophils toward C5a and the internalization of the receptor in human whole blood. Two leading compounds were characterized further in vivo. Target engagement of the receptor by these two C5aR1 antagonists was demonstrated in vivo. In particular, the inhibition of migration in vitro with the two compounds further translated in a dose-dependent efficacy in a rat model of C5a-induced neutrophilia.

Safety Profile of Monoclonal Antibodies and Subsequent Drug Developments in the Treatment of Paroxysmal Nocturnal Hemoglobinuria.

Paroxysmal nocturnal hemoglobinuria (PNH) is a clonal stem cell disease characterized by intravascular hemolysis due to the targeting of affected red blood cells by the complement system. Eculizumab and ravulizumab are two monoclonal antibodies that inhibit the complement system's components and have been shown to significantly improve survival and quality of life. This review describes the role of these monoclonal antibodies in the treatment of PNH with an emphasis on their safety profile. The challenges in the use of these drugs and new drugs in various stages of drug development are also described, which may be helpful in addressing some of these challenges.

Sex- and species-associated differences in complement-mediated immunity in humans and rhesus macaques.

The complement system can be viewed as a "moderator" of innate immunity, "instructor" of humoral immunity, and "regulator" of adaptive immunity. While sex is known to affect humoral and cellular immune systems, its impact on complement in humans and rhesus macaques, a commonly used non-human primate model system, has not been well studied. To address this knowledge gap, we analyzed serum samples from 90 humans and 72 rhesus macaques for the abundance and activity of the complement system components. While sequences of cascade proteins were highly conserved, dramatically different levels were observed between species. Whereas the low levels detected in rhesus samples raised questions about the suitability of the test for use with macaque samples, differences in levels of complement proteins were observed in male and female humans. Levels of total and antibody-dependent deposition of C1q and C3b on a glycosylated antigen differed between humans and rhesus, suggesting differential recognition of glycans and balance between classical and alternative activation pathways. Functional differences in complement-mediated lysis of antibody-sensitized cells were observed in multiple assays and showed that human females frequently exhibited higher lytic activity than human males or rhesus macaques, which typically did not exhibit such sex-associated differences. Other differences between species and sexes were observed in more narrow contexts-for only certain antibodies, antigens, or assays. Collectively, these results expand knowledge of sex-associated differences in the complement system in humans, identifying differences absent from rhesus macaques.IMPORTANCEThe complement system is a critical part of host defense to many bacterial, fungal, and viral infections. In parallel, rich epidemiological, clinical, and biomedical research evidence demonstrates that sex is an important biological variable in immunity, and many sex-specific differences in immune system are intimately tied with disease outcomes. This study focuses on the intersection of these two factors to define the impact of sex on complement pathway components and activities. This work expands our knowledge of sex-associated differences in the complement system in humans and also identifies the differences that appear to be absent in rhesus macaques, a popular non-human primate model. Whereas differences between species suggest potential limitations in the ability of macaque model to recapitulate human biology, knowledge of sex-based differences in humans has the potential to inform clinical research and practice.

A Transcriptome Array-Based Approach to Link SGLT-2 and Intrarenal Complement C5 Synthesis in Diabetic Nephropathy.

Diabetic nephropathy is a common microvascular complication of diabetes mellitus. It is characterized by progressive chronic kidney disease (CKD) with decline of kidney function by hyperfiltration. On a mechanistic level, activation of the complement system has been implicated in the pathogenesis of diabetic nephropathy. Therefore, here we pursued a transcriptome array-based approach to link intrarenal SGLT-2 and the synthesis of distinct complement components in diabetic nephropathy. Publicly available datasets for SLC5A2 (encoding SGLT-2) and complement system components were extracted specifically from microdissected tubulointerstitial (healthy controls: n = 31, diabetic nephropathy: n = 17) and glomerular compartments (healthy controls: n = 21, diabetic nephropathy: n = 12). First, we compared tubulointerstitial and glomerular log2SLC5A2 mRNA expression levels and confirmed a predominant synthesis within the tubulointerstitial compartment. Among various complement components and receptors, the only significant finding was a positive association between SLC5A2 and the tubulointerstitial synthesis of the complement component C5 in diabetic nephropathy (p = 0.0109). Finally, intrarenal expression of SLC5A2 was associated predominantly with pathways involved in metabolic processes. Interestingly, intrarenal complement C5 synthesis was also associated with enrichment of metabolic signaling pathways, overlapping with SLC5A2 for "metabolism" and "biological oxidations". These observations could be of relevance in the pathogenesis of diabetic nephropathy and implicate a mechanistic link between SGLT-2 and intrarenal complement synthesis.

