Human Innate Immunity Research Articles

Host defense against the infection of Klebsiella pneumoniae: New strategy to kill the bacterium in the era of antibiotics?

Klebsiella pneumoniae (K. pneumoniae) is a typical gram-negative iatrogenic bacterium that often causes bacteremia, pneumonia and urinary tract infection particularly among those with low immunity. Although antibiotics is the cornerstone of anti-infections, the clinical efficacy of β-lactamase and carbapenems drugs has been weakened due to the emergence of drug-resistant K. pneumoniae. Recent studies have demonstrated that host defense plays a critical role in killing K. pneumoniae. Here, we summarize our current understanding of host immunity mechanisms against K. pneumoniae, including mechanical barrier, innate immune cells, cellular immunity and humoral immunity, providing a theoretical basis and the new strategy for the clinical treatment of K. pneumoniae through improving host immunity.

Complement-regulatory biomaterial coatings: Activity and selectivity profile of the factor H-binding peptide 5C6

The use of biomaterials in modern medicine has enabled advanced drug delivery strategies and led to reduced morbidity and mortality in a variety of interventions such as transplantation or hemodialysis. However, immune-mediated reactions still present a serious complication of these applications. One of the drivers of such reactions is the complement system, a central part of humoral innate immunity that acts as a first-in-line defense system in its own right but also coordinates other host defense responses. A major regulator of the complement system is the abundant plasma protein factor H (FH), which impairs the amplification of complement responses. Previously, we could show that it is possible to recruit FH to biomedical surfaces using the phage display-derived cyclic peptide 5C6 and, consequently, reduce deposition of C3b, an activation product of the complement system. However, the optimal orientation of 5C6 on surfaces, structural determinants within the peptide for the binding, and the exact binding region on FH remained unknown. Here, we show that the cyclic core and C-terminal region of 5C6 are essential for its interaction with FH and that coating through its N-terminus strongly increases FH recruitment and reduces C3-mediated opsonization in a microparticle-based assay. Furthermore, we could demonstrate that 5C6 selectively binds to FH but not to related proteins. The observation that 5C6 also binds murine FH raises the potential for translational evaluation in animal models. This work provides important insight for the future development of 5C6 as a probe or therapeutic entity to reduce complement activation on biomaterials. Statement of significanceBiomaterials have evolved into core technologies critical to biomedical and drug delivery applications alike, yet their safe and efficient use may be adversely impacted by immune responses to the foreign materials. Taking inspiration from microbial immune evasion strategies, our group developed a peptide-based surface coating that recruits factor H (FH), a host regulator of the complement system, from plasma to the material surface and prevents unwanted activation of this innate immunity pathway. In this study, we identified the molecular determinants that define the interaction between FH and the coated peptide, developed tethering strategies with largely enhanced binding capacity and provided important insight into the target selectivity and species specificity of the FH-binding peptide, thereby paving the way for preclinical development steps.

Polymorphisms of leukocyte genes human and congenital antigen immunity associated with different the severity of the course of the new coronavirus infections

The most significant single nucleotide human leukocyte antigen genes polymorphisms and innate immunity genes associated with varying degrees of acute respiratory infection severity are consideredCOVID-19 caused by the SARS-CoV-2 coronavirus. As data accumulated, it became clear that the SARS-CoV-2 virus exhibits significant regional, ethnic, and individual specificity. This is due to the population groups genetic characteristics. This is necessary to reliably know the human genotype relationship with the COVID-19 course severity (asymptomatic, mild, moderate, severe, and extremely severe up to fatal outcomes) for more successful therapy and vaccination. At the same time, it was also known that the innate immunity system is on the first line of defense against the pathogenic penetration into the body, and the human leukocyte antigen system encodes molecules of the same name on the surface of cells that present various antigens, including viral infection pathogens, and determine the severity of the course of many diseases; therefore, these systems genes. This approach makes it possible to assess the likelihood of a severe and extremely severe disease course in healthy and infected people, which in turn contributes to the correct therapy strategy, pharmacotherapy, and vaccination, as well as to create new antiviral therapeutic and preventive medicines. The genetically determined immune response heterogeneity to SARS-CoV-2 infection requires further study, since there is no unambiguous opinion about the leading mechanism that determines disease severity.

