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Journal of Biotechnology Aug 2024Antigen-presenting cells (APCs) play an important role in virus infection control by bridging innate and adaptive immune responses. Macrophages and dendritic cells (DCs)...
Antigen-presenting cells (APCs) play an important role in virus infection control by bridging innate and adaptive immune responses. Macrophages and dendritic cells (DCs) possess various surface receptors to recognize/internalize antigens, and antibody binding can enhance pathogen-opsonizing uptake by these APCs via interaction of antibody fragment crystallizable (Fc) domains with Fc receptors, evoking profound pathogen control in certain settings. Here, we examined phagocytosis-enhancing potential of Fc domains directly oriented on a retroviral virion/virus-like particle (VLP) surface. We generated an expression vector coding a murine Fc fragment fused to the transmembrane region (TM) of a retroviral envelope protein, deriving expression of the Fc-TM fusion protein on the transfected cell surface and production of virions incorporating the chimeric Fc upon co-transfection. Incubation of Fc-displaying simian immunodeficiency virus (SIV) with murine J774 macrophages and bone marrow-derived DCs derived Fc receptor-dependent enhanced uptake, being visualized by imaging cytometry. Alternative preparation of a murine leukemia virus (MLV) backbone-based Fc-displaying VLP loading an influenza virus hemagglutinin (HA) antigen resulted in enhanced HA internalization by macrophages, stating antigen compatibility of the design. Results show that the Fc-TM fusion molecule can be displayed on certain viruses/VLPs and may be utilized as a molecular adjuvant to facilitate APC antigen uptake.
Topics: Animals; Mice; Immunoglobulin Fc Fragments; Antigen-Presenting Cells; Virion; Dendritic Cells; Macrophages; Recombinant Fusion Proteins; Simian Immunodeficiency Virus; Hemagglutinin Glycoproteins, Influenza Virus; Cell Line; Leukemia Virus, Murine; Phagocytosis; Humans
PubMed: 38851397
DOI: 10.1016/j.jbiotec.2024.06.004 -
Microbes and Infection Jun 2024Neutrophils constitute the primary defense against bacterial infections, yet certain pathogens express virulence factors that enable them to subvert neutrophils-mediated...
Neutrophils constitute the primary defense against bacterial infections, yet certain pathogens express virulence factors that enable them to subvert neutrophils-mediated killing. Outer membrane vesicles (OMVs) have emerged as a secretory system through which bacteria deliver virulence factors to host cells. OMVs from Bordetella pertussis, the etiological agent of whooping cough, are loaded with most of bacterial virulence factors, including CyaA, which plays a key role in B. pertussis evasion of neutrophils bactericidal activity. In our study, we investigated the role of B. pertussis OMVs in bacterial interaction with neutrophils. We observed that interaction of OMVs with neutrophils led to a decrease in the expression of cell surface CR3 and FcγRs, an effect dependent on the CyaA toxin delivered by these vesicles. This decreased receptor expression led to reduced bacterial uptake by neutrophils, irrespective of the presence of opsonic antibodies. Moreover, CyaA delivered by OMVs hindered intracellular bactericidal trafficking, promoting bacterial intracellular survival. When both bacteria and OMVs were opsonized, competition between opsonized OMVs and B. pertussis for FcγRs on neutrophils led to a significant decrease in bacterial uptake. Overall, our findings suggest that B. pertussis OMVs promote bacterial survival to the encounter with neutrophils in both naïve and immunized individuals.
PubMed: 38849071
DOI: 10.1016/j.micinf.2024.105375 -
Science Advances Jun 2024Immunotoxicity remains a major hindrance to chemotherapy in cancer therapy. Nanocarriers may alleviate the immunotoxicity, but the optimal design remains unclear. Here,...
Immunotoxicity remains a major hindrance to chemotherapy in cancer therapy. Nanocarriers may alleviate the immunotoxicity, but the optimal design remains unclear. Here, we created two variants of maytansine (DM1)-loaded synthetic high-density lipoproteins (D-sHDL) with either physically entrapped (D-sHDL) or chemically conjugated (D-sHDL) DM1. We found that D-sHDL showed less accumulation in the tumor draining lymph nodes (DLNs) and femur, resulting in a lower toxicity against myeloid cells than D-sHDL via avoiding scavenger receptor class B type 1 (SR-B1)-mediated DM1 transportation into the granulocyte-monocyte progenitors and dendritic cells. Therefore, higher densities of lymphocytes in the tumors, DLNs, and blood were recorded in mice receiving D-sHDL, leading to a better efficacy and immune memory of D-sHDL against colon cancer. Furthermore, liposomes with conjugated DM1 (D-Lipo) showed lower immunotoxicity than those with entrapped drug (D-Lipo) through the same mechanism after apolipoprotein opsonization. Our findings highlight the critical role of drug loading patterns in dictating the biological fate and activity of nanomedicine.