Cardiometabolic disease in Black African and Caribbean populations: an ethnic divergence in pathophysiology?

In the UK, populations of Black African and Caribbean (BAC) ethnicity suffer higher rates of cardiometabolic disease than White Europeans (WE). Obesity, leading to increased visceral adipose tissue (VAT) and intrahepatic lipid (IHL), has long been associated with cardiometabolic risk, driving insulin resistance and defective fatty acid/lipoprotein metabolism. These defects are compounded by a state of chronic low-grade inflammation, driven by dysfunctional adipose tissue. Emerging evidence has highlighted associations between central complement system components and adipose tissue, fatty acid metabolism and inflammation; it may therefore sit at the intersection of various cardiometabolic disease risk factors. However, increasing evidence suggests an ethnic divergence in pathophysiology, whereby current theories fail to explain the high rates of cardiometabolic disease in BAC populations. Lower fasting and postprandial TAG has been reported in BAC, alongside lower VAT and IHL deposition, which are paradoxical to the high rates of cardiometabolic disease exhibited by this ethnic group. Furthermore, BAC have been shown to exhibit a more anti-inflammatory profile, with lower TNF-α and greater IL-10. In contrast, recent evidence has revealed greater complement activation in BAC compared to WE, suggesting its dysregulation may play a greater role in the high rates of cardiometabolic disease experienced by this population. This review outlines the current theories of how obesity is proposed to drive cardiometabolic disease, before discussing evidence for ethnic differences in disease pathophysiology between BAC and WE populations.

A novel complement-fixing IgM antibody targeting GPC1 as a useful immunotherapeutic strategy for the treatment of pancreatic ductal adenocarcinoma

BackgroundPancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive cancers with a very low survival rate at 5 years. The use of chemotherapeutic agents results in only modest prolongation of survival and is generally associated with the occurrence of toxicity effects. Antibody-based immunotherapy has been proposed for the treatment of PDAC, but its efficacy has so far proved limited. The proteoglycan glypican-1 (GPC1) may be a useful immunotherapeutic target because it is highly expressed on the surface of PDAC cells, whereas it is not expressed or is expressed at very low levels in benign neoplastic lesions, chronic pancreatitis, and normal adult tissues. Here, we developed and characterized a specific mouse IgM antibody (AT101) targeting GPC1.MethodsWe developed a mouse monoclonal antibody of the IgM class directed against an epitope of GPC1 in close proximity to the cell membrane. For this purpose, a 46 amino acid long peptide of the C-terminal region was used to immunize mice by an in-vivo electroporation protocol followed by serum titer and hybridoma formation.ResultsThe ability of AT101 to bind the GPC1 protein was demonstrated by ELISA, and by flow cytometry and immunofluorescence analysis in the GPC1-expressing "PDAC-like" BXPC3 cell line. In-vivo experiments in the BXPC3 xenograft model showed that AT101 was able to bind GPC1 on the cell surface and accumulate in the BXPC3 tumor masses. Ex-vivo analyses of BXPC3 tumor masses showed that AT101 was able to recruit immunological effectors (complement system components, NK cells, macrophages) to the tumor site and damage PDAC tumor tissue. In-vivo treatment with AT101 reduced tumor growth and prolonged survival of mice with BXPC3 tumor (p < 0.0001).ConclusionsThese results indicate that AT101, an IgM specific for an epitope of GPC1 close to PDAC cell surface, is a promising immunotherapeutic agent for GPC1-expressing PDAC, being able to selectively activate the complement system and recruit effector cells in the tumor microenvironment, thus allowing to reduce tumor mass growth and improve survival in treated mice.

