Immune defenses of Xenopus laevis against Batrachochytrium dendrobatidis

Mink, Jonathan W.

doi:10.2741/e8

Cited by 17 publications

(22 citation statements)

References 122 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Two previous studies attempted to immunize frogs systemically through injections and did not find evidence of acquired protection against Bd 21,26 , suggesting that the approach used in our study, exposure by way of the skin, might be critical for induction of acquired resistance. Consistent with this proposition are studies suggesting that the adaptive immune system of amphibians responds to Bd.…”

mentioning

confidence: 58%

“…In summary, despite the immunosuppressive effects of Bd 7–9 , the net effect of previous exposures to and clearances of Bd, across three studies and three species (B. quercicus, O. septentrionalis, L. booroolongensis), was to reduce Bd prevalence or abundance on frogs. Differences in the strength of this net effect (immunosuppression + acquired resistance) or variation in pathogenicity across Bd strains might explain host variation in susceptibility to Bd 21,26 .…”

mentioning

confidence: 99%

See 1 more Smart Citation

Amphibians acquire resistance to live and dead fungus overcoming fungal immunosuppression

McMahon

Sears

Venesky

et al. 2014

Nature

204

205

View full text Add to dashboard Cite

Emerging fungal pathogens pose a greater threat to biodiversity than any other parasitic group1, causing declines of many taxa, including bats, corals, bees, snakes and amphibians1–4. Currently, there is little evidence that wild animals can acquire resistance to these pathogens5. Batrachochytrium dendrobatidis is a pathogenic fungus implicated in the recent global decline of amphibians6. Here we demonstrate that three species of amphibians can acquire behavioural or immunological resistance to B. dendrobatidis. Frogs learned to avoid the fungus after just one B. dendrobatidis exposure and temperature-induced clearance. In subsequent experiments in which B. dendrobatidis avoidance was prevented, the number of previous exposures was a negative predictor of B. dendrobatidis burden on frogs and B. dendrobatidis-induced mortality, and was a positive predictor of lymphocyte abundance and proliferation. These results suggest that amphibians can acquire immunity to B. dendrobatidis that overcomes pathogen-induced immunosuppression7–9 and increases their survival. Importantly, exposure to dead fungus induced a similar magnitude of acquired resistance as exposure to live fungus. Exposure of frogs to B. dendrobatidis antigens might offer a practical way to protect pathogen-naive amphibians and facilitate the reintroduction of amphibians to locations in the wild where B. dendrobatidis persists. Moreover, given the conserved nature of vertebrate immune responses to fungi5 and the fact that many animals are capable of learning to avoid natural enemies10, these results offer hope that other wild animal taxa threatened by invasive fungi might be rescued by management approaches based on herd immunity.

show abstract

mentioning

confidence: 58%

mentioning

confidence: 99%

Amphibians acquire resistance to live and dead fungus overcoming fungal immunosuppression

McMahon

Sears

Venesky

et al. 2014

Nature

204

205

View full text Add to dashboard Cite

show abstract

“…Studies in the model amphibian X. laevis indicate T-cell mediated responses begin approximately 14 d post exposure [16]. Therefore 4 wks was considered sufficient time for priming an adaptive response via clonal expansion.…”

Section: Methodsmentioning

confidence: 99%

“…Intensive vaccination could buy time for the evolution of resistance or tolerance to infection by maintaining population size and genetic diversity in the face of extirpation due to small population bottlenecks [9], [16]. Manipulating adaptive immunity through vaccination or inoculation has been successful in combating numerous diseases of domestic and wild animals as well as humans.…”