Topics: Animals; Nanoparticles; Mice; Cell Line, Tumor; Humans; Scavenger Receptors, Class B; Antineoplastic Agents; Lipoproteins, HDL; Drug Carriers; Colonic Neoplasms; Liposomes; Lipids
PubMed: 38838152
DOI: 10.1126/sciadv.adk9996 -
Frontiers in Immunology 2024Innate immunity is crucial to reducing parasite burden and contributing to survival in severe malaria. Monocytes are key actors in the innate response and, like...
INTRODUCTION
Innate immunity is crucial to reducing parasite burden and contributing to survival in severe malaria. Monocytes are key actors in the innate response and, like macrophages, are plastic cells whose function and phenotype are regulated by the signals from the microenvironment. In the context of cerebral malaria (CM), monocyte response constitutes an important issue to understand. We previously demonstrated that decreased percentages of nonclassical monocytes were associated with death outcomes in CM children. In the current study, we postulated that monocyte phagocytosis function is impacted by the severity of malaria infection.
METHODS
To study this hypothesis, we compared the opsonic and nonopsonic phagocytosis capacity of circulant monocytes from Beninese children with uncomplicated malaria (UM) and CM. For the CM group, samples were obtained at inclusion (D0) and 3 and 30 days after treatment (D3, D30). The phagocytosis capacity of monocytes and their subsets was characterized by flow cytometry and transcriptional profiling by studying genes known for their functional implication in infected-red blood cell (iRBC) elimination or immune escape.
RESULTS
Our results confirm our hypothesis and highlight the higher capacity of nonclassical monocytes to phagocyte iRBC. We also confirm that a low number of nonclassical monocytes is associated with CM outcome when compared to UM, suggesting a mobilization of this subpopulation to the cerebral inflammatory site. Finally, our results suggest the implication of the inhibitory receptors LILRB1, LILRB2, and Tim3 in phagocytosis control.
DISCUSSION
Taken together, these data provide a better understanding of the interplay between monocytes and malaria infection in the pathogenicity of CM.
Topics: Humans; Malaria, Cerebral; Phagocytosis; Monocytes; Male; Child, Preschool; Female; Child; Infant; Plasmodium falciparum; Opsonin Proteins; Erythrocytes; Immunity, Innate
PubMed: 38835780
DOI: 10.3389/fimmu.2024.1358853 -
Journal of Leukocyte Biology Jun 2024
PubMed: 38829387
DOI: 10.1093/jleuko/qiae119 -
Assay and Drug Development Technologies Jun 2024Nanoparticle-based drug delivery systems have emerged as promising platforms for enhancing therapeutic efficacy while minimizing off-target effects. Among various... (Review)
Review
Nanoparticle-based drug delivery systems have emerged as promising platforms for enhancing therapeutic efficacy while minimizing off-target effects. Among various strategies employed to optimize these systems, polyethylene glycol (PEG) modification, known as PEGylation-the covalent attachment of PEG to nanoparticles, has gained considerable attention for its ability to impart stealth properties to nanoparticles while also extending circulation time and improving biocompatibility. PEGylation extends to different drug delivery systems, in specific, nanoparticles for targeting cancer cells, where the concentration of drug in the cancer cells is improved by virtue of PEGylation. The primary challenge linked to PEGylation lies in its confirmation. Numerous research findings provide comprehensive insights into selecting PEG for various PEGylation methods. In this review, we have endeavored to consolidate the outcomes concerning the choice of PEG and diverse PEGylation techniques.