Systemic toxicity of snake venom metalloproteinases: Multi-omics analyses of kidney and blood plasma disturbances in a mouse model

Snakebite envenomation is classified as a Neglected Tropical Disease. Bothrops jararaca venom induces kidney injury and coagulopathy. HF3, a hemorrhagic metalloproteinase of B. jararaca venom, participates in the envenomation pathogenesis. We evaluated the effects of HF3 in mouse kidney and blood plasma after injection in the thigh muscle, mimicking a snakebite. Transcriptomic analysis showed differential expression of 31 and 137 genes related to kidney pathology after 2 h and 6 h, respectively. However, only subtle changes were observed in kidney proteome, with differential abundance of 15 proteins after 6 h, including kidney injury markers. N-terminomic analysis of kidney proteins showed 420 proteinase-generated peptides compatible with meprin specificity, indicating activation of host proteinases. Plasma analysis revealed differential abundance of 90 and 219 proteins, respectively, after 2 h and 6 h, including coagulation-cascade and complement-system components, and creatine-kinase, whereas a semi-specific search of N-terminal peptides indicated activation of endogenous proteinases. HF3 promoted host reactions, altering the gene expression and the proteolytic profile of kidney tissue, and inducing plasma proteome imbalance driven by changes in abundance and proteolysis. The overall response of the mouse underscores the systemic action of a hemorrhagic toxin that transcends local tissue damage and is related to known venom-induced systemic effects.

Comparative characteristics of the complement system in patients with C3-glomerulopathy and atypical hemolytic uremic syndrome of chronic course who suffered an acute episode of thrombotic microangiopathy

To compare changes in the complement system in C3-glomerulopathy (C3-GP) and atypical hemolytic uremic syndrome (aHUS) after the relief of an acute episode of thrombotic microangiopathy. The study included 8 patients diagnosed with C3-GP and 8 with aHUS in remission. The blood levels of the complement system components were determined: C3, C4, C3a, C5a, factor H (CFH), factor B (CFB), membrane-attacking complex (MAC), antibodies to C3b (anti-C3b-AT), the level of hemolytic activity (CH50), the content of factor D (CFD) in the urine. C3 and CH50 levels were within the reference range in both groups, however, in the C3-GP group they were at the lower limit, and C3 level was significantly lower than in the aHUS group: 0.56 [0.44; 0.96] vs 1.37 [1.16; 2.52] (p=0.003). CFB increased level was detected in both groups, but in the C3-GP group it was significantly lower than in the aHUS group - 275.1 [222.1; 356.6] vs 438.7 [323.3; 449.3] (p=0.010). C3a, C5a and MAC levels were increased in both groups, but the maximum was in the C3-GP group, and the MAC level in the C3-GP group was 2 times higher than that in aHUS, and these differences reached statistical significance - 123 555±6686 vs 5603±1294 (p=0.036). CFH and CFD levels was increased in both groups, but their highest values was in the aHUS group. Alternative complement pathway activation signs were present in both groups of patients with complement-mediated nephropathies, regardless the stage of the disease. In C3-GP, alternative complement pathway activation was more pronounced than in aHUS after the relief of an acute episode of thrombotic microangiopathy.

Diagnosis and treatment of glomerular diseases with a membranoproliferative glomerulonephritis (MPGN) pattern of injury

Membranoproliferative glomerulonephritis (MPGN) represents aheterogeneous group of diseases. The common feature of amembranoproliferative lesion pattern in the kidney biopsy can either be idiopathic/primary or-much more frequently-have asecondary cause. The historical classification into MPGN typesI toIII has largely been abandoned and replaced in recent years by apathogenesis-oriented classification. AMPGN with C1q, C3 and/or C4 deposits on light microscopy is referred to as immune complex GN (IC-GN), while aMPGN with dominant C3 deposits is referred to as C3 glomerulopathy (C3G). C3G is further divided into C3 glomerulonephritis (C3GN) and dense deposit disease (DDD). These diagnoses can only be made by akidney biopsy. Possible causes of MPGN are chronic infections (especially hepatitisB andC, bacterial infections, infections with protozoa), autoimmune diseases (especially lupus, rheumatoid arthritis) or malignancies (especially hematological malignancies). Particularly in the case of C3G acomprehensive analysis of the complement system components is strongly recommended. Due to the low incidence and the heterogeneous clinical appearance of MPGN therapeutic decisions must be made individually; an optimal general therapy is unknown, except that supportive treatment as with other glomerular diseases should be optimized. In the case of asecondary MPGN it is generally recommended to treat the potential cause of the MPGN. If significant proteinuria persists and eGFR remains > 30 ml/min/1.73 m2, treatment with systemic steroids and mycophenolate mofetil is recommended. Other treatment options on an individual level after evaluation and discussion of the risk-benefit ratio with the patient are rituximab and eculizumab. Rapidly progressive MPGN should be treated like ANCA-associated vasculitis. The recurrence rates after kidney transplantation are very high and treatment is challenging.

