Eloy JO, Ruiz A, de Lima FT, Petrilli R, Raspantini G, et al.
Colloids and surfaces. B, Biointerfaces •
Prostate cancer is the second cause of cancer death in men worldwide. Docetaxel (DTX), an antimitotic drug, is widely used for the treatment of metastatic prostate cancer patients. Taxotere® is a commercial DTX formulation. It contains a polysorbate 80 surfactant to improve DTX aqueous solubility, which has been associated with hypersensitivity reactions in patients. Liposomes have been used as promising delivery systems for a range of hydrophobic drugs, such as DTX, offering improved drug water solubility and biocompatibility, without compromising its anticancer activity. Herein, DTX-loaded liposomes were developed using the Box-Behnken factorial design. The optimized formulation was nano-sized, homogenous in size (67.47 nm) with high DTX encapsulation efficiency (99.95 %). The encapsulated DTX was in a soluble amorphous state, which was slowly released. Next, to increase the liposomes selectivity to prostate cancer cells, cetuximab, an anti-EGFR monoclonal antibody. was successfully conjugated to the surface of liposomes, without compromising cetuximab protein structure and stability. As expected, our results showed higher cellular uptake and toxicity of immunoliposomes, compared to non-targeted liposomes, in DU145 (EGFR-overxpressing) prostate cancer cells. To the best of our knowledge, this is the first report of engineering EGFR-targeted liposomes to enhance the selectivity of DTX delivery to EGFR-positive prostate cancer cells.
Mateos-Hernández L, Obregón D, Maye J, Borneres J, Versille N, et al.
Vaccines •
The tick microbiota is a highly complex ensemble of interacting microorganisms. Keystone taxa, with a central role in the microbial networks, support the stability and fitness of the microbial communities. The keystoneness of taxa in the tick microbiota can be inferred from microbial co-occurrence networks. Microbes with high centrality indexes are highly connected with other taxa of the microbiota and are expected to provide important resources to the microbial community and/or the tick. We reasoned that disturbance of vector microbiota by removal of ubiquitous and abundant keystone bacteria may disrupt the tick-microbiota homeostasis causing harm to the tick host. These observations and reasoning prompted us to test the hypothesis that antibodies targeting keystone bacteria may harm the ticks during feeding on immunized hosts. To this aim, in silico analyses were conducted to identify keystone bacteria in the microbiota of nymphs. The family Enterobacteriaceae was among the top keystone taxa identified in microbiota. Immunization of α-1,3-galactosyltransferase-deficient-C57BL/6 (α1,3GT KO) mice with a live vaccine containing the Enterobacteriaceae bacterium strain BL21 revealed that the production of anti- and anti-α-Gal IgM and IgG was associated with high mortality of nymphs during feeding. However, this effect was absent in two different strains of wild type mice, BALB/c and C57BL/6. This result concurred with a wide distribution of α-1,3-galactosyltransferase genes, and possibly α-Gal, in Enterobacteriaceae and other bacteria of tick microbiota. Interestingly, the weight of nymphs that fed on -immunized C57BL/6 was significantly higher than the weight of ticks that fed on C57BL/6 immunized with a mock vaccine. Our results suggest that anti-tick microbiota vaccines are a promising tool for the experimental manipulation of vector microbiota, and potentially the control of ticks and tick-borne pathogens.
Human cell lines can produce recombinant proteins much more similar to their natural counterpart, compared to other mammalian cell lines, reducing potential immunogenic reactions. Recombinant proteins produced in nonhuman cells can have in its structure glycan epitopes, such as Galα1,3-Gal (alpha-Gal) and N-glycolylneuraminic acid (Neu5Gc) residues, that are antigenic to humans and can potentially affect the efficacy of the recombinant product. Therefore, the production of recombinant factor VIII (rFVIII) in human cell lines is a new approach to avoid nonhuman glycosylation. Here, we describe a protocol to produce rFVIII in the human cell line SK-HEP, using a lentiviral vector to produce high quantities of the recombinant protein.
The journal of allergy and clinical immunology. In practice •
Hypersensitivity reactions (HSRs) to monoclonal antibodies (mAbs) are increasingly frequent as this class of therapeutic agents is rapidly expanding. Immediate and nonimmediate HSRs have been reported with mAbs. Immediate HSRs can be explained by 3 main mechanisms: cytokine release syndrome, IgE-mediated, and IgG-mediated reactions. Importantly, IgE-mediated reactions can occur on first exposure due to preformed specific IgEs, as shown for cetuximab. Almost all patients with an immediate HSR can be safely re-exposed either through desensitization or challenge depending on the severity and mechanism of the initial reaction. An algorithm detailing the general approach to these HSRs and the preferred method of re-exposure is presented in this review. Also, the mAbs that are most frequently implicated in HSRs are discussed individually.
