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Immune‐mediated hypersensitivity reactions to ticks and other arthropods are well documented. Hypersensitivity to ixodid (hard bodied) ticks is especially important because they transmit infection to humans throughout the world and are responsible for most vector‐borne diseases in the United States. The causative pathogens of these diseases are transmitted in tick saliva that is secreted into the host while taking a blood meal. Tick salivary proteins inhibit blood coagulation, block the local itch response and impair host anti‐tick immune responses, which allows completion of the blood meal. Anti‐tick host immune responses are heightened upon repeated tick exposure and have the potential to abrogate tick salivary protein function, interfere with the blood meal and prevent pathogen transmission. Although there have been relatively few tick bite hypersensitivity studies in humans compared with those in domestic animals and laboratory animal models, areas of human investigation have included local hypersensitivity reactions at the site of tick attachment and generalized hypersensitivity reactions. Progress in the development of anti‐tick vaccines for humans has been slow due to the complexities of such vaccines but has recently accelerated. This approach holds great promise for future prevention of tick‐borne diseases. [ABSTRACT FROM AUTHOR]

Evidence is emerging that some proteins secreted by gall-forming parasites of plants act as effectors responsible for systemic changes in the host plant, such as galling and nutrient tissue formation. A large number of secreted salivary gland proteins ( SSGPs) that are the putative effectors responsible for the physiological changes elicited in susceptible seedling wheat by Hessian fly, Mayetiola destructor ( Say), larvae have been documented. However, how the genes encoding these candidate effectors might respond under field conditions is unknown. The goal of this study was to use microarray analysis to investigate variation in SSGP transcript abundance amongst field collections from different geographical regions (southeastern USA, central USA, and the Middle East). Results revealed significant variation in SSGP transcript abundance amongst the field collections studied. The field collections separated into three distinct groups that corresponded to the wheat classes grown in the different geographical regions as well as to recently described Hessian fly populations. These data support previous reports correlating Hessian fly population structure with micropopulation differences owing to agro-ecosystem parameters such as cultivation of regionally adapted wheat varieties, deployment of resistance genes and variation in climatic conditions. [ABSTRACT FROM AUTHOR]

Dermacentor andersoni , known as the Rocky Mountain wood tick, is found in the western United States and transmits pathogens that cause diseases of veterinary and public health importance including Rocky Mountain spotted fever, tularemia, Colorado tick fever and bovine anaplasmosis. Tick saliva is known to modulate both innate and acquired immune responses, enabling ticks to feed for several days without detection. During feeding ticks subvert host defences such as hemostasis and inflammation, which would otherwise result in coagulation, wound repair and rejection of the tick. Molecular characterization of the proteins and pharmacological molecules secreted in tick saliva offers an opportunity to develop tick vaccines as an alternative to the use of acaricides, as well as new anti-inflammatory drugs. We performed proteomics informed by transcriptomics to identify D. andersoni saliva proteins that are secreted during feeding. The transcript data generated a database of 21,797 consensus sequences, which we used to identify 677 proteins secreted in the saliva of D. andersoni ticks fed for 2 and 5 days, following proteomic investigations of whole saliva using mass spectrometry. Salivary gland transcript levels of unfed ticks were compared with 2 and 5 day fed ticks to identify genes upregulated early during tick feeding. We cross-referenced the proteomic data with the transcriptomic data to identify 157 proteins of interest for immunomodulation and blood feeding. Proteins of unknown function as well as known immunomodulators were identified. [ABSTRACT FROM AUTHOR]