Biomarkers of the Complement System Activation (C3a, C5a, sC5b-9) in Serum of Patients before and after Liver Transplantation.

The liver has a huge impact on the functioning of our body and the preservation of homeostasis. It is exposed to many serious diseases, which may lead to the chronic failure of this organ, which is becoming a global health problem today. Currently, the final form of treatment in patients with end-stage (acute and chronic) organ failure is transplantation. The proper function of transplanted organs depends on many cellular processes and immune and individual factors. An enormous role in the process of acceptance or rejection of a transplanted organ is attributed to, among others, the activation of the complement system. The aim of this study was the evaluation of the concentration of selected biomarkers' complement system activation (C3a, C5a, and sC5b-9 (terminal complement complex)) in the serum of patients before and after liver transplantation (24 h, two weeks). The study was conducted on a group of 100 patients undergoing liver transplantation. There were no complications during surgery and no transplant rejection in any of the patients. All patients were discharged home 2-3 weeks after the surgery. The levels of all analyzed components of the complement system were measured using the ELISA method. Additionally, the correlations of the basic laboratory parameters-C-reactive protein (CRP), hemoglobin (Hb), total bilirubin, alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transpeptidase (GGTP), and albumin-with the parameters of the complement system (C3a, C5a, and sC5b-9) were determined. In our study, changes in the concentrations of all examined complement system components before and after liver transplantation were observed, with the lowest values before liver transplantation and the highest concentration two weeks after. The direct increase in components of the complement system (C3a, C5a, and sC5b-9) 24 h after transplantation likely affects liver damage after ischemia-reperfusion injury (IRI), while their increase two weeks after transplantation may contribute to transplant tolerance. Increasingly, attention is being paid to the role of C3a and CRP as biomarkers of damage and failure of various organs. From the point of view of liver transplantation, the most interesting correlation in our own research was found exactly between CRP and C3a, 24 h after the transplantation. This study shows that changes in complement activation biomarkers and the correlation with CRP in blood could be a prognostic signature of liver allograft survival or rejection.

Impact of Propeptide Cleavage on the Stability and Activity of a Streptococcal Immunomodulatory C5a Peptidase for Biopharmaceutical Development.

Posttranslational modifications of proteins can impact their therapeutic efficacy, stability, and potential for pharmaceutical development. The Group AStreptococcus pyogenesC5a peptidase (ScpA) is a multi-domain protein composed of an N-terminal signal peptide, a catalytic domain (including propeptide), three fibronectin domains, and cell membrane-associated domains. It is one of several proteins produced by Group AS. pyogenesknown to cleave components of the human complement system. After signal peptide removal, ScpA undergoes autoproteolysis and cleaves its propeptide for full maturation. The exact location and mechanism of the propeptide cleavage, and the impact of this cleavage on stability and activity, are not clearly understood, and the exact primary sequence of the final enzyme is not known. A form of ScpA with no autoproteolysis fragments of propeptide present may be more desirable for pharmaceutical development from a regulatory and a biocompatibility in the body perspective. The current study describes an in-depth structural and functional characterization of propeptide truncated variants of ScpA expressed inEscherichia colicells. All three purified ScpA variants, ScpA, 79ΔPro, and 92ΔPro, starting with N32, D79, and A92 positions, respectively, showed similar activity against C5a, which suggests a propeptide-independent activity profile of ScpA. CE-SDS and MALDI top-down sequencing analyses highlight a time-dependent propeptide autoproteolysis of ScpA at 37 °C with a distinct end point at A92 and/or D93. In comparison, all three variants of ScpA exhibit similar stability, melting temperatures, and secondary structure orientation. In summary, this work not only highlights propeptide localization but also provides a strategy to recombinantly produce a final mature and active form of ScpA without any propeptide-related fragments.

