Salivarian Trypanosomosis Have Adopted Intricate Host-Pathogen Interaction Mechanisms That Ensures Survival Plain Sight of the Adaptive Immune System

Salivarian trypanosomes are extracellular parasites affecting humans, livestock and game animals. Trypanosoma brucei rhodesiense and Trypanosoma brucei gambiense are human infective sub-species of T. brucei causing Human African Trypanosomosis (HAT - sleeping sickness). The related T. b. brucei parasite lacks the resistance to survive in human serum, and only inflicts animal infections. Animal Trypanosomosis (AT) is not restricted to Africa, but is present on all continents. T. congolense and T. vivax are the most widespread pathogenic trypanosomes in sub-Sahara Africa. Trough mechanical transmission, T. vivax has however been introduced into South America. T. evansi is a unique animal trypanosome that is found in vast territories around the world and can cause atypical Human Trypanosomosis (aHT). All salivarian trypanosomes are well adapted to survival inside the host’s immune system. This is not a hostile environment for these parasite, but this is the place where they thrive. Here we provide an overview of the latest insights into the host-parasite interaction and the unique survival strategies allowing trypanosomes to outsmart the immune system. In addition, we review new developments in treatment and diagnosis as well the issues that have hampered the development of field-applicable anti-trypanosome vaccines for the implementation of sustainable disease control.

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Salivarian Trypanosomes Have Adopted Intricate Host-Pathogen Interaction Mechanisms that Ensure Survival in Plain Sight of the Adaptive Immune System

Pathogens ◽

10.3390/pathogens10060679 ◽

2021 ◽

Vol 10 (6) ◽

pp. 679

Author(s):

Stefan Magez ◽

Joar Esteban Pinto Torres ◽

Seoyeon Oh ◽

Magdalena Radwanska

Keyword(s):

Immune System ◽

Trypanosoma Brucei ◽

Adaptive Immune System ◽

Sub Saharan Africa ◽

Survival Strategies ◽

Mechanical Transmission ◽

Sub Saharan ◽

Animal Trypanosomiasis ◽

Host Parasite ◽

Treatment And Diagnosis

Salivarian trypanosomes are extracellular parasites affecting humans, livestock and game animals. Trypanosoma brucei rhodesiense and Trypanosoma brucei gambiense are human infective sub-species of T. brucei causing human African trypanosomiasis (HAT—sleeping sickness). The related T. b. brucei parasite lacks the resistance to survive in human serum, and only inflicts animal infections. Animal trypanosomiasis (AT) is not restricted to Africa, but is present on all continents. T. congolense and T. vivax are the most widespread pathogenic trypanosomes in sub-Saharan Africa. Through mechanical transmission, T. vivax has also been introduced into South America. T. evansi is a unique animal trypanosome that is found in vast territories around the world and can cause atypical human trypanosomiasis (aHT). All salivarian trypanosomes are well adapted to survival inside the host’s immune system. This is not a hostile environment for these parasites, but the place where they thrive. Here we provide an overview of the latest insights into the host-parasite interaction and the unique survival strategies that allow trypanosomes to outsmart the immune system. In addition, we review new developments in treatment and diagnosis as well as the issues that have hampered the development of field-applicable anti-trypanosome vaccines for the implementation of sustainable disease control.

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One day is enough: rapid and specific host–parasite interactions in a stickleback-trematode system

Biology Letters ◽

10.1098/rsbl.2006.0462 ◽

2006 ◽

Vol 2 (3) ◽

pp. 382-384 ◽

Cited By ~ 43

Author(s):

Gisep Rauch ◽

Martin Kalbe ◽

Thorsten B.H Reusch

Keyword(s):