Section: Introductionmentioning

confidence: 99%

“…Subcutaneous or intraperitoneal injection less effectively stimulate epidermal antigen presenting cells leading potentially to a systemic immune response, rather than targeting the skin where Bd infection naturally occurs [16]. Stimulating this epidermal response may require topical exposure to live Bd to stimulate the normal route of infection and ensure appropriate epitopes are available to be recognized by the immune system [25].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Prior Infection Does Not Improve Survival against the Amphibian Disease Chytridiomycosis

et al. 2013

View full text Add to dashboard Cite

Many amphibians have declined globally due to introduction of the pathogenic fungus Batrachochytrium dendrobatidis (Bd). Hundreds of species, many in well-protected habitats, remain as small populations at risk of extinction. Currently the only proven conservation strategy is to maintain species in captivity to be reintroduced at a later date. However, methods to abate the disease in the wild are urgently needed so that reintroduced and wild animals can survive in the presence of Bd. Vaccination has been widely suggested as a potential strategy to improve survival. We used captive-bred offspring of critically endangered booroolong frogs (Litoria booroolongensis) to test if vaccination in the form of prior infection improves survival following re exposure. We infected frogs with a local Bd isolate, cleared infection after 30 days (d) using itraconazole just prior to the onset of clinical signs, and then re-exposed animals to Bd at 110 d. We found prior exposure had no effect on survival or infection intensities, clearly showing that real infections do not stimulate a protective adaptive immune response in this species. This result supports recent studies suggesting Bd may evade or suppress host immune functions. Our results suggest vaccination is unlikely to be useful in mitigating chytridiomycosis. However, survival of some individuals from all experimental groups indicates existence of protective innate immunity. Understanding and promoting this innate resistance holds potential for enabling species recovery.

show abstract

A Trial of Scheduled Deep Brain Stimulation for Tourette Syndrome

Okun¹,

Foote²,

Wu³

et al. 2013

JAMA Neurol

View full text Add to dashboard Cite

To collect the information necessary to design the methods and outcome variables for a larger trial of scheduled deep brain stimulation (DBS) for Tourette syndrome. Design: We performed a small National Institutes of Health-sponsored clinical trials planning study of the safety and preliminary efficacy of implanted DBS in the bilateral centromedian thalamic region. The study used a cranially contained constant-current device and a scheduled, rather than the classic continuous, DBS paradigm. Baseline vs 6-month outcomes were collected and analyzed. In addition, we compared acute scheduled vs acute continuous vs off DBS. Setting: A university movement disorders center. Patients: Five patients with implanted DBS. Main Outcome Measure: A 50% improvement in the Yale Global Tic Severity Scale (YGTSS) total score. Results: Participating subjects had a mean age of 34.4 (range, 28-39) years and a mean disease duration of 28.8 years. No significant adverse events or hardware-related issues occurred. Baseline vs 6-month data revealed that reductions in the YGTSS total score did not achieve the prestudy criterion of a 50% improvement in the YGTSS total score on scheduled stimulation settings. However, statistically significant improvements were observed in the YGTSS total score (mean [SD] change, −17.8 [9.4]; P=.01), impairment score (−11.3 [5.0]; P=.007), and motor score (−2.8 [2.2]; P=.045); the Modified Rush Tic Rating Scale Score total score (−5.8 [2.9]; P =.01); and the phonic tic severity score (−2.2 [2.6]; P=.04). Continuous, off, and scheduled stimulation conditions were assessed blindly in an acute experiment at 6 months after implantation. The scores in all 3 conditions showed a trend for improvement. Trends for improvement also occurred with continuous and scheduled conditions performing better than the off condition. Tic suppression was commonly seen at ventral (deep) contacts, and programming settings resulting in tic suppression were commonly associated with a subjective feeling of calmness. Conclusions: This study provides safety and proof of concept that a scheduled DBS approach could improve motor and vocal tics in Tourette syndrome. Refinements in neurostimulator battery life, outcome measure selection, and flexibility in programming settings can be used to enhance outcomes in a future larger study. Scheduled stimulation holds promise as a potential first step for shifting movement and neuropsychiatric disorders toward more responsive neuromodulation approaches.

show abstract

Immune defenses of Xenopus laevis against Batrachochytrium dendrobatidis

Cited by 17 publications

References 122 publications

Amphibians acquire resistance to live and dead fungus overcoming fungal immunosuppression

Amphibians acquire resistance to live and dead fungus overcoming fungal immunosuppression

Prior Infection Does Not Improve Survival against the Amphibian Disease Chytridiomycosis

A Trial of Scheduled Deep Brain Stimulation for Tourette Syndrome

Contact Info

Product

Resources

About