Changes of blood serum cytokine profile in the patients with papillomavirus infection before and after therapeutic pregravid preparation

Human papillomavirus is one of the most common sexually transmitted viruses. The state of the immune system is fundamental to the outcome of infectious processes of viral and bacterial genesis, thus determining the quality of pre-gravidar preparation. The purpose of present study was to perform a comprehensive analysis of pro- and anti-inflammatory cytokines in papillomavirus infection and to provide immunological assessment of therapeutic efficiency in women. Materials and methods: 137 patients with papillomavirus infection were observed, at the average age of 312.5 years old. The study consisted of 2 stages: stage 1 included analysis of humoral innate immunity in women of the main group, distributed according to etiological factor, i.e., G-I was with papillomavirus infection (PVI); G-II presented with papillomavirus and herpetic infection (PVI + HVI 1/2 type); G-III included the patients with papillomavirus and Chlamydia infection (PVI + Trash.). At Stage 2, we performed immunological analysis of the therapeutic efficiency for PVI: in G-IA group with papillomavirus infection (PVI) we used Inosine pranobex (n = 11); in the IB group, Solanum tuberosum was applied (n = 10); in G-II A group with papillomavirus and herpes infection (PVI+HVI 1/2 type), we used Valacyclovir + Inosine pranobex (n = 24); in G-IIB patients Valacyclovir + Solanum tuberosum were administered (n = 23); for G-IIIA group with papillomavirus and chlamydia infection (PVI + Trash.) Doxycycline + Inosine pranobex were used (n = 20); the patients from IIIB group were treated with Doxycycline + Solanum tuberosum (n = 19). Determination of levels of IL-17A, IL-12 p70, IL-12 p40, IL- 13 in blood serum was carried out using specific reagents from RD Diagnostics Inc. (USA). Results: Before therapy, an increase in IL-17 and IL-13 (p 0.05), and a pronounced deficiency of IL-12 p40 and IL-12 p70 (p 0.001) were observed in blood serum of the patients. After the course of therapy, a decrease in IL-13 and an increase in IL-12 p40 and IL-12 p 70 were found. The IL-17 level remained without dynamic changes. The applied therapeutic approaches had a positive effect in all studied groups of patients, regardless of the drug administered.

Roles of Vitamins in Immunity and COVID-19: A Literature Review

SARS-CoV-2 is a severe acute respiratory virus that causes Coronavirus Disease-19 (COVID-19). Even before the COVID-19 pandemic, diet was undeniably important in immunity. In order to be more resilient during and after the pandemic, understanding the role of vitamins is crucial. This review aims to explore the role of vitamins in supporting the immune system and its correlation to COVID-19. The article search was done using five electronic databases (i.e., Google Scholar, Semantic Scholar, ScienceDirect, PubMed, and PMC). Some of the keywords utilized in the literature search were “vitamin A and immunity” OR “vitamin B and immunity” OR “vitamin C and immunity” OR “vitamin D and immunity” OR “vitamin E and immunity”. A total of 51 articles was assessed in this literature review. Research finds vitamin A plays a role in both innate immune system cell function and humoral immunity by regulating, differentiating, and maturing immune system cells. Vitamin B complex primarily reduces inflammation by lowering serum C-reactive protein levels (CRP), while vitamin C strengthens epithelial barriers, phagocytes, T and B lymphocytes, and inflammatory mediators, to improve the immune system. Vitamin D acts as a mediator in the vitamin D receptor (VDR), an inner immune system component that regulates the humoral and adaptive immune systems through unique genetic transcriptions. Finally, vitamin E acts as an antioxidant, lowering the production of reactive oxygen and nitrogen species (ROS and RNS). In conclusion, all vitamins are essential in improving individual’s immune system that prevent from infectious diseases including COVID-19.

Spatiotemporal regulation of human IFN-ε and innate immunity in the female reproductive tract.

