scholarly journals Activation of host constitutive immune defence by an intestinal trypanosome parasite of bumble bees

Parasitology ◽  
2003 ◽  
Vol 126 (3) ◽  
pp. 253-260 ◽  
Author(s):  
M. J. F. BROWN ◽  
Y. MORET ◽  
P. SCHMID-HEMPEL
Keyword(s):  
Immune System ◽  
Bombus Terrestris ◽  
Parasitic Infection ◽  
Bumble Bees ◽  
Host Immune System ◽  
Immune Defence ◽  
Important Species ◽  
Crithidia Bombi ◽  
Resource Stress ◽  
Host Parasite

Many parasites, including important species that affect humans and livestock, must survive the harsh environment of insect guts to complete their life-cycle. Hence, understanding how insects protect themselves against such parasites has immediate practical implications. Previously, such protection has been thought to consist mainly of mechanical structures and the action of lectins. However, recently it has become apparent that gut infections may interact with the host immune system in more complex ways. Here, using bumble bees, Bombus terrestris and their non-invasive gut trypanosome, Crithidia bombi, as a model system we investigated the effects of parasitic infection, host resources and the duration of infections on the host immune system. We found that infection doubled standing levels of immune defence in the haemolymph (the constitutive pro-phenoloxidase system), which is used as a first, general defence against parasites. However, physical separation of the parasite from the haemolymph suggests the presence of a messenger system between the gut and the genes that control the pro-phenoloxidase system. Surprisingly, we found no direct effect of host resource-stress or duration of the infection on the immune system. Our results suggest a novel and tactical response of insects to gut infections, demonstrating the complexity of such host–parasite systems.

Immunocompetence in workers of a social insect, Bombus terrestris L., in relation to foraging activity and parasitic infection

2000 ◽  
Vol 78 (6) ◽  
pp. 1060-1066 ◽  
Author(s):  
Claudie Doums ◽  
Paul Schmid-Hempel
Keyword(s):  
Immune Response ◽  
Immune Responses ◽  
Intestinal Parasite ◽  
Bombus Terrestris ◽  
Parasitic Infection ◽  
General Mechanism ◽  
Immune Defence ◽  
Foraging Activity ◽  
Natural Conditions ◽  
Crithidia Bombi

The immune system is a general mechanism that reduces the fitness cost of parasitism. In this study, we examined variation in immune responses under natural conditions in the bumblebee Bombus terrestris. Using 14 colonies reared in the field, we compared the immune response to an artificial implant between workers that could or could not forage (86 control and 91 nonforaging workers). Foraging activity was prevented by cutting a large part of the wings. As expected, control workers had lower immune responses than nonforaging workers in 10 of 14 colonies. Overall, the treatment effect was significant even though weak, suggestive of a trade-off between immune defence and foraging activity. We also examined the environmental factors that might covary with the immune response in workers. The immune response significantly decreased in workers that were naturally infected by the intestinal parasite Crithidia bombi and increased with a measure of colony success, the maximum number of workers. These correlations suggest that the strength of immune responses reflects individual, and hence colony condition.

scholarly journals Immune response and gut microbial community structure in bumblebees after microbiota transplants

2016 ◽  
Vol 283 (1831) ◽  
pp. 20160312 ◽  
Author(s):  
Kathrin Näpflin ◽  
Paul Schmid-Hempel
Keyword(s):  
Immune Response ◽  
Immune System ◽  
Microbial Community ◽  
Bombus Terrestris ◽  
Microbial Community Composition ◽  
Host Immune System ◽  
Susceptible Host ◽  
Protective Function ◽  
Crithidia Bombi ◽  
Gut Microbial Community

Microbial communities are a key component of host health. As the microbiota is initially ‘foreign’ to a host, the host's immune system should respond to its acquisition. Such variation in the response should relate not only to host genetic background, but also to differences in the beneficial properties of the microbiota. However, little is known about such interactions. Here, we investigate the gut microbiota of the bumblebee, Bombus terrestris , which has a protective function against the bee's natural trypanosome gut parasite, Crithidia bombi . We transplanted ‘resistant’ and ‘susceptible’ microbiota into ‘resistant’ and ‘susceptible’ host backgrounds, and studied the activity of the host immune system. We found that bees from different resistance backgrounds receiving a microbiota differed in aspects of their immune response. At the same time, the elicited immune response also depended on the received microbiota's resistance phenotype. Furthermore, the microbial community composition differed between microbiota resistance phenotypes (resistant versus susceptible). Our results underline the complex feedback between the host's ability to potentially exert selection on the establishment of a microbial community and the influence of the microbial community on the host immune response in turn.

scholarly journals Microbiome Structure Influences Infection by the Parasite Crithidia bombi in Bumble Bees

2018 ◽  
Vol 84 (7) ◽  
Author(s):  
Blair K. Mockler ◽  
Waldan K. Kwong ◽  
Nancy A. Moran ◽  
Hauke Koch
Keyword(s):  
Gut Microbiota ◽  
Bombus Terrestris ◽  
Bacterial Load ◽  
Bumble Bees ◽  
Bumble Bee ◽  
Bacterial Populations ◽  
Important Species ◽  
Content Type ◽  
Crithidia Bombi ◽  
Microbiome Diversity

