Project description:Alpha-gal syndrome (AGS) is a delayed allergic response to red meat caused by the production of alpha-gal-specific IgE following certain tick bites. We designed this study to characterize the underlying immune response to tick bites associated with AGS. Our results suggest that Amblyomma americanum bites direct mouse immunity toward Th2 following the initial burst of proinflammatory response and facilitate host sensitization to the α-gal antigen.
Project description:Transcriptional profiling of lymph nodes of three cattle breeds (Bonsmara, Brahman, Holstein-Friesian) in response to the cattle tick (Rhipicephalus microplus) larvae and adult infestation. Emphasis is placed on firstly, comparing transcriptional responses within a cattle breed, before and after infestation, and secondly, comparing differentially expressed genes common between the breeds.
Project description:Understanding the molecular basis of how the tick adapts to feed on different animal hosts is central to understanding tick and tick-borne disease (TBD) epidemiology. Tick adaptation to feed on vertebrate hosts is regulated by tick secretion of multiple tick saliva proteins (TSPs) and other molecules that regulate tick feeding. This study was initiated to determine if ticks such as Ixodes scapularis and Amblyomma americanum that are adapted to feed on multiple hosts utilized the same sets of proteins to accomplish feeding on all hosts. Our data suggest that ticks of the same species differentially express proteins when feeding on diffent hosts. SDS-PAGE and silver staining analysis revealed unique protein eletrophoretic profile in saliva of Ixodes scapularis and Amblyomma americanum that were stimulated to start feeding on different hosts: rabbits, humans, and dogs. LC-MS/MS sequencing and pairwise analysis of proteins in saliva of I. scapularis and A. americanum ticks that were non-stimulated and those that were stimulated to feed on rabbits, dogs, or humans identified TSPs that were unique to each treatment and those that were common. Overal, we identified a total of 276 and 340 non-redundant I. scapularis and A. americanum TSPs, which we have classified into 28 functional classes that include secreted conserved proteins (unknown functions), proteinase inhibitors, lipocalins, extracellular matrix/cell adhesion, heme/iron metabolism, signal transduction and immunity-related proteins being the most predominant in saliva of unfed ticks. With exception of Rhipicephalus microplus, anti-tick vaccine research relies on feeding lab animals. Data here suggest that lab animal data could result in prioritizing irrelevant targets as some tick genes are unique to ticks fed on lab animals. This study provides the platform that could be utilized to identify relevant target anti-tick vaccine antigens, and will facilitate early stage tick feeding research.
Project description:Tick infestations by Rhipicephalus microplus, the cattle tick, cause enormous losses to health and animal production. Ticks induce immune response in their hosts; therefore their immunobiological control is feasible. The available anti-tick vaccines display variable efficacy and short-lived, encouraging the search for new protective antigens. The identification of important genes in tick parasitism may indicate protective antigens useful to compose an anti-tick vaccine. We have developed and tested so far four recombinant salivary antigens as a multicomponent anti-tick vaccine in tick-susceptible bovines (Holstein breed). The challenge with R. microplus larvae displayed that tick infestation in vaccinated bovines was significantly reduced. In order to elucidate the molecular mechanisms trigged after immunisation and during infestation, RNA-seq data of peripheral blood from vaccinated and control animals were obtained in different periods of the immunisation trial. A total of 24 mRNA-seq Illumina libraries (single-end, 100 bp) were analysed to identify differential gene expression according to the experimental condition.
Project description:Background Human monocytotropic ehrlichiosis is an emerging life-threatening zoonosis caused by obligately intracellular bacterium, Ehrlichia chaffeensis. E. chaffeensis is transmitted by the lone star tick, Amblyomma americanum, and replicates in mononuclear phagocytes in mammalian hosts. Differences in the E. chaffeensis transcriptome in mammalian and arthropod hosts are unknown. Thus, we determined host-specific E. chaffeensis gene expression in human monocyte (THP-1) and in Amblyomma and Ixodes tick cell lines (AAE2 and ISE6) using a whole genome microarray. Methodology/Principal Findings The majority (~80%) of E. chaffeensis genes were expressed during infection in human and tick cells. There were few differences observed in E. chaffeensis gene expression between the vector Amblyomma and non-vector Ixodes tick cells, but extensive host-specific and differential gene expression profiles were detected between human and tick cells, including higher transcriptional activity in tick cells and identification of gene subsets that were differentially expressed in the two hosts. Differentially and host-specifically expressed ehrlichial genes encoded major immunoreactive tandem repeat proteins (TRP), the outer membrane protein (OMP-1) family, and hypothetical proteins that were 30–80 amino acids in length. Consistent with previous observations, high expression of p28 and OMP-1B genes was detected in human and tick cells, respectively. Notably, E. chaffeensis genes encoding TRP32 and TRP47 were highly upregulated in the human monocytes and expressed as proteins; however, although TRP transcripts were expressed in tick cells, the proteins were not detected in whole cell lysates demonstrating that TRP expression was post transcriptionally regulated. Conclusions/Significance Ehrlichia gene expression is highly active in tick cells, and differential gene expression among a wide variety of host-pathogen associated genes occurs. Furthermore, we demonstrate that genes associated with host-pathogen interactions are differentially expressed and regulated by post transcriptional mechanisms.