Lygus hesperus Knight (Hemiptera: Miridae) causes economic damage to a wide range of crops in the western United States. While stylet-probing, L. hesperus discharge saliva consisting of lytic enzymes that facilitate extraoral digestion of host tissues. L. hesperus saliva primarily consists of polygalacturonases, α-amylases, and proteases, but salivary constituents other than these enzymes have not been documented. Improved knowledge of L. hesperus salivary proteins could lead to a better understanding of Lygus-- host interactions, and aid in the development of crops that are resistant or tolerant to injury caused by Lygus spp. The objective of our study was to use mass spectrometry to identify salivary proteins of L. hesperus adults. Multiple polygalacturonases and proteases were identified from diet that was stylet-probed and fed upon by L. hesperus. Laccase, alkyl hydroperoxide reductase-like protein, glucose dehydrogenase, and xanthine dehydrogenase were identified in stylet-probed diets by using mass spectrometry, and laccase activity was confirmed using a colorimetric assay. This is the first study to identify laccase, glucose dehydrogenase, and xanthine dehydrogenase from L. hesperus saliva; we propose these enzymes target plant-defense compounds. Nearly 100 proteins from the bacterial plant pathogen, Pantoea ananatis and nine proteins from Serratia spp. were identified in stylet-probed diets. These results suggest L. hesperus may vector these plant pathogens. Our study adds to the list of documented L. hesperus salivary proteins, and provides information that will be useful for the further study of L. hesperus saliva and Lygus-microbe interactions. [ABSTRACT FROM AUTHOR]

Background. Ixodes ticks are the main vectors for Borrelia burgdorferi sensu lato. In the United States, B. burgdorferi is the sole causative agent of Lyme borreliosis and is transmitted by Ixodes scapularis. In Europe, 3 Borrelia species-B. burgdorferi, B. garinii, and B. afzelii-are prevalent, which are transmitted by Ixodes ricinus. The I. scapularis salivary protein Salp15 has been shown to bind to B. burgdorferi outer surface protein (Osp) C, protecting the spirochete from antibody-mediated killing. Methods and results. We recently identified a Salp15 homologue in I. ricinus, Salp15 Iric-1. Here, we have demonstrated, by solid-phase overlays, enzyme-linked immunosorbent assay, and surface plasmon resonance, that Salp15 Iric-1 binds to B. burgdorferi OspC. Importantly, this binding protected the spirochete from antibodymediated killing in vitro and in vivo; immune mice rechallenged with B. burgdorferi preincubated with Salp15 Iric-1 displayed significantly higher Borrelia numbers and more severe carditis, compared with control mice. Furthermore, Salp15 Iric-1 was capable of binding to OspC from B. garinii and B. afzelii, but these Borrelia species were not protected from antibody-mediated killing. Conclusions. Salp15 Iric-1 interacts with all European Borrelia species but differentially protects B. burgdorferi from antibody-mediated killing, putatively giving this Borrelia species a survival advantage in nature. [ABSTRACT FROM AUTHOR]

In the U.S.A., Borrelia burgdorferi, the causative agent of Lyme borreliosis, is transmitted to humans by the ticks Ixodes scapularis and I. pacificus. Tick modulation of host immunity is an important factor in tick transmission of such pathogens. The proliferative responses of lymphocytes from BALB/c and C3H/HeN mice exposed to the salivary-gland soluble proteins (SGSP) of I. scapularis, I. pacificus or Dermacentor andersoni were therefore compared in vitro. This produced the present report, the first to describe the effects of I. pacificus SGSP on the proliferative responses of a host's lymphocytes in vitro. The effects of four concentrations of SGSP from each tick species were evaluated with unstimulated, and concanavalin-A-stimulated lymphocytes of each mouse strain. The responses of lymphocytes from both mouse strains were significantly effected when exposed to SGSP derived from each tick species. Responses of the unstimulated lymphocytes to SGSP indicated that the proteins from I. pacificus suppressed in-vitro lymphocyte proliferation to a greater degree than those from the other species investigated. For the concanavalin-A stimulated cells, however, suppression of the proliferative responses was greatest for cells exposed to I. scapularis SGSP. [ABSTRACT FROM AUTHOR]

The article discusses research being done on human saliva. In a research project called salivary proteomics cataloging, scientists from the U.S. Agricultural Research Service, the University of Rochester and Scripps Research Institute are cataloging the thousands of proteins, lipids, sugars and other molecules found in human saliva. The project is a result of the growing interest in using salivary proteins in diagnosing diseases or detecting illegal-drug use.