Persistent Infections and Immunity in Ruminants to Arthropod-Borne Bacteria in the Family Anaplasmataceae

Brown, Wendy C.; Barbet, Anthony F.

doi:10.1146/annurev-animal-022513-114206

Cited by 31 publications

(24 citation statements)

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“…A. marginale has developed several mechanisms for evading host adaptive immunity (25). First, A. marginale undergoes extensive antigenic variation in immunodominant MSP2 and MSP3 (26,27).…”

Section: Discussionmentioning

confidence: 99%

Cooperation of PD-1 and LAG-3 Contributes to T-Cell Exhaustion in Anaplasma marginale-Infected Cattle

et al. 2016

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c The CD4؉ T-cell response is central for the control of Anaplasma marginale infection in cattle. However, the infection induces a functional exhaustion of antigen-specific CD4 ؉ T cells in cattle immunized with A. marginale outer membrane proteins or purified outer membranes (OMs), which presumably facilitates the persistence of this rickettsia. In the present study, we hypothesize that T-cell exhaustion following infection is induced by the upregulation of immunoinhibitory receptors on T cells, such as programmed death 1 (PD-1) and lymphocyte activation gene 3 (LAG-3). OM-specific T-cell responses and the kinetics of PD-1-positive (PD-1 ؉ ) LAG-3 ؉ exhausted T cells were monitored in A. marginale-challenged cattle previously immunized with OMs. Consistent with data from previous studies, OM-specific proliferation of peripheral blood mononuclear cells (PBMCs) and interferon gamma (IFN-␥) production were significantly suppressed in challenged animals by 5 weeks postinfection (wpi). In addition, bacteremia and anemia also peaked in these animals at 5 wpi. Flow cytometric analysis revealed that the percentage of PD-1 ؉ LAG-3 ؉ T cells in the CD4 ؉ , CD8 ؉ , and ␥␦ T-cell populations gradually increased and also peaked at 5 wpi. A large increase in the percentage of LAG-3 ؉ ␥␦ T cells was also observed. Importantly, in vitro, the combined blockade of the PD-1 and LAG-3 pathways partially restored OM-specific PBMC proliferation and IFN-␥ production at 5 wpi. Taken together, these results indicate that coexpression of PD-1 and LAG-3 on T cells contributes to the rapid exhaustion of A. marginale-specific T cells following infection and that these immunoinhibitory receptors regulate T-cell responses during bovine anaplasmosis.

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“…A. marginale has developed several mechanisms for evading host adaptive immunity (25). First, A. marginale undergoes extensive antigenic variation in immunodominant MSP2 and MSP3 (26,27).…”

Section: Discussionmentioning

confidence: 99%

Cooperation of PD-1 and LAG-3 Contributes to T-Cell Exhaustion in Anaplasma marginale-Infected Cattle

et al. 2016

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“…Anaplasma phagocytophilum infection was found in 14 of 17 study sites in the present study, implying an extensive geographical distribution of the agent in China. It is well known that A. phagocytophilum could cause a persistent infection in sheep and rodents, which allows them to be reservoirs of infection [25]. The sheep and goats serve as reservoir hosts may facilitate further spread of infection.…”

Section: Discussionmentioning

confidence: 99%

Anaplasma phagocytophilum in sheep and goats in central and southeastern China

et al. 2016

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Background Anaplasma phagocytophilum is wide spread throughout the world and impacts both human and animal health. Several distinct ecological clusters and ecotypes of the agent have been established on the basis of various genetic loci. However, information on the genetic variability of A. phagocytophilum isolates in China represents a gap in knowledge. The objective of this study was to determine the prevalence and genetic characterization of A. phagocytophilum in small ruminants in central and southeastern China.MethodsThe presence of A. phagocytophilum was determined in 421 blood samples collected from small ruminants by PCR. Positive samples were genetically characterized based on 16S rRNA and groEL genes. Statistical analyses were conducted to identify ecotypes of A. phagocytophilum strains, to assess their host range and zoonotic potential.ResultsOut of 421 sampled small ruminants, 106 (25.2%) were positive for A. phagocytophilum. The positive rate was higher in sheep (35.1%, 40/114) than in goats (26.4%, 66/307) (P < 0.05). Sequence analyses revealed that the isolates identified in this study were placed on two separate clades, indicating that two 16S rRNA variants of A. phagocytophilum were circulating in small ruminants in China. However, analysis using obtained groEL sequences in this study formed one cluster, which was separate from other known ecotypes reported in Europe. In addition, a novel Anaplasma sp. was identified and closely related to an isolate previously reported in Hyalomma asiaticum, which clustered independently from all recognized Anaplasma species.ConclusionsA molecular survey of A. phagocytophilum was conducted in sheep and goats from ten provinces in central and southeastern China. Two 16S rRNA variants and a new ecotype of A. phagocytophilum were identified in small ruminants in China. Moreover, a potential novel Anaplasma species was reported in goats. Our findings provide additional information on the complexity of A. phagocytophilum in terms of genetic diversity in China.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-016-1880-z) contains supplementary material, which is available to authorized users.

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“…Beside Babesia, the Anaplasma and Ehrlichia are also important tick-borne pathogens of zoonotic importance (Brown and Barbet 2016). The tick-borne disease caused by Anaplasma phagocytophilum is a serious zoonotic disease which infects humans, cattle, equines and canines.…”

Section: Tick-borne Diseasesmentioning

confidence: 99%

Climatic changes and their role in emergence and re-emergence of diseases

El-Sayed

Kamel

2020

Environ Sci Pollut Res

261

145

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Global warming and the associated climate changes are predictable. They are enhanced by burning of fossil fuels and the emission of huge amounts of CO 2 gas which resulted in greenhouse effect. It is expected that the average global temperature will increase with 2-5°C in the next decades. As a result, the earth will exhibit marked climatic changes characterized by extremer weather events in the coming decades, such as the increase in temperature, rainfall, summertime, droughts, more frequent and stronger tornadoes and hurricanes. Epidemiological disease cycle includes host, pathogen and in certain cases intermediate host/vector. A complex mixture of various environmental conditions (e.g. temperature and humidity) determines the suitable habitat/ecological niche for every vector host. The availability of suitable vectors is a precondition for the emergence of vector-borne pathogens. Climate changes and global warming will have catastrophic effects on human, animal and environmental ecosystems. Pathogens, especially neglected tropical disease agents, are expected to emerge and re-emerge in several countries including Europe and North America. The lives of millions of people especially in developing countries will be at risk in direct and indirect ways. In the present review, the role of climate changes in the spread of infectious agents and their vectors is discussed. Examples of the major emerging viral, bacterial and parasitic diseases are also summarized.

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Persistent Infections and Immunity in Ruminants to Arthropod-Borne Bacteria in the Family Anaplasmataceae

Cited by 31 publications

References 182 publications

Cooperation of PD-1 and LAG-3 Contributes to T-Cell Exhaustion in Anaplasma marginale-Infected Cattle

Cooperation of PD-1 and LAG-3 Contributes to T-Cell Exhaustion in Anaplasma marginale-Infected Cattle

Anaplasma phagocytophilum in sheep and goats in central and southeastern China

Climatic changes and their role in emergence and re-emergence of diseases

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