Although published studies have demonstrated that IFN-ε has a crucial role in regulating protective immunity in the mouse female reproductive tract, expression and regulation of IFN-ε in the human female reproductive tract (hFRT) have not been characterized to our knowledge. We obtained hFRT samples from a well-characterized cohort of women to enable us to comprehensively assess ex vivo IFN-ε expression in the hFRT at various stages of the menstrual cycle. We found that among the various types of IFNs, IFN-ε was uniquely, selectively, and constitutively expressed in the hFRT epithelium. It had distinct expression patterns in the surface and glandular epithelia of the upper hFRT compared with basal layers of the stratified squamous epithelia of the lower hFRT. There was cyclical variation of IFN-ε expression in the endometrial epithelium of the upper hFRT and not in the distal FRT, consistent with selective endometrial expression of the progesterone receptor and regulation of the IFNE promoter by progesterone. Because we showed IFN-ε stimulated important protective IFN-regulated genes in FRT epithelium, this characterization is a key element in understanding the mechanisms of hormonal control of mucosal immunity.

Динаміка показників імунологічного статусу та ліпідного обміну у хворих на хронічну ішемічну хворобу серця в зіставленні з розвитком серцево-судинних подій протягом тривалого спостереження

Мета роботи – оцінити зв’язок динаміки імунологічних показників і даних обміну ліпідів та ліпопротеїнів крові у хворих на хронічну ішемічну хворобу серця (ІХС) з розвитком серцево-судинних подій порівняно з пацієнтами з ІХС без таких подій протягом 6,5 року спостереження.Матеріали і методи. Хворі на ІХС зі стабільною стенокардією були розподілені на дві групи: до першої групи (n=46) увійшли пацієнти з хронічною ІХС без перенесених серцево-судинних подій за час спостереження, до другої групи (n=36) – пацієнти з хронічною ІХС з виникненням таких подій за 6,5 року спостереження. Матеріалом імунологічного дослідження була периферична венозна кров. Для визначення показників клітинного і гуморального вродженого та адаптивного імунітету в сироватці крові й супернатантах мононуклеарних клітин використовували імуноферментний аналіз. Результати та обговорення. Зіставлення динаміки показників Т-клітинного імунітету: в другій та першій групах динаміка медіан рівня Т-супресорів (CD8) – з 22 до 33 % (р=0,018) проти з 27 до 33 % (р=0,10), кількості лімфоцитів зі схильністю до апоптозу в другій та першій групах – з 18 до 27 % (р=0,11) проти з 12 до 29 % (р=0,002). Між пацієнтами з хронічною ІХС з розвитком серцево-судинних подій упродовж 6,5 року порівняно з пацієнтами без подій динаміка медіан рівня С-реактивного білка відповідно була такою – з 6,7 до 7,8 мг/л (р=0,043) проти з 3,2 до 3,8 мг/л (р=0,024), вмісту інтерлейкіну-6 (ІЛ-6) у мононуклеарних клітинах – з 2239 до 5788 пг/мл (р=0,47) проти з 2127 до 5544 пг/мл (р=0,005), ІЛ-8 у мононуклеарних клітинах – з 2305 до 3536 пг/мл (р=0,028) проти з 1980 до 3820 пг/мл (р=0,0004), протизапального ІЛ-10 у мононуклеарних клітинах – з 95 до 44 пг/мл (р=0,69) проти з 220 до 68 пг/мл (р=0,97). У пацієнтів другої групи порівняно з першою динаміка медіан рівнів загального холестерину становила відповідно з 6,9 до 6,0 ммоль/л (р=0,07) проти з 5,9 до 6,5 ммоль/л (р=0,15), тригліцеридів – з 2,2 до 1,1 ммоль/л (р=0,08) проти з 1,9 до 1,5 ммоль/л (р=0,030), холестерину ліпопротеїнів високої щільності – з 1,15 до 1,28 ммоль/л (р=0,89) проти з 1,10 до 1,40 ммоль/л (р=0,0005), динаміка медіан ступеня перекисної модифікації ліпопротеїнів: з 7,1 до 2,6 ум. од. (р=0,14) проти з 5,4 до 3,1 ум. од. (р=0,0008), вільнорадикального окиснення білків – з 3,3 до 5,0 (р=0,028) проти з 4,6 до 5,1 ум. од. (р=0,54).Висновки. У хворих на хронічну ІХС упродовж 6,5 року статистично значуще зростає активність імунного запалення. Розвиток серцево-судинних подій за цей період не супроводжується особливостями збільшення показників імунного запалення, особливостями змін досліджуваних показників гуморальної ланки набутого імунітету та показників системи фагоцитів порівняно з пацієнтами без таких подій. Виникнення серцево-судинних подій супроводжується більшою активацією Т-лімфоцитів та меншим зростанням кількості лімфоцитів зі схильністю до апоптозу, статистично значущим зростанням за цей період активності вільнорадикального окиснення білків порівняно з пацієнтами без таких ускладнень. Відсутність серцево-судинних подій поєднується зі статистично значущим зростанням рівня холестерину ліпопротеїнів високої щільності на тлі терапії статинами.