Conformational dynamics of complement protease C1r inhibitor proteins from Lyme disease– and relapsing fever–causing spirochetes

Borrelial pathogens are vector-borne etiological agents known to cause Lyme disease, relapsing fever, and Borrelia miyamotoi disease. These spirochetes each encode several surface-localized lipoproteins that bind components of the human complement system to evade host immunity. One borrelial lipoprotein, BBK32, protects the Lyme disease spirochete from complement-mediated attack via an alpha helical C-terminal domain that interacts directly with the initiating protease of the classical complement pathway, C1r. In addition, the Borrelia miyamotoi BBK32 orthologs FbpA and FbpB also inhibit C1r, albeit via distinct recognition mechanisms. The C1r-inhibitory activities of a third ortholog termed FbpC, which is found exclusively in relapsing fever-causing spirochetes, remains unknown. Here we report the crystal structure of the C-terminal domain of B. hermsii FbpC to a limiting resolution of 1.5 Å. We used surface plasmon resonance and assays of complement function to demonstrate that FbpC retains potent BBK32-like anti-complement activities. Based on the structure of FbpC, we hypothesized that conformational dynamics of the complement inhibitory domains of borrelial C1r inhibitors may differ. To test this, we utilized the crystal structures of the C-terminal domains of BBK32, FbpA, FbpB, and FbpC to carry out molecular dynamics simulations, which revealed borrelial C1r inhibitors adopt energetically favored open and closed states defined by two functionally critical regions. Taken together, these results advance our understanding of how protein dynamics contribute to the function of bacterial immune evasion proteins and reveals a surprising plasticity in the structures of borrelial C1r inhibitors.

Acquisition of Immune Privilege in GBM Tumors: Role of Prostaglandins and Bile Salts.

Based on the postulate that glioblastoma (GBM) tumors generate anti-inflammatory prostaglandins and bile salts to gain immune privilege, we analyzed 712 tumors in-silico from three GBM transcriptome databases for prostaglandin and bile synthesis/signaling enzyme-transcript markers. A pan-database correlation analysis was performed to identify cell-specific signal generation and downstream effects. The tumors were stratified by their ability to generate prostaglandins, their competency in bile salt synthesis, and the presence of bile acid receptors nuclear receptor subfamily 1, group H, member 4 (NR1H4) and G protein-coupled bile acid receptor 1 (GPBAR1). The survival analysis indicates that tumors capable of prostaglandin and/or bile salt synthesis are linked to poor outcomes. Tumor prostaglandin D2 and F2 syntheses are derived from infiltrating microglia, whereas prostaglandin E2 synthesis is derived from neutrophils. GBMs drive the microglial synthesis of PGD2/F2 by releasing/activating complement system component C3a. GBM expression of sperm-associated heat-shock proteins appears to stimulate neutrophilic PGE2 synthesis. The tumors that generate bile and express high levels of bile receptor NR1H4 have a fetal liver phenotype and a RORC-Treg infiltration signature. The bile-generating tumors that express high levels of GPBAR1 are infiltrated with immunosuppressive microglia/macrophage/myeloid-derived suppressor cells. These findings provide insight into how GBMs generate immune privilege and may explain the failure of checkpoint inhibitor therapy and provide novel targets for treatment.

Identification of autoimmune markers in pulmonary tuberculosis.

Pathogenesis of many autoimmune diseases is mainly promoted by poorly regulated and/or wrong targeted immune response to pathogens including M. tuberculosis. Autoimmunity is one of the processes with are characteristics of tuberculosis (Tbc). The aim was to determine the autoimmune clinical and immunological features in patients with pulmonary Tbc. A prospective comparative study was performed in 2017 - 2019 with the inclusion of 46 patients with Tbc. The trigger factors and clinical manifestations, autoantibodies, peripheral blood B cell subsets were stained with fluorochrome-conjugated monoclonal antibodies. 40 healthy volunteers in the control group, were matched for age with no chronic diseases, contacts with TB patients and changes in their laboratory parameters. A statistical analysis was done with GraphPad Prism 6, Statistica 10 (Statsoft) and MedCalc - version 18.2.1 values. There were no significant ASIA triggers in Tbc patients and control group. 21.1% of Tbc patients had a high level of a rheumatoid factor and in 47.4% complement system factor C3 was high; anti-MCV was detected in 60.7% of Tbc patients. Relative and absolute frequencies of "naïve" Bm1 cells and eBm5 were significantly decreased and activated pre-germinal-center Bm2' cells were significantly increased in Tbc patients. The CD24++CD38++ B cells were increased in Tbc vs control group (10.25% vs 5.42%), p < 0.001, and 19 cell/1μL (10; 290 vs 11 cell/1μL (6; 20), p = 0.029, respectively). The frequency of CXCR3+CCR4- Tfh1 cells was significantly lower in Tbc vs control one (26.52% vs. 31.00%, p = 0.004), while CXCR3-CCR4+ Tfh2 cells were increased in Tbc (20.31% vs. controls (16.56%, p = 0.030). The absolute numbers of Tfh1 cells were decreased in the Tbc vs. control (24 cell/1μL vs. 37 cell/1μL p = 0.005). The results of our study showed that the detection of a rheumatoid factor, the components of complement system and anti-MCV in complex with alterations in B cells and follicular Th cell subsets may indicate a presence of autoimmunity in the pathogenesis of tuberculosis, but they are not specific. The indicators of autoimmune-related provide new opportunities in the Tbc treatment.

