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Infection and Inflammation
Published in Michael Ljungberg, Handbook of Nuclear Medicine and Molecular Imaging for Physicists, 2022
Erik H. J. G. Aarntzen, Andor W. J. M. Glaudemans
In particular, macrophages release soluble factors, for example, prostaglandins, leukotrienes, and platelet-activation factor, or chemokines, which facilitate the recruitment of other immune cells [5–7]. For example, tumour-necrosis factor α (TNFα) is an activator of endothelial cells; interleukin-8 (CXCL8) is involved in the recruitment of neutrophils to the site of infection, and interleukin-1β (IL-1β) and interleukin-6 (IL-6) induce systemic acute-phase responses in the liver. Antibody-antigen complexes and surface molecules on pathogens can induce the activation of other, non-eukaryotic, components of the immune system; the complement system, and platelets [8, 9]. The complement system consists of plasma proteins that react to mark pathogens for phagocytosis, a process called opsonization, and help exaggerate immune response.
Biologic Drug Substance and Drug Product Manufacture
Published in Anthony J. Hickey, Sandro R.P. da Rocha, Pharmaceutical Inhalation Aerosol Technology, 2019
Ajit S. Narang, Mary E. Krause, Shelly Pizarro, Joon Chong Yee
In the body, an antibody is a protein produced by β-lymphocytes in response to substances recognized as foreign (“antigens”). Antibodies recognize and bind to antigens, resulting in their inactivation or opsonization (binding of antibody to the membrane surface of invading pathogen, thus marking it for phagocytosis) or complement-mediated destruction. Antibodies are also known as immunoglobulins (abbreviated Ig) since they are immune-response proteins that are globular proteins (compact with higher orders of structure and hydrophilic surface making them soluble; as opposed to fibrous proteins, which have predominantly secondary structure and are insoluble). Of the five major types of antibodies (Table 8.1), immunoglobulin G (IgG) is preferred for therapeutic applications due to its wide distribution and function.
Nanomaterials for the Delivery of Therapeutic Nucleic Acids
Published in Klaus D. Sattler, st Century Nanoscience – A Handbook, 2020
Michael Riley, Wilfred Vermerris
Opsonization is the process by which a foreign molecule or antigen is coated with serum proteins, to make them more susceptible to recognition by immune cells, specifically macrophages that can take up these tagged molecules via phagocytosis. The best known opsonins are antibodies and complement proteins. These two groups of proteins are responsible for neutralizing toxins, pathogens, and other foreign particles and then facilitate macrophage phagocytosis (Gordon 2016). Other nonspecific proteins such as collectins, ficolins, and serum albumin proteins can also function in an opsonization-like manner. Consequently, nonviral vectors have to avoid these different classes of proteins to avoid being destroyed or removed before they reach their target site. Research has shown that hydrophobic particles tend to have a higher degree of opsonization and subsequent inactivation and removal compared to hydrophilic particles (Carrstensen, Müller, and Müller 1992). Grafting the shielding groups onto the NP is an effective way to minimize opsonization, and is most commonly accomplished with polyethylene glycol (PEG) and related compounds (Peracchia et al. 1999). Once the NPs have been shielded, they have a better chance at avoiding the RES. This system is part of the immune system and is comprised of monocytes and macrophages in the liver and spleen that take up particles tagged by opsonin proteins. It is important to realize that opsonin proteins facilitate the uptake by macrophages, but that the macrophages and the RES itself can still remove and clear NPs even when they are not modified with opsonin proteins. Hence, in addition to shielding the NPs, decreasing their size can help prevent clearance by the RES (Gaur et al. 2000).
Novel spray-dried PHA microparticles for antitumor drug release
Published in Drying Technology, 2018
Anna Shershneva, Anastasiya Murueva, Elena Nikolaeva, Ekaterina Shishatskaya, Tatiana Volova
It is reported that the addition of surfactants to polymers like polyhydroxybutyrate affects physicochemical properties of the particles.[41] Studies also highlight the role of surfactants in increasing the elasticity, reducing the degree of crystallinity of P3HB, facilitates the penetration of water into the polymer matrix.[42] PEG is the most commonly used non-ionic surfactant, which is said to be a hydrophilic non-toxic segment in combination with hydrophobic biodegradable aliphatic polyethers.[43,44] PEG escapes the initial defense process from the immune system due to its biocompatible properties, which result in higher circulation period in the blood stream by creating a spatial barrier that prevents the opsonization process.[45]
Targeted delivery and anticancer effects of Chrysin-loaded chitosan-folic acid coated solid lipid nanoparticles in pancreatic malignant cells
Published in Journal of Biomaterials Science, Polymer Edition, 2023
Amin Farhadi, Masoud Homayouni Tabrizi, Soroush Sadeghi, Danial Vala, Tina Khosravi
For all the benefits of SLNs, their use is limited by their inability to control drug release under systemic conditions [14]. On the other hand, the hydrophobic nature and the existence of a negative surface charge of these NPs make it possible to identify and easily remove them by the immune system, and this cause’s rapid clearance of nanocarriers (NCs) under the effect of opsonization [15]. The existence of such limitations highlights the need to modify the surface of NPs in order to optimize the formulation and increase the effectiveness of the treatment. In this regard, Hanafy et al. demonstrated the improved anticancer impact of curcumin by crosslinking it to carboxy methyl cellulose and increasing its membrane permeability [16].
Focal therapy for localized cancer: a patent review
Published in Expert Review of Medical Devices, 2021
Jette Bloemberg, Luigi Van Riel, Dimitra Dodou, Paul Breedveld
With regard to the treatment means, most patents describe an instrument using energy. The low preference in using matter to treat cancer might be explained by the long-term toxicity concerns of remaining matter, especially non-biodegradable matter [218,219]. Energy does not possess this risk of long-term toxicity, as the energy is removed from the body together with the removal of the energy source. Another barrier of matter is the body’s labeling of foreign particles by opsonization to stimulate the removal of those foreign particles [218]. In opsonization, the foreign particles are covered with nonspecific proteins to make them more visible to phagocytic cells, so phagocytosis can occur [218,220].