Genetic targeting or pharmacological inhibition of galectin-3 dampens microglia reactivity and delays retinal degeneration

BackgroundDysfunctional humoral and cellular innate immunity are key components in the development and progression of age-related macular degeneration (AMD). Specifically, chronically activated microglia and their disturbed regulatory system contribute to retinal degeneration. Galectin-3, a β-galactose binding protein, is a potent driver of macrophage and microglia activation and has been implicated in neuroinflammation, including neurodegenerative diseases of the brain. Here, we hypothesized that genetic deficiency of galectin-3 or its modulation via TD139 dampens mononuclear phagocyte reactivity and delays retinal degeneration.MethodsGalectin-3 expression in AMD patients was analyzed by immunohistochemical stainings. Galectin-3 knockout and BALB/cJ mice were exposed to white bright light with an intensity of 15,000 lux for 1 h and Cx3cr1GFP/+ mice to focal blue light of 50,000 lux for 10 min. BALB/cJ and Cx3cr1GFP/+ mice received intraperitoneal injections of 15 mg/kg TD139 or vehicle for five consecutive days, starting one day prior to light exposure. The effects of galectin-3 deficiency or inhibition on microglia were analyzed by immunohistochemical stainings and in situ hybridization of retinal sections and flat mounts. Pro-inflammatory cytokine levels in the retina and retinal pigment epithelium (RPE) were quantified by qRT-PCR and transcriptomic changes were analyzed by RNA-sequencing. Retinal thickness and structure were evaluated by optical coherence tomography.ResultsWe found that galectin-3 expression was strongly upregulated in reactive retinal mononuclear phagocytes of AMD patients and in the two related mouse models of light-induced retinal degeneration. The experimental in vivo data further showed that specific targeting of galectin-3 by genetic knockout or administration of the small-molecule inhibitor TD139 reduced microglia reactivity and delayed retinal damage in both light damage conditions.ConclusionThis study defines galectin-3 as a potent driver of retinal degeneration and highlights the protein as a drug target for ocular immunomodulatory therapies.

Stealthy microbes: How Neisseria gonorrhoeae hijacks bulwarked iron during infection.

Transition metals are essential for metalloprotein function among all domains of life. Humans utilize nutritional immunity to limit bacterial infections, employing metalloproteins such as hemoglobin, transferrin, and lactoferrin across a variety of physiological niches to sequester iron from invading bacteria. Consequently, some bacteria have evolved mechanisms to pirate the sequestered metals and thrive in these metal-restricted environments. Neisseria gonorrhoeae, the causative agent of the sexually transmitted infection gonorrhea, causes devastating disease worldwide and is an example of a bacterium capable of circumventing human nutritional immunity. Via production of specific outer-membrane metallotransporters, N. gonorrhoeae is capable of extracting iron directly from human innate immunity metalloproteins. This review focuses on the function and expression of each metalloprotein at gonococcal infection sites, as well as what is known about how the gonococcus accesses bound iron.

Enhanced development of functional human NK cells in NOD-scid-IL2rgnull mice expressing human IL15.