The localization of Toll and Imd pathway and complement system components and their response to Vibrio infection in the nemertean Lineus ruber

BackgroundInnate immunity is the first line of defense against pathogens. In animals, the Toll pathway, the Imd pathway, the complement system, and lectins are well-known mechanisms involved in innate immunity. Although these pathways and systems are well understood in vertebrates and arthropods, they are understudied in other invertebrates.ResultsTo shed light on immunity in the nemertean Lineus ruber, we performed a transcriptomic survey and identified the main components of the Toll pathway (e.g., myD88, dorsal/dif/NFκB-p65), the Imd pathway (e.g., imd, relish/NFκB-p105/100), the complement system (e.g., C3, cfb), and some lectins (FreD-Cs and C-lectins). In situ hybridization showed that TLRβ1, TLRβ2, and imd are expressed in the nervous system; the complement gene C3-1 is expressed in the gut; and the lectins are expressed in the nervous system, the blood, and the gut. To reveal their potential role in defense mechanisms, we performed immune challenge experiments, in which Lineus ruber specimens were exposed to the gram-negative bacteria Vibrio diazotrophicus. Our results show the upregulation of specific components of the Toll pathway (TLRα3, TLRβ1, and TLRβ2), the complement system (C3-1), and lectins (c-lectin2 and fred-c5).ConclusionsTherefore, similarly to what occurs in other invertebrates, our study shows that components of the Toll pathway, the complement system, and lectins are involved in the immune response in the nemertean Lineus ruber. The presence of these pathways and systems in Lineus ruber, but also in other spiralians; in ecdysozoans; and in deuterostomes suggests that these pathways and systems were involved in the immune response in the stem species of Bilateria.

Association of Proliferative Diabetic Retinopathy in the Elderly with the Blood Complement System

A common complication of diabetes mellitus, mainly type 2, is diabetic retinopathy, among which the most unfavorable form for complete loss of vision is considered to be proliferative diabetic retinopathy. The participation of the complement system in the development of proliferative diabetic retinopathy is mainly devoted to experimental work on a limited number of blood complement components and without assessing their risk in the pathogenesis of the disease. The purpose of the study was to determine the association of components of the blood serum complement system with the development of proliferative diabetic retinopathy in the elderly. In clinical conditions, 115 patients 60–74 years old suffering from proliferative diabetic retinopathy and 48 patients of the same age with the absence of this ophthalmopathology were examined. The components of the blood complement system were studied by enzyme immunoassay and hemolytic method. The relative risk of the influence of the complement components was calculated according to the generally accepted method. There was a statistically significant increase in the blood serum of patients with proliferative diabetic retinopathy of most components of the complement system, with the exception of the C1 ing. and C5 components. The content of the C3a component increased especially to 127.6 ± 4.7 ng / ml versus 30.4 ± 3.5 ng/ml in the control, the C5a component to 5.6 ± 0.5 ng/ml versus 2.4 ± 0.3 ng/ml, and factor H to 228.7 ± 4.9 versus 106.3 ± 3.8 mng / ml, respectively. The highest value of the relative risk among the studied components is inherent in the C3a component of the blood complement with a reliable confidence interval of 4,451–5,103. The development of proliferative diabetic retinopathy in the elderly is associated with an increased content of C3a, C5a components and factor H in the blood serum, which can be used to develop targeted therapy for this disease.