ABSTRACT Recent declines in bumble bee populations are of great concern and have prompted critical evaluations of the role of pathogen introductions and host resistance in bee health. One factor that may influence host resilience when facing infection is the gut microbiota. Previous experiments with Bombus terrestris , a European bumble bee, showed that the gut microbiota can protect against Crithidia bombi , a widespread trypanosomatid parasite of bumble bees. However, the particular characteristics of the microbiome responsible for this protective effect have thus far eluded identification. Using wild and commercially sourced Bombus impatiens , an important North American pollinator, we conducted cross-wise microbiota transplants to naive hosts of both backgrounds and challenged them with a Crithidia parasite. As with B. terrestris , we find that microbiota-dependent protection against Crithidia operates in B. impatiens . Lower Crithidia infection loads were experimentally associated with high microbiome diversity, large gut bacterial populations, and the presence of Apibacter , Lactobacillus Firm-5, and Gilliamella spp. in the gut community. These results indicate that even subtle differences between gut community structures can have a significant impact on a microbiome's ability to defend against parasite infections. IMPORTANCE Many wild bumble bee populations are under threat due to human activity, including through the introduction of pathogens via commercially raised bees. Recently, it was found that the bumble bee gut microbiota can help defend against a common parasite, Crithidia bombi , but the particular factors contributing to this protection are unknown. Using both wild and commercially raised bees, we conducted microbiota transplants to show that microbiome diversity, total gut bacterial load, and the presence of certain core members of the microbiota may all impact bee susceptibility to Crithidia infection. Bee origin (genetic background) was also a factor. Finally, by examining this phenomenon in a previously uninvestigated bee species, our study demonstrates that microbiome-mediated resistance to Crithidia is conserved across multiple bumble bee species. These findings highlight how intricate interactions between hosts, microbiomes, and parasites can have wide-ranging consequences for the health of ecologically important species.

Use of immunological manipulations in studying genetically controlled responses to Leishmania donovani infection in mice

Parasitology ◽  
1984 ◽  
Vol 88 (4) ◽  
pp. 677-679 ◽  
Author(s):  
Jenefer M. Blackwell
Keyword(s):  
Immune System ◽  
Leishmania Donovani ◽  
Inbred Mouse ◽  
Parasitic Infection ◽  
Preceding Paper ◽  
Mouse Strains ◽  
Host Immune System ◽  
Inbred Mouse Strains

In the preceding paper Howard (p. 665) has given a very elegant presentation on ways in which the host immune system may be manipulated to provide valuable information about immunoregulation of parasitic infection in vivo. In our laboratory we have used some of the same manoeuvres to study immunoregulation of genetically controlled responses to Leishmania donovani infection in inbred mouse strains (Ulczak & Blackwell, 1983; Crocker, Blackwell & Bradley, 1984). As has been Howard's experience, the results obtained have not always been as one might have predicted at the outset.

scholarly journals A Mathematical Model of Continuous HIV Mutations Eluding Immune Defence

2002 ◽  
Vol 4 (4) ◽  
pp. 241-249 ◽  
Author(s):  
D. P. Wilson ◽  
D. L. S. McElwain
Keyword(s):  
Mathematical Model ◽  
Immune System ◽  
Untreated Patient ◽  
Deterministic Model ◽  
Viral Population ◽  
Host Immune System ◽  
Immune Defence ◽  
Threshold Theory

We develop a description of HIV mutations based upon a continuum representation of the fitness of the virus, including the interaction of the virus with both specific Th1 lymphocytes as well as cross-reactive cells. This deterministic model allows a straightforward measure of the diversity of viral population and reproduces the observed increase in diversity as the disease progresses in an untreated patient. We use the diversity threshold theory, extending the modelling to track mutations on a continuum. When the diversity threshold is exceeded, the host immune system collapses.

ON A KINETIC (CELLULAR) THEORY FOR COMPETITION BETWEEN TUMORS AND THE HOST IMMUNE SYSTEM

1996 ◽  
Vol 04 (04) ◽  
pp. 479-502 ◽  
Author(s):  
N. BELLOMO ◽  
L. PREZIOSI ◽  
G. FORNI
Keyword(s):  
Immune System ◽  
Statistical Mechanics ◽  
Evolution Equations ◽  
Kinetic Modelling ◽  
Host Immune System ◽  
Cellular Interactions ◽  
Immune Defence ◽  
Qualitative Properties ◽  
Defence System ◽  
The One

This paper deals with a kinetic modelling of the cellular dynamics of tumors interacting with an active immune defence system. The analysis starts from a detailed modelling of the cellular interactions and follows with the derivation of evolution equations in a framework similar to the one of nonlinear statistical mechanics. A discussion about the qualitative properties of the model and on the possibility of its application in immunology is proposed in the last part of the paper.