Human innate immunity plays a critical role in tumor surveillance and in immunoregulation within the tumor microenvironment. Natural killer (NK) cells are innate lymphoid cells that have opposing roles in the tumor microenvironment, including NK cell subsets that mediate tumor cell cytotoxicity and subsets with regulatory function that contribute to the tumor immune suppressive environment. The balance between effector and regulatory NK cell subsets has been studied extensively in murine models of cancer, but there is a paucity of models to study human NK cell function in tumorigenesis. Humanized mice are a powerful alternative to syngeneic mouse tumor models for the study of human immuno-oncology and have proven effective tools to test immunotherapies targeting T cells. However, human NK cell development and survival in humanized NOD-scid-IL2rgnull (NSG) mice are severely limited. To enhance NK cell development, we have developed NSG mice that constitutively expresses human Interleukin 15 (IL15), NSG-Tg(Hu-IL15). Following hematopoietic stem cell engraftment of NSG-Tg(Hu-IL15) mice, significantly higher levels of functional human CD56+ NK cells are detectable in blood and spleen, as compared to NSG mice. Hematopoietic stem cell (HSC)-engrafted NSG-Tg(Hu-IL15) mice also supported the development of human CD3+ T cells, CD20+ B cells, and CD33+ myeloid cells. Moreover, the growth kinetics of a patient-derived xenograft (PDX) melanoma were significantly delayed in HSC-engrafted NSG-Tg(Hu-IL15) mice as compared to HSC-engrafted NSG mice demonstrating that human NK cells have a key role in limiting the tumor growth. Together, these data demonstrate that HSC-engrafted NSG-Tg(Hu-IL15) mice support enhanced development of functional human NK cells, which limit the growth of PDX tumors.

Antimicrobial peptides: Defending the mucosal epithelial barrier.

The recent epidemic caused by aerosolized SARS-CoV-2 virus illustrates the importance and vulnerability of the mucosal epithelial barrier against infection. Antimicrobial proteins and peptides (AMPs) are key to the epithelial barrier, providing immunity against microbes. In primitive life forms, AMPs protect the integument and the gut against pathogenic microbes. AMPs have also evolved in humans and other mammals to enhance newer, complex innate and adaptive immunity to favor the persistence of commensals over pathogenic microbes. The canonical AMPs are helictical peptides that form lethal pores in microbial membranes. In higher life forms, this type of AMP is exemplified by the defensin family of AMPs. In epithelial tissues, defensins, and calprotectin (complex of S100A8 and S100A9) have evolved to work cooperatively. The mechanisms of action differ. Unlike defensins, calprotectin sequesters essential trace metals from microbes, which inhibits growth. This review focuses on defensins and calprotectin as AMPs that appear to work cooperatively to fortify the epithelial barrier against infection. The antimicrobial spectrum is broad with overlap between the two AMPs. In mice, experimental models highlight the contribution of both AMPs to candidiasis as a fungal infection and periodontitis resulting from bacterial dysbiosis. These AMPs appear to contribute to innate immunity in humans, protecting the commensal microflora and restricting the emergence of pathobionts and pathogens. A striking example in human innate immunity is that elevated serum calprotectin protects against neonatal sepsis. Calprotectin is also remarkable because of functional differences when localized in epithelial and neutrophil cytoplasm or released into the extracellular environment. In the cytoplasm, calprotectin appears to protect against invasive pathogens. Extracellularly, calprotectin can engage pathogen-recognition receptors to activate innate immune and proinflammatory mechanisms. In inflamed epithelial and other tissue spaces, calprotectin, DNA, and histones are released from degranulated neutrophils to form insoluble antimicrobial barriers termed neutrophil extracellular traps. Hence, calprotectin and other AMPs use several strategies to provide microbial control and stimulate innate immunity.

Pentraxin 3 Inhibits Complement-driven Macrophage Activation to Restrain Granuloma Formation in Sarcoidosis.

