scholarly journals Immunity against Helminths: Interactions with the Host and the Intercurrent Infections

2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
Emmanuelle Moreau ◽  
Alain Chauvin

Helminth parasites are of considerable medical and economic importance. Studies of the immune response against helminths are of great interest in understanding interactions between the host immune system and parasites. Effector immune mechanisms against tissue-dwelling helminths and helminths localized in the lumen of organs, and their regulation, are reviewed. Helminth infections are characterized by an association of Th2-like and Treg responses. Worms are able to persist in the host and are mainly responsible for chronic infection despite a strong immune response developed by the parasitized host. Two types of protection against the parasite, namely, premune and partial immunities, have been described. Immune responses against helminths can also participate in pathogenesis. Th2/Treg-like immunomodulation allows the survival of both host and parasite by controlling immunopathologic disorders and parasite persistence. Consequences of the modified Th2-like responses on co-infection, vaccination, and inflammatory diseases are discussed.

2014 ◽  
Vol 2014 ◽  
pp. 1-19 ◽  
Author(s):  
Víctor H. Salazar-Castañon ◽  
Martha Legorreta-Herrera ◽  
Miriam Rodriguez-Sosa

More than one-third of the world’s population is infected with one or more helminthic parasites. Helminth infections are prevalent throughout tropical and subtropical regions where malaria pathogens are transmitted. Malaria is the most widespread and deadliest parasitic disease. The severity of the disease is strongly related to parasite density and the host’s immune responses. Furthermore, coinfections between both parasites occur frequently. However, little is known regarding how concomitant infection with helminths andPlasmodiumaffects the host’s immune response. Helminthic infections are frequently massive, chronic, and strong inductors of a Th2-type response. This implies that infection by such parasites could alter the host’s susceptibility to subsequent infections byPlasmodium. There are a number of reports on the interactions between helminths andPlasmodium; in some, the burden ofPlasmodiumparasites increased, but others reported a reduction in the parasite. This review focuses on explaining many of these discrepancies regarding helminth-Plasmodiumcoinfections in terms of the effects that helminths have on the immune system. In particular, it focuses on helminth-induced immunosuppression and the effects of cytokines controlling polarization toward the Th1 or Th2 arms of the immune response.


2020 ◽  
Vol 21 (22) ◽  
pp. 8729 ◽  
Author(s):  
Chih-Fan Yeh ◽  
Ying-Hsien Chen ◽  
Sheng-Fu Liu ◽  
Hsien-Li Kao ◽  
Ming-Shiang Wu ◽  
...  

Inflammation is the key for the initiation and progression of atherosclerosis. Accumulating evidence has revealed that an altered gut microbiome (dysbiosis) triggers both local and systemic inflammation to cause chronic inflammatory diseases, including atherosclerosis. There have been some microbiome-relevant pro-inflammatory mechanisms proposed to link the relationships between dysbiosis and atherosclerosis such as gut permeability disruption, trigger of innate immunity from lipopolysaccharide (LPS), and generation of proatherogenic metabolites, such as trimethylamine N-oxide (TMAO). Meanwhile, immune responses, such as inflammasome activation and cytokine production, could reshape both composition and function of the microbiota. In fact, the immune system delicately modulates the interplay between microbiota and atherogenesis. Recent clinical trials have suggested the potential of immunomodulation as a treatment strategy of atherosclerosis. Here in this review, we present current knowledge regarding to the roles of microbiota in contributing atherosclerotic pathogenesis and highlight translational perspectives by discussing the mutual interplay between microbiota and immune system on atherogenesis.


