Ticks and the pathogens they transmit, including bacteria, viruses, protozoa, and helminths, constitute a growing burden for human and animal health worldwide. The ability of some animal species to acquire resistance to blood-feeding by ticks after a single or repeated infestation is known as acquired tick resistance (ATR). This resistance has been associated to tick-specific IgE response, the generation of skin-resident memory CD4+ T cells, basophil recruitment, histamine release, and epidermal hyperplasia. ATR has also been associated with protection to tick-borne tularemia through allergic klendusity, a disease-escaping ability produced by the development of hypersensitivity to an allergen. In addition to pathogen transmission, tick infestation in humans is associated with the α-Gal syndrome (AGS), a type of allergy characterized by an IgE response against the carbohydrate Galα1-3Gal (α-Gal). This glycan is present in tick salivary proteins and on the surface of tick-borne pathogens such as Borrelia burgdorferi and Anaplasma phagocytophilum, the causative agents of Lyme disease and granulocytic anaplasmosis. Most α-Gal-sensitized individuals develop IgE specific against this glycan, but only a small fraction develop the AGS. This review summarizes our current understanding of ATR and its impact on the continuum α-Gal sensitization, allergy, and the AGS. We propose that the α-Gal-specific IgE response in humans is an evolutionary adaptation associated with ATR and allergic klendusity with the trade-off of developing AGS.
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Cover Image
Cover Image
In this issue Samantha and colleagues (pp. 1749–1767) provide insights into the underlying mechanism that governs the recognition of myo-inositol by TNYR SaPLD. The image shows an overlay of the loop conformations of four different structures. The unliganded TNYR structure is coloured magenta, in teal is the structure of the H168A mutant bound to PA, in green is the WT unliganded structure and in grey is the TNYR structure bound to phosphate. Image courtesy of Alice Vrielink.
Tick–human interactions: from allergic klendusity to the α-Gal syndrome
Alejandro Cabezas-Cruz, Adnan Hodžić, Lourdes Mateos-Hernández, Marinela Contreras, José de la Fuente; Tick–human interactions: from allergic klendusity to the α-Gal syndrome. Biochem J 14 May 2021; 478 (9): 1783–1794. doi: https://doi.org/10.1042/BCJ20200915
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