Microglia play an important role in receptor-mediated phagocytosis in the CNS. In brain abscess and other CNS infections, invading bacteria undergo opsonization with Igs or complement. Microglia recognize these opsonized pathogens by Fc or complement receptors triggering phagocytosis. In this study, we investigated the role of Fcα/μR, the less-studied receptor for IgM and IgA, in microglial phagocytosis. We showed that primary microglia, as well as N9 microglial cells, express Fcα/μR. We also showed that anti-Staphylococcus aureus IgM markedly increased the rate of microglial S. aureus phagocytosis. To unequivocally test the role of Fcα/μR in IgM-mediated phagocytosis, we performed experiments in microglia from Fcα/μR(-/-) mice. Surprisingly, we found that IgM-dependent phagocytosis of S. aureus was similar in microglia derived from wild-type or Fcα/μR(-/-) mice. We hypothesized that IgM-dependent activation of complement receptors might contribute to the IgM-mediated increase in phagocytosis. To test this, we used immunologic and genetic inactivation of complement receptor 3 components (CD11b and CD18) as well as C3. IgM-, but not IgG-mediated phagocytosis of S. aureus was reduced in wild-type microglia and macrophages following preincubation with an anti-CD11b blocking Ab. IgM-dependent phagocytosis of S. aureus was also reduced in microglia derived from CD18(-/-) and C3(-/-) mice. Taken together, our findings implicate complement receptor 3 and C3, but not Fcα/μR, in IgM-mediated phagocytosis of S. aureus by microglia.
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http://dx.doi.org/10.4049/jimmunol.1401195 | DOI Listing |
J Mater Sci Mater Med
January 2025
Department of Biomaterials, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
Implants aim to restore skeletal dysfunction associated with ageing and trauma, yet infection and ineffective immune responses can lead to failure. This project characterized the microbiological and host cell responses to titanium alloy with or without electroplated metallic copper. Bacterial viability counting and scanning electron microscopy quantified and visualized the direct and indirect bactericidal effects of the Cu-electroplated titanium (Cu-Ep-Ti) against two different Staphylococcus aureus strains.
View Article and Find Full Text PDFVirulence
December 2025
Department of Biotherapy, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China.
The resistance of commonly used clinical antibiotics, such as daptomycin (DAP), has become increasingly serious in the fight against () infection. It is essential to explore key pathogenicity-driven genes/proteins in bacterial infection and antibiotics resistance, which contributes to develop novel therapeutic strategies against infections. The gene of , encoding 5'-nucleotidase (NT5), is nearly unknown for its function in drug resistance and bacterial infection.
View Article and Find Full Text PDFRes Vet Sci
January 2025
Department of Veterinary Medicine and Animal Sciences (DIVAS), University of Milan, Via dell'Università 6, 2600 Lodi, Italy.
Enniatins (ENNs) affect human and animal health. Different ENN analogs have been identified, but Enniatin B (ENN B) is the most detected in foods and feeds. This study investigated the effect of ENN B on bovine polymorphonuclear leukocytes (PMNs) challenged with increasing ENN B concentrations (0.
View Article and Find Full Text PDFBiomedica
December 2024
Laboratorio de Inmunodeficiencias, Instituto Nacional de Pediatría, Ciudad de México, México.
Introduction: Chronic granulomatous disease is a defect in phagocytosis due to deficiency of gp91phox, p22phox, p47phox, p40phox, and p67phox (classic form of the disease). Recently, EROS and p40phox deficiency were described as responsible for the non-classical form of the disease. The 1,2,3-dihydrorhodamine oxidation technique, with phorbol-12-myristate-13-acetate as a stimulus, is performed to diagnose the classic chronic granulomatous disease.
View Article and Find Full Text PDFInt J Biol Macromol
January 2025
Division of Infectious Diseases and Immunology, Department of Microbiology, School of Medicine, Iwate Medical University, 1-1-1 Idaidori, Yahaba, Iwate 028-3694, Japan. Electronic address:
Chitinase plays a role in mammalian immune responses, particularly in the degradation of fungal cell walls. The aim of the present study was to express and characterize recombinant mouse chitotriosidase (Chit1) and acidic mammalian chitinase (AMCase) without the ZZ domain, a domain that may interfere with immunological analyses. We successfully expressed recombinant chitinases without the ZZ domain (Chit1-V5-His and AMCase-V5-His) as a soluble protein from an expression vector pET21a in the Escherichia coli Rosetta-gami B (DE3) strain.
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