1970 ◽  
Vol 1 (1) ◽  
pp. 13-19
Author(s):  
Sheikh Mohammad Fazle Akbar ◽  
Md Sakirul Islam Khan ◽  
Shunji Mishiro

Chronic viral infections represent major challenges in contemporary medicine, virology and pharmacology. The virus-bearing hosts are commonly found in every parts of the world and it is extremely difficult to manage these patients. In addition, considerable numbers of these patients develop progressive diseases and severe complications. Finally, most of these patients act as permanent reservoirs of virus. Understandings of viral life cycle during the last decade of 20th century and the first decade of 21st century have allowed development of hundreds of antiviral agents for different diseases. But, the clinical efficacy of these drugs is not yet satisfactory. In addition, virologists have provided conclusive evidences suggesting that eradication of most chronic virus from infected hosts may an unachievable goal. In this context, it is essential to develop alternative, novel, and evidence-based therapeutic maneuver for these patients. Manipulation of host immune system may be one of these approaches. We would discuss about scopes, limitations, and strategies for manipulation for controlling of chronic viral infections. The primary function of the host's immune system is to mount responses that protect the individual from various microbial infections including viruses. Host's immune responses also control the spread and virulence of the viruses [1]. This is applicable to viruses that cause acute infection. After entering the hosts, these viruses are localized in host's tissues, proliferate and induce antiviral immunity. These cellular events may cause damage and destruction of tissues and the host exhibit features of acute inflammatory diseases. However, the viruses are either almost completely eliminated from the hosts or adequately controlled in situ by host's immune systems. However, chronic infection is established by many viruses because the hosts induce improper and uncoordinated immune responses against these viruses. Most viruses cause persistent infection by evading the host immune surveillance mechanism. Both virus-related factors and host-dependent factors are primarily responsible for viral persistency in subjects with chronic viral infections.    doi: 10.3329/blj.v1i1.2620 Bangladesh Liver Journal Vol.1(1) 2009 p.13-19 


2021 ◽  
Author(s):  
Faustina Pappoe ◽  
Samuel Victor Nuvor

Immune responses of the host to any infectious agents vary in controlling the pathogens. The process begins by the entry of microorganisms into the host to initiate host immune response to understand the type of microorganisms and react accordingly for possible elimination of the organisms. In some cases the host co-exists with the pathogens or unable to effectively deal with them leading to disease condition. Thus, the pathogens establish, multiply and cause disease. The review considered the mode of acquisition of infection, pathogenesis and immune responses to microbial infection. Other areas included the enhancement of immune responses to control infection, immune responses of the host under drug treatment and the control of microbial infection. The understanding of the relationship between infectious microbes and the host immune system leading to protective immunity or disease state will give much information about treatment and controlling of microbial infection in our environment.


mBio ◽  
2013 ◽  
Vol 4 (1) ◽  
Author(s):  
Teresa R. O'Meara ◽  
Stephanie M. Holmer ◽  
Kyla Selvig ◽  
Fred Dietrich ◽  
J. Andrew Alspaugh

ABSTRACTInfectious microorganisms often play a role in modulating the immune responses of their infected hosts. We demonstrate thatCryptococcus neoformanssignals through the Rim101 transcription factor to regulate cell wall composition and the host-pathogen interface. In the absence of Rim101,C. neoformansexhibits an altered cell surface in response to host signals, generating an excessive and ineffective immune response that results in accelerated host death. This host immune response to therim101Δ mutant strain is characterized by increased neutrophil influx into the infected lungs and an altered pattern of host cytokine expression compared to the response to wild-type cryptococcal infection. To identify genes associated with the observed phenotypes, we performed whole-genome RNA sequencing experiments under capsule-inducing conditions. We defined the downstream regulon of the Rim101 transcription factor and determined potential cell wall processes involved in the capsule attachment defects and altered mechanisms of virulence in therim101Δ mutant. The cell wall generates structural stability for the cell and allows the attachment of surface molecules such as capsule polysaccharides. In turn, the capsule provides an effective mask for the immunogenic cell wall, shielding it from recognition by the host immune system.IMPORTANCECryptococcus neoformansis an opportunistic human pathogen that is a significant cause of death in immunocompromised individuals. There are two major causes of death due to this pathogen: meningitis due to uncontrolled fungal proliferation in the brain in the face of a weakened immune system and immune reconstitution inflammatory syndrome characterized by an overactive immune response to subclinical levels of the pathogen. In this study, we examined howC. neoformansuses the conserved Rim101 transcription factor to specifically remodel the host-pathogen interface, thus regulating the host immune response. These studies explored the complex ways in which successful microbial pathogens induce phenotypes that ensure their own survival while simultaneously controlling the nature and degree of the associated host response.


