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Histoplasmosis
Published in Rebecca A. Cox, Immunology of the Fungal Diseases, 2020
Animal serum incorporated into culture media inhibits the growth of many species of fungi.43 Such growth suppression is caused most often by serum transferrin which binds iron and makes it unavailable for utilization by microorganisms.42,43 Addition of iron to serum-containing media reverses the fungistatic activity of those media.43 Iron is essential for a number of metabolic processes in microbial cells and H. capsulatum acquires it by means of the hydroxamic type siderophore.41,44,45 The transferrin in serum or the conalbumin in egg white can bind enough iron to inhibit the growth of H. capsulatum in media containing those substances.46–48 The percent saturation of transferrin in the serum of normal subjects or of patients with histoplasmosis is in a range which inhibits the growth of H. capsulatum in vitro.48 Saturation of the transferrin in serum specimens allows the fungus to grow unimpeded.48 These observations indicate that plasma transferrin may be important in restricting the extracellular replication of H. capsulatum.
Food allergens
Published in Richard F. Lockey, Dennis K. Ledford, Allergens and Allergen Immunotherapy, 2020
Several studies have identified the major chicken egg allergens [27,28]. Ovomucoid (Gal d 1), a glycoprotein with a molecular weight of 28 kDa and an acidic isoelectric point, is the major egg allergen. In a study of 18 children with egg allergy, ovomucoid was a more potent allergen than purified ovalbumin as determined by skin prick and in vitro specific IgE tests [29]. While previous studies indicated that ovalbumin was the major egg allergen, this work demonstrated ovomucoid contamination of the ovalbumin accounted for the discrepancy. Ovalbumin (Gal d 2) is a monomeric phosphoglycoprotein with a molecular weight of 43–45 kDa and an acidic isoelectric point. Purified ovalbumin has three primary variants, A1, A2, and A3. It is difficult to determine the exact role of Gal d 2 because of ovomucoid contamination of ovalbumin [29]. Ovotransferrin (Gal d 3), or conalbumin, has a molecular weight of 78 kDa, an acidic isoelectric point, and antimicrobial activity and iron-binding properties. Lysozyme (Gal d 4) is a lower molecular weight allergen (14.3 kDa) that in some studies appears to be a major allergen but in other studies is a minor allergen. Other minor allergens in eggs include serum albumin (Gal d 5), YGP42 (Gal d 6), myosin light chain 1f (Gal d 7), α-parvalbumin (Gal d 8), β-enolase (Gal d 9), and aldolase (Gal d 10). The carbohydrate portion of the glycoproteins in eggs, particularly in ovomucoid, does not play a primary role in specific IgE binding.
Immunohistochem1Cal Studies with Antibodies to the Chicken Oviduct Progesterone Receptor
Published in Louis P. Pertschuk, Sin Hang Lee, Localization of Putative Steroid Receptors, 2019
Jean-Marie Gase, Etienne-Emile Baulieu
In our laboratory, several forms and components of the progesterone receptor (PR) of the chick oviduct2-5 have been purified and antibodies have been obtained.5-8 The chick oviduct system is suitable for detailed studies of steroid hormone action, since hormonal responses are relatively well characterized biochemically and cytologically. Egg white proteins, like ovalbumin, conalbumin, etc. that are synthetized under hormone action, are available in pure forms. The progesterone receptor itself is abundant after estrogen priming9,10 and the molecular biology of the system is under constant investigation.
Food allergy severity predictions based on cellular in vitro tests
Published in Expert Review of Molecular Diagnostics, 2020
Betul Buyuktiryaki, Alexandra F. Santos
The main allergens of egg are ovomucoid (Gal d 1), ovalbumin (Gal d 2), ovotransferrin/conalbumin (Gal d 3), and lysozyme (Gal d 4). Ovomucoid is an immunodominant allergen owing to its stable structure to heat and proteolysis [63] and has been shown to predict clinic reactivity to baked eggThe major allergens of. However, neither ovomucoid nor the other egg allergen components were effective in predicting the severity of reactions to egg [79]. In Japan, 156 children aged 0–6 years from 11 centers underwent OFC to boiled egg, and, based on the outcome, probability curves depicted ovomucoid sIgE in relation to the severity of reactions [80]. The curve of predicted probabilities showed that the ovomucoid sIgE of 22.4 kU/L had a 95% probability for predicting any symptoms, and 3.8 kU/L had a 5% probability for predicting reactions greater than grade 3. The authors suggested 5% probability curve for severe reactions might help clinicians to make decisions about indications and protocol of OFC.
The role of trogocytosis in immune surveillance of Hodgkin lymphoma
Published in OncoImmunology, 2020
Trogocytosis is a fast intercellular transfer of membrane fragments along with the proteins inserted into or associated with them, which can happen within minutes. Although intercellular transfer of membranes had been observed earlier in prokaryotes, the term trogocytosis was only applied to describe these transfers in mammalian cells in 2002.20 The proteins in the small membrane fragments pinched off from the donor cell are either displayed on the acceptor cell surface or are internalized.9,10 Therefore, trogocytosis helps explaining why certain cell type-specific proteins are present on other cells that do not express them.21 For example, myelin basic protein-specific T cells, after being activated by allogenic antigen presenting cells (APCs), can present myelin basic protein and conalbumin antigens to other T cells in a second co-culture, indicating the transfer of membrane patches containing specific and irrelevant peptide-MHC class II (pMHCII) from the APC to the T cells.22 Although the transfer of proteins is not specific, trogocytosis is mediated and facilitated by specific ligand-receptor interactions. The anti-MHC antibody (OX6) could block the transfer of pMHCII in aforementioned allogenic reactions.22 Therefore, trogocytosis mediated by specific antigen-TCR interactions can aid in the discovery of novel epitopes for clinically employed TCR.23