Comparison of acute kidney injury following brain death between male and female rats

BackgroundClinical reports associate kidneys from female donors with worse prognostic in male recipients. Brain Death (BD) produces immunological and hemodynamic disorders that affect organ viability. Following BD, female rats are associated with increased renal inflammation interrelated with female sex hormone reduction. Here, the aim was to investigate the effects of sex on BD-induced Acute Kidney Injury (AKI) using an Isolated Perfused rat Kidney (IPK) model. MethodsWistar rats, females, and males (8 weeks old), were maintained for 4h after BD. A left nephrectomy was performed and the kidney was preserved in a cold saline solution (30 min). IPK was performed under normothermic temperature (37°C) for 90 min using WME as perfusion solution. AKI was assessed by morphological analyses, staining of complement system components and inflammatory cell markers, perfusion flow, and creatinine clearance. ResultsBD-male kidneys had decreased perfusion flow on IPK, a phenomenon that was not observed in the kidneys of BD-females (p < 0.0001). BD-male kidneys presented greater proximal (p = 0.0311) and distal tubule (p = 0.0029) necrosis. However, BD-female kidneys presented higher expression of eNOS (p = 0.0060) and greater upregulation of inflammatory mediators, iNOS (p = 0.0051), and Caspase-3 (p = 0.0099). In addition, both sexes had increased complement system formation (C5b-9) (p=0.0005), glomerular edema (p = 0.0003), and nNOS (p = 0.0051). ConclusionThe present data revealed an important sex difference in renal perfusion in the IPK model, evidenced by a pronounced reduction in perfusate flow and low eNOS expression in the BD-male group. Nonetheless, the upregulation of genes related to the proinflammatory cascade suggests a progressive inflammatory process in BD-female kidneys.

Peptide antitumor vaccines targeting HER2/neu

Antitumor vaccines are aimed at correcting cellular immunity by overcoming immunological tolerance with eluding surveillance due to the specific presentation of tumor-associated or tumor-specific antigens to immunocompetent cells.The purpose of this review was to study modern strategies for the development of antitumor vaccines containing epitopes of HER2/neu receptors acting as tumor-associated antigens. Approaches to the creation of such vaccines are classified by targeting the T-cell link or B-cells by the choice and length of the epitopes used or by the use of specific adjuvants.The review provides information on this topic, obtained from more than 50 publications of the last 20 years, found in the most significant sources of citation. The text is categorized for the convenience of perception by scientists of different specialties and is completed with a brief conclusion with an emphasis on development prospects. The results of clinical studies of vaccines with an analysis of the immunological features of the results of immunotherapy, mainly breast cancer with HER2/neu expression, are considered. Vaccines targeting different histocompatibility complexes are compared. The review traces the evolution of vaccine preparations from the simplest containing short peptide sequences to complex combined systems, including viral vectors. Attention is paid to various methodological approaches used in the development of such drugs: from computer design and phage display in experiments in vitro/in vivo. The emphasis is placed on the problem of a personalized approach to vaccination of an oncological patient associated with a mutation process occurring inside tumors and leading to the appearance of unique tumor-associated antigens. The participation of complement system components in antibody-mediated lysis of tumor cells induced by the presented vaccines is discussed.Thus, the review introduces readers to the existing directions of creating immune drugs designed to suppress the development of the tumor process by activating the body’s own immune forces and the prospect of their development.

Analysis of the relationship between human complement components C3 &amp; C4 deficiency and C– reactive protein levels as an indicator of the increase of microbial infections

The complement system is an important component of the immune system that consists of a group of plasma proteins produced by the liver and serving a defense function. As a result, the deficiency in any of the complement system components leads to the loss of the function of the deficient protein causing a specific clinical problem or disease. For that reason, this study was designed to investigate C3 and C4 deficiencies in young patients and to inspect the possibility of using C-Reactive Protein (CRP) test and the variation of C3 and C4 concentrations in children`s blood as an indicator of the onset of infection. This study was conducted in the children hospital in Benghazi city, Libya. The blood samples were collected from 446 children in all hospital units to examine the proportion of complement deficiency among those children and C3, C4 deficiency was set as an indicator of infection occurrence. The results of this study have shown a deficiency in complement proteins C3 and C4 were in 44 (10%) samples and 2 (0.4%) samples respectively, the female candidates had a higher rate of C3 and C4 deficiency than males. In addition, the CRP levels were elevated in 167 (55.9%) cases. Furthermore, the association between the increase of CRP levels and low levels of C3 and C4 was observed in 26 (8.7%) cases and 2 (0.6%) cases. These results suggest a strong association between complement proteins C3 and C4 deficiency and an elevation of CRP levels (P-Value=0.00), which supports the concept of using such association as an indicator of microbial infection