Search results for "Complement system"

Protein corona–mediated targeting of nanocarriers to B cells allows redirection of allergic immune responses

2018

Background Nanoparticle (NP)–based vaccines are attractive immunotherapy tools because of their capability to codeliver antigen and adjuvant to antigen-presenting cells. Their cellular distribution and serum protein interaction ("protein corona") after systemic administration and their effect on the functional properties of NPs is poorly understood. Objectives We analyzed the relevance of the protein corona on cell type–selective uptake of dextran-coated NPs and determined the outcome of vaccination with NPs that codeliver antigen and adjuvant in disease models of allergy. Methods The role of protein corona constituents for cellular binding/uptake of dextran-coated ferrous nanoparticles (DE…

CD38-Specific Biparatopic Heavy Chain Antibodies Display Potent Complement-Dependent Cytotoxicity Against Multiple Myeloma Cells

2018

CD38 is overexpressed by multiple myeloma cells and has emerged as a target for therapeutic antibodies. Nanobodies are soluble single domain antibody fragments derived from the VHH variable domain of heavy chain antibodies naturally occurring in camelids. We previously identified distinct llama nanobodies that recognize three non-overlapping epitopes of the extracellular domain of CD38. Here, we fused these VHH domains to the hinge, CH2, and CH3 domains of human IgG1, yielding highly soluble chimeric llama/human heavy chain antibodies (hcAbs). We analyzed the capacity of these hcAbs to mediate complement-dependent cytotoxicity (CDC) to CD38-expressing human multiple myeloma and Burkitt lymp…

Anti-Tumor Necrosis Factor α Therapeutics Differentially Affect Leishmania Infection of Human Macrophages

2018

Tumor necrosis factor α (TNFα) drives the pathophysiology of human autoimmune diseases and consequently, neutralizing antibodies (Abs) or Ab-derived molecules directed against TNFα are essential therapeutics. As treatment with several TNFα blockers has been reported to entail a higher risk of infectious diseases such as leishmaniasis, we established an in vitro model based on Leishmania-infected human macrophages, co-cultured with autologous T-cells, for the analysis and comparison of anti-TNFα therapeutics. We demonstrate that neutralization of soluble TNFα (sTNFα) by the anti-TNFα Abs Humira®, Remicade®, and its biosimilar Remsima® negatively affects infection as treatment with these agen…

Membrane Attack Complex in Myocardial Ischemia/Reperfusion Injury: A Systematic Review for Post Mortem Applications

2020

The complement system has a significant role in myocardial ischemia/reperfusion injury, being responsible for cell lysis and amplification of inflammatory response. In this context, several studies highlight that terminal complement complex C5b-9, also known as the membrane attack complex (MAC), is a significant contributor. The MAC functions were studied by many researchers analyzing the characteristics of its activation in myocardial infarction. Here, a systematic literature review was reported to evaluate the principal features, advantages, and limits (regarding the application) of complement components and MAC in post mortem settings to perform the diagnosis of myocardial ischemia/infar…

Gradual complement protein adsorption and macrophage polarization: inflammation & dental implants

2020

Expression of properdin in human monocytes

1994

Properdin is the only known positive regulator of the alternative pathway of complement activation. Northern blot analysis of cell lines derived from fibroblasts, B-cells, hepatoma cells, and cells of the monocyte-macrophage lineage revealed properdin expression only in the myelomonocytic cell line HL-60, in the monoblastic cell line U-937 and in the monocytic line Mono Mac 6. Culture of Mono Mac 6 cells for 24 h with phorbol 12-myristate 13-acetate, bacterial lipopolysaccharide and the cytokines interleukin-1 beta and tumour necrosis factor-alpha enhanced mRNA abundance, with the strongest effect (tenfold) being observed with the lipopolysaccharide. In contrast, recombinant interferon-gamm…

The impact of two whole blood inline filters on markers of coagulation, complement and cell activation

2005

Background and Objectives  There exists a current lack of information about the impact of different inline filters, used for the leucoreduction of whole blood (WB), on the levels of clotting factors and markers of coagulation, complement and cell activation in plasma. Only a few small comparisons of different types of WB inline filters have been published to date. Materials and Methods  This study compared two plasma types of 200 units each. Both study groups were derived from WB, inline-filtered and held for 2 h at 20° between donation and filtration. Then, 200 units (Group A) were filtered using a positively charged polyester filter (Baxter RZ2000) and the other 200 units (Group B) were f…

C4, BF, C3 Allele Distribution and Complement Activity in Healthy Aged People and Centenarians

1999

The aim of this study was to examine the complement system and the distribution of some human leukocyte antigen (HLA) class III alleles (C4, BF) in healthy aged people (77 centenarians and 89 elderly subjects). We have also studied the alleles of C3, a complement component genetically unrelated to HLA, the immunochemical levels of C4 and C3 and serum functional hemolytic activity for classical (CH50) and alternative (AP50) complement pathway. The levels of C3 and C4 and the CH50 and AP50 were found to be within the normal range. The frequencies of C3, BF, and C4A alleles were similar in the cohorts that have been studied. For C4B null allele (C4BQ0) a trend toward an increase in the older c…

C4A deficiency and nonresponse to hepatitis B vaccination

2002

Hepatitis B vaccination failure has been linked to the presence of certain human leukocyte antigen class II alleles. However, the functional background of these associations has remained unclear. Complement component C 4 is encoded within the major histocompatibility complex and is essential for classical pathway activation.Healthy individuals (n=4269) were vaccinated in a prospective trial with Engerix B. Nonresponse was classified as anti-HBs10 U/l after the last vaccination. Seventy-three nonresponders (NR) (1.7%) were identified. For comparison 53 responders (R) (anti-HBs10 IU/l) were drawn randomly from the same cohort. C4 allotyping was carried out by high-voltage agarose gel electrop…

Modification of Peripheral Blood T-Lymphocyte Surface Receptors and Langerhans Cell Numbers in Hereditary Angioedema

1986

Hereditary angioedema (HAE) is a disease related to a complement disorder, namely a deficiency of C1 esterase inhibitor. Complement-split products are implicated in the regulation of the immune response, and we have compared some immunologic parameters between HAE and normal individuals. T-lymphocytes with receptors for IgG were increased in HAE, but no difference in T-cell suppressor activity for B-cells was detected. Furthermore, increased IgG receptor expression was not accompanied by any significant changes in the ratios of OKT4- and OKT8-defined antigens. Numbers of peripheral mononuclear cells (MNC) detected by alpha-naphthyl acetate esterase (ANAE) staining positivity were not signif…