F1000Research ◽  
2018 ◽  
Vol 7 ◽  
pp. 1685 ◽  
Author(s):  
Pedro H. Gazzinelli-Guimaraes ◽  
Thomas B. Nutman

Helminth parasites are complex metazoans that belong to different taxonomic families but that collectively share the capacity to downregulate the host immune response directed toward themselves (parasite-specific immunoregulation). During long-standing chronic infection, these helminths appear able to suppress immune responses to bystander pathogens/antigens and atopic, autoimmune, and metabolic disorders. Helminth-induced immunoregulation occurs through the induction of regulatory T cells or Th2-type cells (or both). However, secreted or excreted parasite metabolites, proteins, or extracellular vesicles (or a combination of these) may also directly induce signaling pathways in host cells. Therefore, the focus of this review will be to highlight recent advances in understanding the immune responses to helminth infection, emphasizing the strategies/molecules and some of the mechanisms used by helminth parasites to modulate the immune response of their hosts.


QJM ◽  
2020 ◽  
Vol 113 (Supplement_1) ◽  
Author(s):  
H S Elwakil

Abstract Intestinal helminths are potent regulators of their host’s immune system and can protect against Inflammatory bowel disease. This anti-inflammatory activity remains largely unknown. Is it purely intrinsic to helminths, or whether it also involved cross interaction with the local microbiota? Microbiota and helminths have coevolved within the mammalian host. Both have common strategies of establishing a new homeostasis in the host intestinal tract. These strategies include regulating host immunity to permit their survival through the induction of suppressive regulatory T cells ( Tregs ). Also, Short-Chain Fatty Acids (SCFAs) may be a possible another common pathway shared by microbiota and helminths. SCFAs are microbial metabolite that are derived from microbial fermentation of dietary fibers in the colon. Similarly, some helminth infection leads to SCFAs elevation in human. SCFAs can potentiate T regs generation and IL- 10 production in the periphery. Dissecting the multidirectional interactions among intestinal microbes, helminth parasites and their host immune system will hopefully enable the design of new therapeutic strategies to treat metabolic and inflammatory diseases


2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Tian-Yu Lei ◽  
Ying-Ze Ye ◽  
Xi-Qun Zhu ◽  
Daniel Smerin ◽  
Li-Juan Gu ◽  
...  

AbstractThrough considerable effort in research and clinical studies, the immune system has been identified as a participant in the onset and progression of brain injury after ischaemic stroke. Due to the involvement of all types of immune cells, the roles of the immune system in stroke pathology and associated effects are complicated. Past research concentrated on the functions of monocytes and neutrophils in the pathogenesis of ischaemic stroke and tried to demonstrate the mechanisms of tissue injury and protection involving these immune cells. Within the past several years, an increasing number of studies have elucidated the vital functions of T cells in the innate and adaptive immune responses in both the acute and chronic phases of ischaemic stroke. Recently, the phenotypes of T cells with proinflammatory or anti-inflammatory function have been demonstrated in detail. T cells with distinctive phenotypes can also influence cerebral inflammation through various pathways, such as regulating the immune response, interacting with brain-resident immune cells and modulating neurogenesis and angiogenesis during different phases following stroke. In view of the limited treatment options available following stroke other than tissue plasminogen activator therapy, understanding the function of immune responses, especially T cell responses, in the post-stroke recovery period can provide a new therapeutic direction. Here, we discuss the different functions and temporal evolution of T cells with different phenotypes during the acute and chronic phases of ischaemic stroke. We suggest that modulating the balance between the proinflammatory and anti-inflammatory functions of T cells with distinct phenotypes may become a potential therapeutic approach that reduces the mortality and improves the functional outcomes and prognosis of patients suffering from ischaemic stroke.