Rationale: Sarcoidosis is a multisystemic inflammatory disease characterized by the formation of granulomas in response to persistent stimuli. The long pentraxin PTX3 (pentraxin 3) has emerged as a component of humoral innate immunity with essential functions in the resolution of inflammation, but its role during granuloma formation is unknown. Objectives: To evaluate PTX3 as a modulator of pathogenic signals involved in granuloma formation and inflammation in sarcoidosis. Methods: Peripheral blood mononuclear cells obtained from patients with sarcoidosis harboring loss-of-function genetic variants and gene-deleted mice were used to assess the role of PTX3 in experimental models of granuloma formation invitro and invivo. The identified mechanisms of granulomatous inflammation were further evaluated in tissue and BAL samples and correlated with the disease course. Measurements and Main Results: We have identified a molecular link between PTX3 deficiency and the pathogenic amplification of complement activation to promote granuloma formation. Mechanistically, PTX3 deficiency licensed the complement component C5a-mediated activation of the metabolic checkpoint kinase mTORC1 (mammalian target of rapamycin complex 1) and the reprogramming of macrophages toward increased glycolysis to foster their proliferation and aggregation. This process sustained the further recruitment of granuloma-promoting immune cells and the associated proinflammatory microenvironment and influenced the clinical course of the disease. Conclusions: Our results identify PTX3 as a pivotal molecule that regulates complement-mediated signaling cues in macrophages to restrain granulomatous inflammation and highlight the therapeutic potential of this signaling axis in targeting granuloma formation in sarcoidosis.

9-OR: ADA Presidents' Select Abstract: m6A mRNA Methylation Regulates the Innate Immune Response in Human Beta Cells

Innate immunity is directly associated with Type 1 diabetes (T1D) . Recently, N6-methyladenosine (m6A) has been shown to modulate human β-cell biology and innate immunity. Here, we focused on the contribution of m6A in modulating T1D development. RNA-seq. in β-cells revealed downregulation of the m6A writers (Mettl3, Mettl14, and Wtap) in pre-diabetic NOD mice. Consistently, pancreases from female NOD mice and human T1D showed downregulation of METTL3 protein levels in insulin-positive cells as the disease progressed. m6A-sequencing in human T1D versus control islets and intersection with differentially expressed genes (DEGs) in T1D β-cells from a single-cell RNA seq. dataset, revealed enriched pathways associated with ER function, T1D, and apoptosis. Pro-inflammatory cytokines are directly linked to β-cell autoimmunity and are considered a useful tool to study T1D onset. We applied m6A-sequencing in cytokine-treated human islet preparations, and in parallel studies, treated EndoC-βH1 cells with cytokines followed by RNA-sequencing. Intersection of m6A-decorated and common DEGs in human islets and EndoC-βH1 cells revealed enrichment in pathways associated with the innate immune response. METTL3 silencing in EndoC-βH1 impacted several innate immune mediators upon cytokine challenge. Incubation of human islets from multiple donors with ER-stress inducers, ROS donors, NO donors, and ROS or NO scavengers revealed that pre-existing ER stress and ROS decrease METTL3, while physiological levels of NO upregulate METTL3. We conclude that ROS drives METTL3 downregulation associated with T1D. Exploring therapeutic relevance by AAV-8 mediated gene delivery showed that β-cell specific upregulation of Mettl3 leads to a decrease in hyperglycemia during early stages of T1D in female NOD mice. Together, these results demonstrate a novel layer of regulation in human β-cells in the context of T1D and point to targeting METTL3 as a therapeutic approach to promote β-cell survival and improve glycemia. Disclosure D.F.De jesus: n/a. D.L.Eizirik: None. R.Kulkarni: Advisory Panel; Biomea, Novo Nordisk, REDD Pharma, Consultant; Relay Therapeutics, Research Support; Inversago, SerPlus. Z.Zhang: Research Support; SinoVac. N.K.Brown: None. G.Basile: None. L.Xiao: None. S.Kahraman: Employee; Boehringer Ingelheim International GmbH. C.E.Mathews: None. A.C.Powers: None. M.A.Atkinson: None. Funding American Diabetes Association (7-21-PDF-140) ; R01 DK067536R01 DK103215R01 DK117639

The impact of short-term confinement on human innate immunity

During space missions cosmonauts are exposed to a myriad of distinct stressors such as radiation, overloads, weightlessness, radiation, isolation in artificial environmental conditions, which causes changes in immune system. During space flights it is very difficult to determine the particular factor associated with the observed immunological responses. This makes ground-based experiments examining the effect of each space flight associated factor along of particular value. Determining mechanisms causing alterations in cosmonauts’ immunity can lead to potential targets for different countermeasures. In the current article we present the study of the early period of adaptation of human innate immunity of 6 healthy test-subjects, 4 males and 2 females aged 25 through 40, to isolation factors (hypodynamia, psychological stress, artificial environment). We measured multiple parameters characterizing innate immunity status in blood samples at chosen time points before, during and after the mission. In the experiment, highly enhanced cytokine responses were observed upon ex vivo antigen stimulations in comparison to baseline values. For cellular parameters we found multidirectional dynamics with a persistent prevalence of increasing TLRs+ monocytes as well as TLRs expression. Our study provides evidence that even a short-term confinement leads to immune changes in healthy humans that may trigger aberrant immune response.

