Anti-mosquito antibodies decrease the reproductive capacity of Aedes aegypti

Aedes aegypti (L.) fed on rabbits immunized with mosquito antigens showed a reduction in fecundity in the first oviposition and decreased viability of the progeny. Feeding behaviour of mosquitoes was not affected and no significant mortality was observed due to the presence of anti-mosquito antibodies in the bloodmeal. Antibodies were detected in the oocytes of mosquitoes 48 h after the bloodmeal. The role of specific antibodies in influencing fecundity is discussed.     

Observations of a set of isomeric anti-lactose antibodies directed against a group D streptococcal polysaccharide

Sets of isomeric anti-lactose antibodies with specificity for the lactose units of a cell wall polysaccharide fromStreptococcus faecalis strain N were induced in rabbits immunized with a vaccine of nonviable cells of the organism. Such sets of anti-lactose antibodies were isolated from the serum of immunized animals by affinity chromatography on lactosyl-Sepharose. Gel electrofocusing experiments showed that the preparations consisted of multiprotein components. One preparation of antibodies of 13 isomers was separated into homogeneous components by liquid isoelectrofocusing. The individual isomeric antibodies exhibit specificity for the lactose units of the antigenic polysaccharide, possess isoelectric points in the range of 5.9–8.0, and belong to the IgG class of immunoglobulins, and each member yields one light chain and one heavy chain on dissociation in sodium dodecyl sulfate (SDS) and mercaptoethanol. These results have been interpreted as evidence for the assembly of the chains of isomeric antibodies by a single-chain pairing mechanism.     

Drugs derived from phage display: From candidate identification to clinical practice

Phage display, one of today’s fundamental drug discovery technologies, allows identification of a broad range of biological drugs, including peptides, antibodies and other proteins, with the ability to tailor critical characteristics such as potency, specificity and cross-species binding. Further, unlike in vivo technologies, generating phage display-derived antibodies is not restricted by immunological tolerance. Although more than 20 phage display-derived antibody and peptides are currently in late-stage clinical trials or approved, there is little literature addressing the specific challenges and successes in the clinical development of phage-derived drugs. This review uses case studies, from candidate identification through clinical development, to illustrate the utility of phage display as a drug discovery tool, and offers a perspective for future developments of phage display technology.     

Mining the human autoantibody repertoire: Isolation of potent IL17A-neutralizing monoclonal antibodies from a patient with thymoma

Anti-cytokine autoantibodies have been widely reported to be present in human plasma, both in healthy subjects and in patients with underlying autoimmune conditions, such as autoimmune polyendocrinopathy candidiasis ectodermal dystrophy (APECED) or thymic epithelial neoplasms. While often asymptomatic, they can cause or facilitate a wide range of diseases including opportunistic infections. The potential therapeutic value of specific neutralizing anti-cytokine autoantibodies has not been thoroughly investigated. Here we used mammalian cell display to isolate IL17A-specific antibodies from a thymoma patient with proven high-titer autoantibodies against the same. We identified 3 distinct clonotypes that efficiently neutralized IL17A in a cell-based in vitro assay. Their potencies were comparable to those of known neutralizing antibodies, including 2, AIN457 (secukinumab) and ixekizumab that are currently in clinical development for the treatment of various inflammatory disorders. These data clearly demonstrate that the human autoantibody repertoire can be mined for antibodies with high therapeutic potential for clinical development.     

Improvement of Intracellular Traffic System by Overexpression of KDEL Receptor 1 in Antibody‐Producing CHO Cells

The localization of soluble endoplasmic reticulum (ER) chaperones in the cell organelle is mediated by the C‐terminal KDEL (lysine, aspartic acid, glutamic acid and leucine) motif. This motif is recognized by the KDEL receptor, a seven‐transmembrane protein that cycles between the ER and cis‐Golgi to capture missorted KDEL chaperones from post‐ER compartments in a pH‐dependent manner. The KDEL receptor's target chaperones have a substantial role in protein folding and assembly. In this study, the gene expression level of KDEL receptor 1 shows a moderate upregulation during either ER stress or growth of Chinese hamster ovary (CHO) cells in batch culture, while the ER chaperones show higher upregulation. This might indicate the possibility of saturation of the ER retention machinery or at least hindered retention during late stage batch culture in recombinant CHO cells. KDELR1 is overexpressed in a monoclonal antibody‐producing CHO cell line to improve the intracellular chaperone retention rate in the ER. An increase in the specific productivity of IgG1 by 13.2% during the exponential phase, and 23.8% in the deceleration phase of batch culture is observed. This is the first study to focus on the ER retention system as a cell engineering target for enhancing recombinant protein production.     

呼吸道传染病治疗中抗体药物的研发进展

呼吸系统疾病影响着全世界数百万人,主要病变发生在气管、支气管、肺部及胸腔,病变轻者多咳嗽、胸痛,重者呼吸困难、缺氧甚至呼吸衰竭,可造成多种并发症,导致患者严重残疾甚至死亡。治疗性抗体的临床使用为肺癌、哮喘以及各类呼吸道传染病等的治疗开辟了新途径。目前已有数十种抗体（antibodies,Abs）获得市场批准,而且还有更多的抗体药物正在临床开发中。这些Abs中的大多数是针对哮喘、肺癌、慢性阻塞性肺病、特发性肺纤维化以及呼吸道传染病等疾病。其中,呼吸道传染病的爆发具有传播迅猛、传染性强的特点,常引发全球关注,如当下肆虐全球的新型冠状病毒肺炎。针对呼吸道传染病的多种Abs为其临床治疗提供了新策略。基于此,综述了已获准和正在临床开发的适用于治疗呼吸道传染病的Abs,通过综述抗体治疗的分子机制、优势和发展趋势,以期为呼吸道传染病治疗中抗体药物的研发提供参考。     