Immune System ◽

Genotypic Variation ◽

Adaptive Immune System ◽

Host Defence ◽

Defence Mechanism ◽

Fish Family ◽

Adaptive Immune ◽

Specific Host ◽

Host Parasite Interactions ◽

Host Parasite

Red Queen models of host–parasite coevolution are based on genotype by genotype host–parasite interactions. Such interactions require a genotype specific host defence and, simultaneously, a genotype specific parasite infectivity. Specificity is defined here as defence or infection ability successful against only a subset of genotypes of the same species. A specific defence depends on detectable genotypic variation on the parasite side and on a host defence mechanism that differentiates between parasite genotypes. In vertebrates, the MHC-based adaptive immune system can provide such a defence mechanism, but it needs at least several days to get fully mounted. In contrast, the innate immune system is immediately ready. The trematode parasite species used here reaches the immunologically protected eye lens of its three-spined stickleback ( Gasterosteus aculeatus ) host within 24 h. Thus, it disappears too fast for the fully mounted MHC-based adaptive immune system. In a complete cross-infection experiment using five fish-families and five parasite-clones, we found for the first time fish-family by parasite-clone interactions in vertebrates, although the parasite was only exposed to the immune system for maximally one day. Such interactions require a fast genotype specific defence, suggesting the importance of other defence mechanisms than the too slow, fully mounted adaptive immune system in vertebrates.

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Editor's cut: DNA cleavage by CRISPR RNA-guided nucleases Cas9 and Cas12a

Biochemical Society Transactions ◽

10.1042/bst20190563 ◽

2019 ◽

Vol 48 (1) ◽

pp. 207-219 ◽

Cited By ~ 2

Author(s):

Thomas Swartjes ◽

Raymond H.J. Staals ◽

John van der Oost

Keyword(s):

Immune System ◽

Genome Editing ◽

Dna Cleavage ◽

Adaptive Immune System ◽

New Developments ◽

Biochemical Characteristics ◽

Base Editing ◽

Dna Cleaving ◽

Adaptive Immune ◽

General Method

Discovered as an adaptive immune system of prokaryotes, CRISPR–Cas provides many promising applications. DNA-cleaving Cas enzymes like Cas9 and Cas12a, are of great interest for genome editing. The specificity of these DNA nucleases is determined by RNA guides, providing great targeting adaptability. Besides this general method of programmable DNA cleavage, these nucleases have different biochemical characteristics, that can be exploited for different applications. Although Cas nucleases are highly promising, some room for improvement remains. New developments and discoveries like base editing, prime editing, and CRISPR-associated transposons might address some of these challenges.

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Preface

Parasitology ◽

10.1017/s0031182098009664 ◽

1997 ◽

Vol 115 (7) ◽

pp. 3-3

Author(s):

M. J. Doenhoff ◽

L. H. Chappell

Keyword(s):

Immune Response ◽

Immune System ◽

T Cell ◽

Molecular Mimicry ◽

Adaptive Immune System ◽

T Cell Subsets ◽

Survival Strategies ◽

Molecular Component ◽

Immunocompetent Host ◽

Adaptive Immune

The papers in this volume draw attention to both new and recent information on the mechanisms employed by infectious pathogens to underpin their survival in the immunocompetent host and to facilitate their transmission between hosts. Classical survival strategies include induction of immuno- suppression, antigenic variety and variation, host antigen sequestration, molecular mimicry, antibody destruction and invasion of cells or privileged sites. To these we can now add novel and diverse mechanisms with which the invader may manipulate the host for its own ends. They range from making use of a single molecular component of the immune system, through more sophisticated mechanisms of evasion to modulation of the immune response in the pathogen's favour, particularly by manipulation of T cell subsets and cytokine fluxes. There are then examples of pure exploitation of the adaptive immune system by the generation of specific humoral and cell-mediated responses that prolong the invader's survival and aid transmission. The order of the chapters in this volume is intended to reflect this increasing level of complexity.It is our hope that the studies described in this multi-disciplinary assemblage of papers will stimulate further research in this important area. We would like to thank all our contributing authors and the anonymous refereees for their commitment and help in seeing this project through to completion.

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