PubMed: 38828531
DOI: 10.1089/adt.2024.015 -
ACS Infectious Diseases Jun 2024is a fungus classified by the World Health Organization as a critically important pathogen, which poses a significant threat to immunocompromised individuals. In this...
is a fungus classified by the World Health Organization as a critically important pathogen, which poses a significant threat to immunocompromised individuals. In this study, we present the chemical synthesis and evaluation of two semisynthetic vaccine candidates targeting the capsular polysaccharide glucuronoxylomannan (GXM) of . These semisynthetic glycoconjugate vaccines contain an identical synthetic decasaccharide (M2 motif) antigen. This antigen is present in serotype A strains, which constitute 95% of the clinical cryptococcosis cases. This synthetic oligosaccharide was conjugated to two proteins (CRM197 and Anthrax 63 kDa PA) and tested for immunogenicity in mice. The conjugates elicited a specific antibody response that bound to the M2 motif but also exhibited additional cross-reactivity toward M1 and M4 GXM motifs. Both glycoconjugates produced antibodies that bound to GXM in ELISA assays and to live fungal cells. Mice immunized with the CRM197 glycoconjugate produced weakly opsonic antibodies and displayed trends toward increased median survival relative to mice given a mock PBS injection (18 vs 15 days, = 0.06). These findings indicate promise, achieving a successful vaccine demands further optimization of the glycoconjugate. This antigen could serve as a component in a multivalent GXM motif vaccine.
Topics: Cryptococcus neoformans; Animals; Fungal Vaccines; Mice; Cryptococcosis; Glycoconjugates; Vaccines, Conjugate; Antibodies, Fungal; Female; Polysaccharides; Mice, Inbred BALB C; Bacterial Proteins; Antigens, Fungal
PubMed: 38819951
DOI: 10.1021/acsinfecdis.4c00094 -
Frontiers in Bioscience (Landmark... May 2024Recent studies highlighted the presence of anti-α-Gal antibodies in patients implanted with commercial bioprosthetic heart valves (BHVs). BHVs expose residual α-Gal...
BACKGROUND
Recent studies highlighted the presence of anti-α-Gal antibodies in patients implanted with commercial bioprosthetic heart valves (BHVs). BHVs expose residual α-Gal xenoantigen and their recognition by the circulating anti-Gal antibodies leads to opsonization of the device's tissue component with the consequent triggering of a deterioration pathway that culminates with calcification. Small animal models such as mice and rats have been broadly involved in the testing of biomaterials by subcutaneous implantation, especially for the effectiveness of BHVs anti-calcific treatments. However, since models employed for this purpose express α-Gal antigen, the implantation of BHVs' leaflets does not elicit a proper immunological response, so the calcification propensity may be dramatically underestimated.
METHODS
An α-Gal knockout (KO) mouse model has been created, using the CRISP/Cas9 approach, and adopted to assess the calcification potential of commercial BHVs leaflets through the surgical implantation in the back subcutis area. Calcium quantification was performed by inductively coupled plasma analysis; immune response against the BHVs leaflets and α-Gal silencing was evaluated through immunological assays.
RESULTS
Two months after the implantation of commercial BHV leaflets, the anti-Gal antibody titers in KO mice doubled when compared with those found in wild-type (WT) ones. Leaflets explanted from KO mice, after one month, showed a four-time increased calcium deposition concerning the ones explanted from WT. The degree of silencing of α-Gal varied, depending on the specific organ that was assessed. In any case, the animal model was suitable for evaluating implanted tissue responses.
CONCLUSIONS
Such mouse model proved to be an accurate tool for the study of the calcific propensity of commercial BHVs leaflets than those hitherto used. Given its reliability, it could also be successfully used to study even other diseases in which the possible involvement of α-Gal has been observed.
Topics: Animals; Heart Valve Prosthesis; Calcinosis; Mice, Knockout; Bioprosthesis; Mice; Disease Models, Animal; Mice, Inbred C57BL; Male
PubMed: 38812319
DOI: 10.31083/j.fbl2905181 -
EBioMedicine Jun 2024Natural killer (NK) cells are important innate immunity players and have unique abilities to recognize and eliminate cancer cells, particularly in settings of...
BACKGROUND
Natural killer (NK) cells are important innate immunity players and have unique abilities to recognize and eliminate cancer cells, particularly in settings of antibody-opsonization and antibody-dependant cellular cytotoxicity (ADCC). However, NK cell-based responses in bladder cancers to therapeutic antibodies are typically immunosuppressed, and these immunosuppressive mechanisms are largely unknown.