Effectiveness of host cell protein removal using depth filtration with a filter containing diatomaceous earth

The increased cell density and product titer in biomanufacturing have led to greater use of depth filtration as part of the initial clarification of cell culture fluid, either as a stand-alone unit operation or after centrifugation. Several recent studies have shown that depth filters can also reduce the concentration of smaller impurities like host cell proteins (HCP) and DNA, decreasing the burden on subsequent chromatographic operations. The objective of this study was to evaluate the HCP removal properties of the Pall PDH4 depth filter media, a model depth filter containing diatomaceous earth, cellulose fibers, and a binder. Experiments were performed with both cell culture fluid (CCF) and a series of model proteins with defined pI, molecular weight, and hydrophobicity chosen to match the range of typical HCP. The location of adsorbed (fluorescently labeled) proteins within the depth filters was determined using confocal scanning laser microscopy. Protein binding was greater for proteins that were positively charged and more hydrophobic, consistent with adsorption to the negatively charged diatomaceous earth. The lowest degree of binding was seen with proteins near their pI, which were poorly removed by this filter. These results provide new mechanistic insights into the factors governing the filter capacity and performance characteristics of depth filters containing diatomaceous earth that are widely used in the clarification of CCF.     

Modelling the effect of birth and feeding modes on the development of human gut microbiota

The human gut microbiota is transmitted from mother to infant through vaginal birth and breastfeeding. Bifidobacterium, a genus that dominates the infants’ gut, is adapted to breast milk in its ability to metabolize human milk oligosaccharides; it is regarded as a mutualist owing to its involvement in the development of the immune system. The composition of microbiota, including the abundance of Bifidobacteria, is highly variable between individuals and some microbial profiles are associated with diseases. However, whether and how birth and feeding practices contribute to such variation remains unclear. To understand how early events affect the establishment of microbiota, we develop a mathematical model of two types of Bifidobacteria and a generic compartment of commensal competitors. We show how early events affect competition between mutualists and commensals and microbe-host-immune interactions to cause long-term alterations in gut microbial profiles. Bifidobacteria associated with breast milk can trigger immune responses with lasting effects on the microbial community structure. Our model shows that, in response to a change in birth environment, competition alone can produce two distinct microbial profiles post-weaning. Adding immune regulation to our competition model allows for variations in microbial profiles in response to different feeding practices. This analysis highlights the importance of microbe–microbe and microbe–host interactions in shaping the gut populations following different birth and feeding modes.     

Structure-based Design of a Specific,Homogeneous Luminescence Enzyme Reporter Assay for SARS-CoV-2

Recombinant antibodies (Abs) against the SARS-CoV-2 virus hold promise for treatment of COVID-19 and high sensitivity and specific diagnostic assays. Here, we report engineering principles and realization of a Protein-fragment Complementation Assay (PCA) detector of SARS-CoV-2 antigen by coupling two Abs to complementary N- and C-terminal fragments of the reporter enzyme Gaussia luciferase (Gluc). Both Abs display comparably high affinities for distinct epitopes of viral Spike (S)-protein trimers. Gluc activity is reconstituted when the Abs are simultaneously bound to S-protein bringing the Ab-fused N- and C-terminal fragments close enough together (8 nm) to fold. We thus achieve high specificity both by requirement of simultaneous binding of the two Abs to the S-protein and also, in a steric configuration in which the two Gluc complementary fragments can fold and thus reconstitute catalytic activity. Gluc activity can also be reconstituted with virus-like particles that express surface S-protein with detectable signal over background within 5 min of incubation. Design principles presented here can be readily applied to develop reporters to virtually any protein with sufficient available structural details. Thus, our results present a general framework to develop reporter assays for COVID-19, and the strategy can be readily deployed in response to existing and future pathogenic threats and other diseases.     

Serum levels of anti-heat shock protein 27 antibodies in patients with chronic liver disease

Heat shock protein 27 (HSP27), an intracellular molecular chaperone, is involved in the pathogenesis of cancer by promoting both tumor cell proliferation and resistance to therapy. HSP27 is also present in the circulation and circulating HSP27 (sHSP27) can elicit an autoimmune response with production of antibodies. Levels of sHSP27 are enhanced in patients with hepatocellular carcinoma (HCC); it is, however, unknown whether changes in HSP27 antibody levels occur in patients with HCC and can be exploited as a circulating biomarker of HCC. Our aim was to assess the potential association between newly diagnosed HCC and serum anti-HSP27 antibody levels. In this cross-sectional study, anti-HSP27 antibody levels were measured in serum samples from 71 HCC patients, 80 subjects with chronic liver disease, and 38 control subjects by immunoenzymatic assay. Anti-HSP27 antibody levels did not differ significantly among groups. However, in patients with chronic active hepatitis/cirrhosis, anti-HSP27 levels were significantly higher in subjects with a positive history of alcoholism (p = 0.03). Our data do not support the hypothesis that anti-HSP27 antibody levels may help identify patients with HCC among subjects with chronic liver disease. However, our finding that alcohol-related liver disease is associated with higher anti-HSP27 levels is novel and deserves further investigations.