Role of the surface coat of Romanomermis culicivorax in immune evasion

Nematology ◽  
2007 ◽  
Vol 9 (1) ◽  
pp. 17-24 ◽  
Author(s):  
Edward Platzer ◽  
Randy Gaugler ◽  
Muhammad Shamseldean
Keyword(s):  
Immune System ◽  
Immune Evasion ◽  
Immune Reaction ◽  
Parasitic Nematodes ◽  
Broad Host Range ◽  
Host Immune System ◽  
Surface Coat ◽  
Mermithid Nematode ◽  
Host Parasite

AbstractInteractions of the mermithid nematode Romanomermis culicivorax with the immune system of mosquito larvae were examined by scanning electron microscopy. The host immune system rapidly recognised invading parasites, as granulocytes and discharged granules were observed attached to parasitic nematodes within 5 min. Melanin deposition was infrequently observed. As a counter measure, the parasites secreted and shed an extracellular surface coat which aided immune evasion. During the first 4 days of infection, when parasite growth was limited, the coat served as a disposable, renewable barrier between parasite and host that was intermittently shed to cleanse the nematode of adhering host immune products. In the later infection phase the parasite grew rapidly and was beyond the effect of the depleted host immune response. The broad host range of R. culcivorax within culicines may be partly a function of the nonspecific defence it mounts against the host immune system. In summary, shedding of the surface coat is an adaptive counter response by R. culicivorax to the mosquito immune reaction to infection and provides a classic example of host-parasite coevolution.

scholarly journals Immune response impairs learning in free-flying bumble-bees

2008 ◽  
Vol 4 (5) ◽  
pp. 479-481 ◽  
Author(s):  
A Alghamdi ◽  
L Dalton ◽  
A Phillis ◽  
E Rosato ◽  
E.B Mallon
Keyword(s):  
Immune Response ◽  
Immune System ◽  
Mate Choice ◽  
Direct Effect ◽  
Predator Avoidance ◽  
Bombus Terrestris ◽  
Bumble Bees ◽  
Learning Performance ◽  
Direct Effects ◽  
Learning Abilities

Parasites can influence different host behaviours including foraging, mate choice and predator avoidance. Several recent papers have shown reduced learning abilities in infected insects. However, it is difficult to separate the effects of the immune response from the direct effects of the parasite. Using a free-flying learning paradigm, this paper shows that learning performance is impaired in bumble-bees ( Bombus terrestris ) that are not infected but whose immune system is stimulated non-pathogenically. This demonstrates that before it is assumed that a parasite has a direct effect on a host's behaviour, the effect of the immune response stimulated by the parasite must first be quantified.

Mathematical models of parasite responses to host immune defences

Parasitology ◽  
1997 ◽  
Vol 115 (7) ◽  
pp. 155-167 ◽  
Author(s):  
R. ANTIA ◽  
M. LIPSITCH
Keyword(s):  
Immune System ◽  
Simple Model ◽  
Acute Infection ◽  
Multiple Infections ◽  
Host Immune System ◽  
Host Genotype ◽  
Immune Mediated ◽  
Host Parasite ◽  
Immune Defences ◽  
Rates Of Growth

We examine the evolution of microparasites in response to the immune system of vertebrate hosts. We first describe a simple model for an acute infection. This model suggests that the within-host dynamics of the microparasite will be a ‘race’ between parasite multiplication and a clonally expanding response by the host immune system, resulting either in immune-mediated clearance or host death. In this very simple model, in which there is only a single parasite and host genotype, maximum transmission is obtained by parasites with intermediate rates of growth (and virulence). We examine how these predictions depend on key assumptions about the parasite and the host, and consider how this model may be expanded to incorporate the effect of additional complexities such as host–parasite co-evolution, host polymorphism, and multiple infections.

scholarly journals Helminth Glycans at the Host-Parasite Interface and Their Potential for Developing Novel Therapeutics

2022 ◽  
Vol 8 ◽  
Author(s):  
Myrna J. M. Bunte ◽  
Arjen Schots ◽  
Jan E. Kammenga ◽  
Ruud H. P. Wilbers
Keyword(s):  
Immune System ◽  
Immune Cells ◽  
Helminth Infection ◽  
Host Immune System ◽  
Lewis X ◽  
Novel Therapeutics ◽  
Antigenic Properties ◽  
Parasitic Worms ◽  
Host Parasite

Helminths are parasitic worms that have successfully co-evolved with their host immune system to sustain long-term infections. Their successful parasitism is mainly facilitated by modulation of the host immune system via the release of excretory-secretory (ES) products covered with glycan motifs such as Lewis X, fucosylated LDN, phosphorylcholine and tyvelose. Evidence is accumulating that these glycans play key roles in different aspects of helminth infection including interactions with immune cells for recognition and evasion of host defences. Moreover, antigenic properties of glycans can be exploited for improving the efficacy of anti-helminthic vaccines. Here, we illustrate that glycans have the potential to open new avenues for the development of novel biopharmaceuticals and effective vaccines based on helminth glycoproteins.

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