Raman Microspectroscopy Identifies Biochemical Activation Fingerprints in THP-1- and PBMC-Derived Macrophages.

(1) The monocytic leukemia cell line THP-1 and primary monocyte-derived macrophages (MDMs) are popular in vitro model systems to study human innate immunity, wound healing, and tissue regeneration. However, both cell types differ significantly in their origin and response to activation stimuli. (2) Resting THP-1 and MDMs were stimulated with lipopolysaccharide (LPS) and interferon γ (IFNγ) and analyzed by Raman microspectroscopy (RM) before and 48 h after activation. Raman data were subsequently analyzed using principal component analysis. (3) We were able to resolve and analyze the spatial distribution and molecular composition of proteins, nucleic acids, and lipids in resting and activated THP-1 and MDMs. Our findings reveal that proinflammatory activation-induced significant spectral alterations at protein and phospholipid levels in THP-1. In MDMs, we identified that nucleic acid and non-membrane-associated intracellular lipid composition were also affected. (4) Our results show that it is crucial to carefully choose the right cell type for an in vitro model as the nature of the cells itself may impact immune cell polarization or activation results. Moreover, we demonstrated that RM is a sensitive tool for investigating cell-specific responses to activation stimuli and monitoring molecular changes in subcellular structures.

Heat shock protein 90 is a new potential target of anti-rejection therapy in allotransplantation.

The critical roles of heat shock protein 90 (HSP90) in immune reactions associated with viral infection and autoimmune disease are well known. To date, however, its roles in the alloimmune response and the immunosuppressive effect of HSP90 inhibitors in allotransplantation have remained unknown. The purpose of this study was to examine the therapeutic efficacy of the HSP90 inhibitor 17-DMAG in allotransplantation models. C57BL/6 (H-2b) and BALB/c (H-2d) mice were used as donors for and recipients of skin and heart transplantation, respectively. Treatment with 17-DMAG (daily i.p.) or a vehicle was initiated 3days before transplantation. Immunological outcomes were assessed by histopathological examinations, flow cytometric analysis, quantitative RT-PCR, ELISA, ELISPOT assay, and MLR. 17-DMAG treatment significantly prolonged the survival of both skin and heart allografts. In 17-DMAG-treated mice, donor-reactive splenocytes producing IFN-γ were significantly reduced along with the intragraft mRNA expression level and serum concentration of IFN-γ. Intragraft mRNA expression of cytokines and chemokines associated with both innate and adaptive immunity was suppressed in 17-DMAG-treated group. MLR showed suppression of the donor-specific proliferation of CD4 + T and CD19 + B cells in the spleens of 17-DMAG-treated mice. 17-DMAG treatment also reduced the number of activated NK cells. Furthermore, the treatment lowered the titers of donor-specific antibodies in the serum and prolonged a second skin allograft in mice sensitized by previous skin transplantation. HSP90 inhibition by 17-DMAG can affect various immune responses, including innate immunity, adaptive immunity, and humoral immunity, suggesting its therapeutic potential against acute rejection in allotransplantation.

Process Engineering of Biopharmaceutical Production in Moss Bioreactors via Model-Based Description and Evaluation of Phytohormone Impact.