METHODS
Single cell RNA sequencing (scRNA-seq) and high-dimensional flow cytometry were used to investigate the phenotype of tumour-infiltrating NK cells in patients with bladder cancer. Further, in vitro, and in vivo models of this disease were used to validate these findings.
FINDINGS
NK cells within bladder tumours displayed reduced expression of FcγRIIIa/CD16, the critical Fc receptor involved in ADCC-mediated cytotoxicity, on both transcriptional and protein levels. Transcriptional signatures of transforming growth factor (TGF)-β-signalling, a pleiotropic cytokine known for its immunosuppressive and tissue residency-inducing effects, were upregulated in tumour-infiltrating NK cells. TGF-β mediated CD16 downregulation on NK cells, was further validated in vitro, which was accompanied by a transition into a tissue residency phenotype. This CD16 downregulation was also abrogated by TGF-βR signalling inhibition, which could also restore the ADCC ability of NK cells subject to TGF-β effects. In a humanized mouse model of bladder cancer, mice treated with a TGF-β inhibitor exhibited increased ADCC activity compared to mice treated only with antibodies.
INTERPRETATION
This study highlights how TGF-β-rich bladder cancers inhibit NK cell-mediated ADCC by downregulating CD16. TGF-β inhibition represents new avenues to reverse immunosuppression and enhance the tumoricidal capacity of NK cells in bladder cancer.
FUNDING
The Guimaraes Laboratory is funded by a US Department of Defense-Breast Cancer Research Program-Breakthrough Award Level 1 (#BC200025), a grant (#2019485) awarded through the Medical Research Future Fund (MRFF, with the support of the Queensland Children's Hospital Foundation, Microba Life Sciences, Richie's Rainbow Foundation, Translational Research Institute (TRI) and UQ), and a grant (#RSS_2023_085) funded by a Metro South Health Research Support Scheme. J.K.M.W. is funded by a UQ Research Training Program PhD Scholarship and N.O. is funded by a NHMRC Postgraduate Scholarship (#2021932).
Topics: Killer Cells, Natural; Urinary Bladder Neoplasms; Humans; Animals; Signal Transduction; Mice; Transforming Growth Factor beta; Receptors, IgG; Antibody-Dependent Cell Cytotoxicity; Cell Line, Tumor; Disease Models, Animal; GPI-Linked Proteins; Lymphocytes, Tumor-Infiltrating; Gene Expression Regulation, Neoplastic; Single-Cell Analysis; Female
PubMed: 38810560
DOI: 10.1016/j.ebiom.2024.105176 -
Journal, Genetic Engineering &... Jun 2024Malaria has remained a major health concern for decades among people living in tropical and sub-tropical countries. Plasmodium falciparum is one of the critical species...
BACKGROUND
Malaria has remained a major health concern for decades among people living in tropical and sub-tropical countries. Plasmodium falciparum is one of the critical species that cause severe malaria and is responsible for major mortality. Moreover, the parasite has generated resistance against all WHO recommended drugs and therapies. Therefore, there is an urgent need for preventive measures in the form of reliable vaccines to achieve the target of a malaria-free world. Surface proteins are the preferable choice for subunit vaccine development because they are rapidly detected and engaged by host immune cells and vaccination-induced antibodies. Additionally, abundant surface or membrane proteins may contribute to the opsonization of pathogens by vaccine-induced antibodies.
RESULTS
In our study, we have listed all those surface proteins from the literature that could be functionally important and essential for infection and immune evasion of the malaria parasite. Eight Plasmodium surface and membrane proteins from the pre-erythrocyte and erythrocyte stages were shortlisted. Thirty-seven epitopes (B-cell, CTL, and HTL epitopes) from these proteins were predicted using immune-informatic tools and joined with suitable peptide linkers to design a vaccine construct. A TLR-4 agonist peptide adjuvant was added at the N-terminus of the multi-epitope series, followed by the PADRE sequence and EAAAK linker. The TLR-4 receptor was docked with the construct's anticipated model structure. The complex of vaccine and TLR-4, with the lowest energy -1514, was found to be stable under simulated physiological settings.
CONCLUSION
This study has provided a novel multi-epitope construct that may be exploited further for the development of an efficient vaccine for malaria.
PubMed: 38797552
DOI: 10.1016/j.jgeb.2024.100377