Trypomastigote forms of Trypanosoma cruzi, the causative agent of Chagas Disease, shed extracellular vesicles (EVs) enriched with glycoproteins of the gp85/trans-sialidase (TS) superfamily and other α-galactosyl (α-Gal)-containing glycoconjugates, such as mucins. Here, purified vesicles from T. cruzi strains (Y, Colombiana, CL-14 and YuYu) were quantified according to size, intensity and concentration. Qualitative analysis revealed differences in their protein and α-galactosyl contents. Later, those polymorphisms were evaluated in the modulation of immune responses (innate and in the chronic phase) in C57BL/6 mice. EVs isolated from YuYu and CL-14 strains induced in macrophages higher levels of proinflammatory cytokines (TNF-α and IL-6) and nitric oxide via TLR2. In general, no differences were observed in MAPKs activation (p38, JNK and ERK 1/2) after EVs stimulation. In splenic cells derived from chronically infected mice, a different modulation pattern was observed, where Colombiana (followed by Y strain) EVs were more proinflammatory. This modulation was independent of the T. cruzi strain used in the mice infection. To test the functional importance of this modulation, the expression of intracellular cytokines after in vitro exposure was evaluated using EVs from YuYu and Colombiana strains. Both EVs induced cytokine production with the appearance of IL-10 in the chronically infected mice. A high frequency of IL-10 in CD4+ and CD8+ T lymphocytes was observed. A mixed profile of cytokine induction was observed in B cells with the production of TNF-α and IL-10. Finally, dendritic cells produced TNF-α after stimulation with EVs. Polymorphisms in the vesicles surface may be determinant in the immunopathologic events not only in the early steps of infection but also in the chronic phase.
The journal of allergy and clinical immunology. In practice •
Biological agents are used in the treatment of neoplastic, autoimmune, and inflammatory diseases and their clinical applications are becoming broader. Following their increased utilization, hypersensitivity reactions linked to these drugs have become more frequent, sometimes preventing the use of first-line therapies. The clinical presentation of hypersensitivity reactions to biological agents ranges from mild cutaneous manifestations to life-threatening reactions. In this scenario, rapid desensitization is a groundbreaking procedure that enables selected patients to receive the full treatment dose in a safe way, in spite of their immediate hypersensitivity reaction to the drug, and protects them against anaphylaxis. The aim of this review is to update and discuss some of the main biological agents used in clinical practice (rituximab, trastuzumab, cetuximab, ofatumumab, tocilizumab, brentuximab, omalizumab, and tumor necrosis factor alpha inhibitor agents) and their associated hypersensitivity reactions, including clinical presentations, diagnosis, and treatment in the acute setting. In addition, novel management options with rapid desensitization are presented.
Yokoyama-Yasunaka JK, Piazza RM, Umezawa ES, Stolf AM
Journal of clinical laboratory analysis •
Here, we show that antigal antibodies from Chagas' disease patients react with noninfected host cells previously treated with antigens secreted by the trypomastigote forms of Trypanosoma cruzi. With the exception of human and Old World monkey cells, which are GAL-negative, cells of all mammals express the GAL epitope (Gal alpha (1-3)Gal beta (1-4)GlcNAc-R) on their surface. Thus only the former ones develop antigal antibodies. Antigal antibodies increase during infection with T. cruzi, which expresses GAL epitopes on the surface of the infective forms. Here, we show that incubation of noninfected, GAL-negative cells with antigens shed by T. cruzi renders these cells reactive to antigal antibodies purified from chagasic sera. Neither chagasic sera depleted of antigal antibodies nor antigal antibodies purified from normal sera display reactivity with treated cells. Cell reactivity of chagasic antigal was abolished in the presence of melibiose (Gal alpha (1-6)Glc) or gal-gal (methyl 3-O-alpha-D-galactopyranosyl alpha-D-galactopyranoside). Since shedding of T. cruzi antigens can occur in vivo, these antigens may induce reactivity of chagasic antigal with noninfected human cells. The reactivity of noninfected, GAL-negative cells observed only with chagasic antigal antibodies can amplify the range of reactivity of these antibodies and consequently adds to their importance in the pathogenesis of human Chagas' disease.
Couto AS, Gonçalves MF, Colli W, de Lederkremer RM
Molecular and biochemical parasitology •
The structure of the N-linked oligosaccharide of the 85-kDa surface glycoprotein (Tc-85) from the infective trypomastigote form of Trypanosoma cruzi was investigated. Tc-85 metabolically labeled with [14C]glucose was purified by affinity chromatography on wheat germ agglutinin-Sepharose. Binding to the lectin was lost on treatment of Tc-85 with neuraminidase. The N-linked asialo-oligosaccharide was released by endo-beta-N-acetylglucosaminidase F digestion of asialo-Tc-85 and was further analyzed using specific exoglycosidases. [14C]fucose was detected after alpha-L-fucosidase treatment or mild acid hydrolysis. The afucosyl oligosaccharide was 3H-labeled by the galactose oxidase-NaB3H4 method. [3H]Galactose was released by alpha-galactosidase, and only then was beta-galactosidase effective in removing another galactose. The gal(alpha 1-3)gal unit was demonstrated by periodate oxidation studies on the [3H]galactose-labeled asialo-glycoprotein. The presence of gal(alpha 1-3)gal in Tc-85 could be related to the recent finding of elevated antibody levels against this epitope in patients with Chagas' disease.