The moss Physcomitrella is an interesting production host for recombinant biopharmaceuticals. Here we produced MFHR1, a synthetic complement regulator which has been proposed for the treatment of diseases associated to the complement system as part of human innate immunity. We studied the impact of different operation modes for the production process in 5 L stirred-tank photobioreactors. The total amount of recombinant protein was doubled by using fed-batch or batch compared to semi-continuous operation, although the maximum specific productivity (mg MFHR1/g FW) increased just by 35%. We proposed an unstructured kinetic model which fits accurately with the experimental data in batch and semi-continuous operation under autotrophic conditions with 2% CO2 enrichment. The model is able to predict recombinant protein production, nitrate uptake and biomass growth, which is useful for process control and optimization. We investigated strategies to further increase MFHR1 production. While mixotrophic and heterotrophic conditions decreased the MFHR1-specific productivity compared to autotrophic conditions, addition of the phytohormone auxin (NAA, 10 µM) to the medium enhanced it by 470% in shaken flasks and up to 230% and 260%, in batch and fed-batch bioreactors, respectively. Supporting this finding, the auxin-synthesis inhibitor L-kynurenine (100 µM) decreased MFHR1 production significantly by 110% and 580% at day 7 and 18, respectively. Expression analysis revealed that the MFHR1 transgene, driven by the Physcomitrella actin5 (PpAct5) promoter, was upregulated 16 h after NAA addition and remained enhanced over the whole process, whereas the auxin-responsive gene PpIAA1A was upregulated within the first 2 hours, indicating that the effect of auxin on PpAct5 promoter-driven expression is indirect. Furthermore, the day of NAA supplementation was crucial, leading to an up to 8-fold increase of MFHR1-specific productivity (0.82 mg MFHR1/g fresh weight, 150 mg accumulated over 7 days) compared to the productivity reported previously. Our findings are likely to be applicable to other plant-based expression systems to increase biopharmaceutical production and yields.

Synthetic Antibiotic Derived from Sequences Encrypted in a Protein from Human Plasma.

Encrypted peptides have been recently found in the human proteome and represent a potential class of antibiotics. Here we report three peptides derived from the human apolipoprotein B (residues 887-922) that exhibited potent antimicrobial activity against drug-resistant Klebsiella pneumoniae, Acinetobacter baumannii, and Staphylococci both in vitro and in an animal model. The peptides had excellent cytotoxicity profiles, targeted bacteria by depolarizing and permeabilizing their cytoplasmic membrane, inhibited biofilms, and displayed anti-inflammatory properties. Importantly, the peptides, when used in combination, potentiated the activity of conventional antibiotics against bacteria and did not select for bacterial resistance. To ensure translatability of these molecules, a protease resistant retro-inverso variant of the lead encrypted peptide was synthesized and demonstrated anti-infective activity in a preclinical mouse model. Our results provide a link between human plasma and innate immunity and point to the blood as a source of much-needed antimicrobials.

Recognition and inhibition of SARS-CoV-2 by humoral innate immunity pattern recognition molecules.

The humoral arm of innate immunity includes diverse molecules with antibody-like functions, some of which serve as disease severity biomarkers in coronavirus disease 2019 (COVID-19). The present study was designed to conduct a systematic investigation of the interaction of human humoral fluid-phase pattern recognition molecules (PRMs) with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Of 12 PRMs tested, the long pentraxin 3 (PTX3) and mannose-binding lectin (MBL) bound the viral nucleocapsid and spike proteins, respectively. MBL bound trimeric spike protein, including that of variants of concern (VoC), in a glycan-dependent manner and inhibited SARS-CoV-2 in three in vitro models. Moreover, after binding to spike protein, MBL activated the lectin pathway of complement activation. Based on retention of glycosylation sites and modeling, MBL was predicted to recognize the Omicron VoC. Genetic polymorphisms at the MBL2 locus were associated with disease severity. These results suggest that selected humoral fluid-phase PRMs can play an important role in resistance to, and pathogenesis of, COVID-19, a finding with translational implications.

MxA: a broadly acting effector of interferon-induced human innate immunity

The Human MxA protein belongs to the dynamin superfamily of large GTPases and plays a vital role in human immunity against a broad spectrum of viruses. Evasion from MxA restriction accounts for the zoonotic transmission of many pathogenic viruses. In addition to its antiviral activity, MxA has also been implicated as an inhibitor against tumor cell motility and invasion. Over the past few decades, many advances have been made in elucidating the molecular mechanisms of MxA-mediated autoimmunity, including the determination of MxA structures at high resolutions. Together, they provide exciting insights into the antiviral function of MxA, laying a solid foundation for antiviral drug development and pandemic virus infection control, and also shed light on the development of novel approaches for the prevention and treatment against cancer metastasis.