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

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.

Parasitology ◽  
2003 ◽  
Vol 126 (3) ◽  
pp. 253-260 ◽  
Author(s):  
M. J. F. BROWN ◽  
Y. MORET ◽  
P. SCHMID-HEMPEL

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.


2016 ◽  
Vol 283 (1831) ◽  
pp. 20160312 ◽  
Author(s):  
Kathrin Näpflin ◽  
Paul Schmid-Hempel

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.


2014 ◽  
Vol 281 (1786) ◽  
pp. 20140128 ◽  
Author(s):  
Franziska S. Brunner ◽  
Paul Schmid-Hempel ◽  
Seth M. Barribeau

Parasites infect hosts non-randomly as genotypes of hosts vary in susceptibility to the same genotypes of parasites, but this specificity may be modulated by environmental factors such as nutrition. Nutrition plays an important role for any physiological investment. As immune responses are costly, resource limitation should negatively affect immunity through trade-offs with other physiological requirements. Consequently, nutritional limitation should diminish immune capacity in general, but does it also dampen differences among hosts? We investigated the effect of short-term pollen deprivation on the immune responses of our model host Bombus terrestris when infected with the highly prevalent natural parasite Crithidia bombi . Bumblebees deprived of pollen, their protein source, show reduced immune responses to infection. They failed to upregulate a number of genes, including antimicrobial peptides, in response to infection. In particular, they also showed less specific immune expression patterns across individuals and colonies. These findings provide evidence for how immune responses on the individual-level vary with important elements of the environment and illustrate how nutrition can functionally alter not only general resistance, but also alter the pattern of specific host–parasite interactions.


2016 ◽  
Vol 3 (1) ◽  
Author(s):  
Ashley Shaw

There is controversy about the effects gut-dwelling eugregarine parasites have on their invertebrate hosts. If crickets (Gryllus firmus) apportion resources to reproduction differently in males vs. females, then resources used to mount immune responses to parasites may also differ – especially if the parasites are pathogenic. I investigated the possible differences in immune response between male and female crickets and attempted to determine whether these differences are related to intensity of parasitic infection. To do this, pieces of nylon filament were implanted into the hemocoel of crickets which tested the immune response where hemocytes surround the filament (encapsulation). These responses were compared to intensity of parasitic infection. No statistically significant relationship between sex and melanisation, or sex and parasite load were found. I found that the duration of melanization was negatively correlated to parasite abundance and that there was a positive correlation between body size and parasite number. This result suggests the existence of a relationship between the parasite and host that could be conflicting with sexual selection theory, such as host manipulation by the parasite.


2015 ◽  
Vol 29 (3) ◽  
pp. 119-129 ◽  
Author(s):  
Richard J. Stevenson ◽  
Deborah Hodgson ◽  
Megan J. Oaten ◽  
Luba Sominsky ◽  
Mehmet Mahmut ◽  
...  

Abstract. Both disgust and disease-related images appear able to induce an innate immune response but it is unclear whether these effects are independent or rely upon a common shared factor (e.g., disgust or disease-related cognitions). In this study we directly compared these two inductions using specifically generated sets of images. One set was disease-related but evoked little disgust, while the other set was disgust evoking but with less disease-relatedness. These two image sets were then compared to a third set, a negative control condition. Using a wholly within-subject design, participants viewed one image set per week, and provided saliva samples, before and after each viewing occasion, which were later analyzed for innate immune markers. We found that both the disease related and disgust images, relative to the negative control images, were not able to generate an innate immune response. However, secondary analyses revealed innate immune responses in participants with greater propensity to feel disgust following exposure to disease-related and disgusting images. These findings suggest that disgust images relatively free of disease-related themes, and disease-related images relatively free of disgust may be suboptimal cues for generating an innate immune response. Not only may this explain why disgust propensity mediates these effects, it may also imply a common pathway.


2017 ◽  
pp. 119-124
Author(s):  

Introduction: Intestinal parasite infections werecommonintropical country such as Vietnam. Having good knowledge of parasitic infectious prevention and changing risk behaviors can decrease the infection rate. Objective: To evaluate the parasitic infectious rate in Vinh Thai community before and after being health education and the changing of knowledge of parasitic infectious prevention and risk behaviors. Materials and methods: 60 households in Vinh Thai commune were interviewed their knowledge of parasitic infectious prevention and examined intestinal parasite infection by Kato technique and then trained the knowledge of parasitic infectious prevention. The interview and examination parasite infectiousrate were carried out after 6 months to evaluating their knowledge. Result: Before health education, the rate of intestinal parasite infection was 17.4% with the prevalence of Ascaris lumbricoides, hookworm, whipworm, pinworm, small fluke worm and co-infection with A. lumbricoides - whipworm, hookworm-whipworm were 0.1%; 8.0%; 5.8%; 0.6%; 0.3%; 1.2% and 3.0% respectively. Six months later the rate of intestinal parasite infection was decreased in 12.6% even though not statistical significantly. However, there were no case of small fluke worm and co-infection with hookworm-whipworm. Receiving health education, their knowledge of parasitic infectious prevention was higher significantly but their risk behaviors were not changed so much. Conclusion: Health education can change the rate of parasite infection with higher knowledge of parasitic infectious prevention but it was necessary continuous study to change the risk behaviors. Key words: intestinal parasite, health education


1977 ◽  
Vol 146 (2) ◽  
pp. 571-578 ◽  
Author(s):  
M E Dorf ◽  
J H Stimpfling

The ability of various B10 congenic resistant strains to respond to the alloantigen H-2.2 was tested. High and low antibody-producing strains were distinguished by their anti-H-2.2 hemagglutinating respones. However, these strains do not differ in their ability to respond to these antigenic differences in the mixed lymphocyte culture. The humoral response to the H-2.2 alloantigen was shown to be controlled by two interacting genes localized within the H-2 complex. Thus, F1 hybrids prepared between parental low responder strains could yield high level immune responses. In addition, strains bearing recombinant H-2 haplotypes were used to map the two distinct genes controlling the immune response. The alleles at each locus were shown to be highly polymorphic as evidenced by the asymmetric complementation patterns observed. The restricted interactions of specific alleles was termed coupled complementation. The significance of the results in the terms of mechanisms of Ir gene control are discussed.


2019 ◽  
Vol 20 (21) ◽  
pp. 5493 ◽  
Author(s):  
Meunier ◽  
Chea ◽  
Garrido ◽  
Perchet ◽  
Petit ◽  
...  

Innate lymphoid cells (ILC) are important players of early immune defenses in situations like lymphoid organogenesis or in case of immune response to inflammation, infection and cancer. Th1 and Th2 antagonism is crucial for the regulation of immune responses, however mechanisms are still unclear for ILC functions. ILC2 and NK cells were reported to be both involved in allergic airway diseases and were shown to be able to interplay in the regulation of the immune response. CXCR6 is a common chemokine receptor expressed by all ILC, and its deficiency affects ILC2 and ILC1/NK cell numbers and functions in lungs in both steady-state and inflammatory conditions. We determined that the absence of a specific ILC2 KLRG1+ST2– subset in CXCR6-deficient mice is probably dependent on CXCR6 for its recruitment to the lung under inflammation. We show that despite their decreased numbers, lung CXCR6-deficient ILC2 are even more activated cells producing large amount of type 2 cytokines that could drive eosinophilia. This is strongly associated to the decrease of the lung Th1 response in CXCR6-deficient mice.


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