2020 ◽  
Vol 10 (2) ◽  
pp. 305-314
Author(s):  
I. N. Zhilinskaya

A comparative analysis on search for amino acid sequences in viral proteins causing respiratory infections (or respiratory infections syndrome) homologous to amino acid sequences from some human immune proteins was performed. The following viruses were used for comparative computer analysis: coronavirus (SARS-CoV), serotype C subgroup adenovirus C (adenoid 71 strain), measles virus (ICHINOSE-BA strain), rubella (Therien strain) and respiratory syncytial (B1 strain) virus. The search for homologous sequences in viral and human immune proteins was carried out by computer comparison of 12 amino acid fragments, which were assigned as homologous at identity in ≥ 8 positions. The data obtained showed that viral proteins contained homologous motifs in several host immune proteins involved in regulating both the inflammatory response and immune response. Mechanistically, all viruses studied were characterized by sequences homologous to host immune proteins such as complement system proteins, integrins, apoptosis inhibitory proteins, interleukins, and toll-like receptors. Such cellular proteins are actively involved in regulating host inflammatory process and immune response formation. Upon that, a set of host immune proteins, to which homologous fragments were found in viral proteins, was individual for each virus. Interestingly, the largest amount of homologous fragments (up to 20) was mainly concentrated in viral proteins with polymerase and protease activity suggesting that these proteins apart to their major role were involved in production of viral nucleic acids and might participate in regulating host immune system. Envelope, internal and non-structural viral proteins, homologous fragments were detected in much smaller quantities (from 1 to 4). In addition, two fragments homologous to various motifs of the same cellular protein were detected in some viral proteins. Thus, the data obtained further support our understanding that signs of immune system disorders in viral infections can result from multi-layered processes associated with modulation of host innate and adaptive immune system, and open up new approaches to study interaction of viruses with host immune system and identify new functions of viral proteins.


2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 181-181
Author(s):  
Martin Lessard ◽  
Mylène Blais ◽  
Guylaine Talbot ◽  
J Jacques Matte ◽  
Ann Letellier ◽  
...  

Abstract Lactation, feeding conditions, microbial interventions and piglet growth in the first few weeks of life have important impact on the intestinal microbiota establishment and immune system development of piglets. Indeed, colostrum and milk contain various bioactive components such as immune factors, antimicrobial peptides and oligosaccharides that contribute to maintain intestinal homeostasis and regulate interactions between microbiota and host immune system. Recent results revealed that low birth weight piglet (LBWP) with poor weight gain during the first two weeks of life develop different intestinal microbiota and immune response profiles compared to high BWP (HBWP) littermates. Consequently, piglets within litters may have different resilience to infections after weaning and benefit from feed additives in a specific manner. A study has been performed to evaluate the potential of bovine colostrum extract (BC) as replacement to plasma proteins for improving gut health and resilience to Salmonella infection in piglets. Results revealed that in weaned piglets fed BC, intestinal microbiota was differently modulated and bacterial dysbiosis induced by Salmonella was restored faster. Moreover, expression of genes involved in innate immunity such as β-defensin-2 and glutathione peroxidase-2 was respectively down- and up-regulated in BC fed piglets. A combination of dietary supplementation with BC, cupper and vitamins A and D has also been tested in LBWP and HBWP, and there is clear evidence that BC in combination with other feed additives promote growth and gut health in both LBWP and HBWP. The porcine intestinal epithelial cell line IPEC-J2 was used to better understand the functional properties of BC. Results indicated that BC improves wound healing, enhances barrier function and modulates the expression of several genes involved in innate immune response. Finally, as microbial intervention, the potential of fecal transplantation to modulate intestinal microbiota and immune system development of piglets is under investigation and will be discussed.


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