Purification of human immunoglobulin G autoantibodies to tumor necrosis factor using affinity chromatography and magnetic separation

Hot Spots and Trends in the Relationship between Cancer and Obesity: A Systematic Review and Knowledge Graph Analysis

Cancer is one of the most difficult medical problems in today's world. There are many factors that induce cancer in humans, and obesity has become an important factor in inducing cancer. This study systematically and quantitatively describes the development trend, current situation and research hotspot of the relationship between cancer and obesity by using document statistics and knowledge graph visualization technology. Through the visualization technology analysis of knowledge graph in this study, the research hotspot and knowledge base source of the relationship between cancer and obesity in the last 20 years have been ascertained. Obesity-related factors, such as immunity, insulin, adiponectin, adipocytokines, nonalcoholic fatty liver and inflammatory reaction, may affect the occurrence of obesity and increase the risk of cancer. Obesity-related cancers include respiratory cancer, colorectal cancer, hepatocellular cancer, prostate cancer, gastric cancer, etc. Our research provides direction and basis for future research in this field, as well as technical and knowledge basis support for experts and researchers in related medical fields.

Immune Complex Formation Is Associated With Loss of Tolerance and an Antibody Response to Both Drug and Target

AMG 966 is a bi-specific, heteroimmunoglobulin molecule that binds both tumor necrosis factor alpha (TNFα) and TNF-like ligand 1A (TL1A). In a first-in-human clinical study in healthy volunteers, AMG 966 elicited anti-drug antibodies (ADA) in 53 of 54 subjects (98.1%), despite a paucity of T cell epitopes observed in T cell assays. ADA were neutralizing and bound to all domains of AMG 966. Development of ADA correlated with loss of exposure. In vitro studies demonstrated that at certain drug-to-target ratios, AMG 966 forms large immune complexes with TNFα and TL1A, partially restoring the ability of the aglycosylated Fc domain to bind FcγRIa and FcγRIIa, leading to the formation of ADA. In addition to ADA against AMG 966, antibodies to endogenous TNFα were also detected in the sera of subjects dosed with AMG 966. This suggests that the formation of immune complexes between a therapeutic and target can cause loss of tolerance and elicit an antibody response against the target.

Production of pure fractions of immunoglobulin G subclass autoantibodies against tumor necrosis factor

Autoantibodies directed against cytokines are important effector molecules regulating the biological activity of cytokines. There is experimental evidence indicating that autoantibodies belonging to different immunoglobulin G (IgG) subclasses may have different functional activity. The purpose of this work was to develop a protocol for the purification of fractions of IgG subclass antibodies directed against tumor necrosis factor (TNF). We developed a series of steps, including gel filtration, positive and negative affinity chromatography, and ultrafiltration, to achieve this goal. Our protocol purified IgG subclass autoantibodies directed against TNF from a human immunoglobulin preparation. The isolation of these anti-TNF autoantibodies will enable evaluation of the effect of TNF-specific antibodies on TNF biological activity. Our newly developed technique for purifying subclasses of anti-TNF autoantibodies may be important for both basic research on the functional activity of these autoantibodies and for clinical immunology.

Levels of TNF, TNF autoantibodies and soluble TNF receptors in patients with bronchial asthma

OBJECTIVES

The aim of the study was to evaluate the potential contribution made by tumor necrosis factor (TNF) autoantibodies to the pathogenesis of bronchial asthma (BA).

METHODS

We used affinity chromatography methods and a magnetic separation procedure to purify human autoantibodies specific to TNF. The autoantibodies were used as a calibration material to determine the absolute content of autoantibodies to TNF using enzyme-linked immunosorbent assay (ELISA). TNF content and levels of soluble receptors to TNF were determined using the ELISA commercial test kits.

RESULTS

We demonstrated significant increases in the levels of TNF and soluble TNF receptors in the sera of patients with uncontrolled and controlled BA, as compared with healthy donors. Levels of autoantibodies of the IgG2 and IgG4 subclasses were significantly higher in sera from patients with uncontrolled BA than in healthy donors. Levels of IgG2 autoantibodies were significantly higher in sera from patients with uncontrolled BA than in patients with controlled BA.

CONCLUSIONS

BA is associated with changes in the levels of not only TNF and soluble receptors for TNF, but also autoantibodies to TNF. Given the magnitude of the changes in the levels of different subclasses of autoantibodies to TNF, we propose that these autoantibodies might contribute to the pathogenesis of BA.