scholarly journals The Probiotic Bacterium Lactobacillus casei Induces Activation of the Gut Mucosal Immune System through Innate Immunity

2006 ◽  
Vol 13 (2) ◽  
pp. 219-226 ◽  
Author(s):  
C. Maldonado Galdeano ◽  
G. Perdigón
Keyword(s):  
Immune Response ◽  
Immune System ◽  
Innate Immune Response ◽  
Lactobacillus Casei ◽  
Mononuclear Cells ◽  
Immunoglobulin A ◽  
Probiotic Bacterium ◽  
Innate Immune ◽  
Intestinal Fluids ◽  
Secretory Immunoglobulin

ABSTRACT The mechanisms by which probiotic bacteria affect the immune system are unknown yet, but many of them are attributed to an increase in the innate or in the acquired immune response. To study the influence of the probiotic bacterium Lactobacillus casei in the expression of receptors involved in the innate immune response, this bacterium was orally administered to BALB/c mice. After, they were sacrificed; the small intestine and intestinal fluids were collected to measure secretory immunoglobulin A (IgA) specific for L. casei. Mononuclear cells from Peyer's patches were isolated to determine the CD-206 and TLR-2 receptors. In histological slices we determined the number of IgA+, CD4+, CD8+, and CD3+ cells and two cytokines (interleulin-5 [IL-5] and IL-6). CD-206 and TLR-2 increased with respect to the untreated control. We did not observe an increase in the T population or in the IL-5-positive cells. IgA+ cells and IL-6-producing cells increased after 7 days of L. casei administration. We did not find specific antibodies against L. casei. The main immune cells activated after oral L. casei administration were those of the innate immune response, with an increase in the specific markers of these cells (CD-206 and TLR-2), with no modification in the number of T cells.

The C-terminal domain of Salmonid Alphavirus nonstructural protein 2 (nsP2) is essential and sufficient to block RIG-I pathway induction and interferon-mediated antiviral response.

2021 ◽  
Author(s):  
Raphaël Jami ◽  
Emilie Mérour ◽  
Julie Bernard ◽  
Annie Lamoureux ◽  
Jean K. Millet ◽  
...  
Keyword(s):  
Immune Response ◽  
Immune System ◽  
Innate Immune Response ◽  
Nuclear Localization ◽  
Innate Immune ◽  
Type I ◽  
Annual Growth Rate ◽  
Structural Protein ◽  
Terminal Domain ◽  
Nuclear Localization Sequences

Salmonid alphavirus (SAV) is an atypical alphavirus, which has a considerable impact on salmon and trout farms. Unlike other alphaviruses such as the chikungunya virus, SAV is transmitted without an arthropod vector, and does not cause cell shut-off during infection. The mechanisms by which SAV escapes the host immune system remain unknown. By studying the role of SAV proteins on the RIG-I signaling cascade, the first line of defense of the immune system during infection, we demonstrated that non-structural protein 2 (nsP2) effectively blocks the induction of type I interferon (IFN). This inhibition, independent of the protease activity carried by nsP2, occurs downstream of IRF3 which is the transcription factor allowing the activation of the IFN promoter and its expression. The inhibitory effect of nsP2 on the RIG-I pathway depends on the localization of nsP2 in the host cell nucleus which is linked to two nuclear localization sequences (NLS) located in its C-terminal part. The C-terminal domain of nsP2 by itself is sufficient and necessary to block IFN induction. Mutation of the NLS of nsP2 is deleterious to the virus. Finally, nsP2 does not interact with IRF3, indicating that its action is possible through a targeted interaction within discrete areas of chromatin, as suggested by its punctate distribution observed in the nucleus. These results therefore demonstrate a major role for nsP2 in the control by SAV of the host cell’s innate immune response. Importance The global consumption of fish continues to rise and the future demand cannot be met by capture fisheries alone due to limited stocks of wild fish. Aquaculture is currently the world’s fastest growing food production sector with an annual growth rate of 6-8 %. Recurrent outbreaks of SAV result in significant economic losses with serious environmental consequences on wild stocks. While the clinical and pathological signs of SAV infection are fairly well known, the molecular mechanisms involved are poorly described. In the present study, we focus on the non-structural protein nsP2 and characterize a specific domain containing nuclear localization sequences that are critical for the inhibition of the host innate immune response mediated by the RIG-I pathway.

2. First responders: the innate immune response

2017 ◽  
pp. 17-29
Author(s):  
Paul Klenerman
Keyword(s):  
Immune Response ◽  
Immune System ◽  
Innate Immune Response ◽  
Acute Phase Response ◽  
First Responders ◽  
Fundamental Question ◽  
Innate Immune ◽  
Rapid Action ◽  
Molecular Patterns ◽  
Damage Associated Molecular Patterns

How does the immune system know when to respond? ‘First responders: the innate immune response’ considers this fundamental question that is central to understanding both normal (e.g. to infections) and abnormal (e.g. in auto-immune diseases) responses; and designing vaccines and new therapies in cancer and infectious diseases. It looks at how ‘danger’ is sensed by the immune system through pathogen-associated molecular patterns and damage-associated molecular patterns. Having been alerted, it is important that rapid action is taken to limit the spread of a pathogen. A number of responses can be initiated immediately, forming a critical part of our innate immunity, which are followed by the acute phase response.

scholarly journals Determination of the Role and Active Sites of PKC-Delta-Like from Lamprey in Innate Immunity

2019 ◽  
Vol 20 (13) ◽  
pp. 3357
Author(s):  
Yang Xu ◽  
Huan Zhao ◽  
Yang Tian ◽  
Kaixia Ren ◽  
Nan Zheng ◽  
...  
Keyword(s):  
Immune Response ◽  
Innate Immunity ◽  
Immune System ◽  
Innate Immune Response ◽  
Active Sites ◽  
Innate Immune ◽  
Pkc Delta ◽  
Kinase C ◽  
Catalytic Fragment

Protein kinase C-δ (PKC-δ) is an important protein in the immune system of higher vertebrates. Lampreys, as the most primitive vertebrates, have a uniquevariable lymphocyte receptor (VLR) immune system. PKC-δ-like is a crucial functional gene in lampreys and is highly expressed in their immune organs. In this study, lampreys were stimulated with different immunogens, and lipopolysaccharide (LPS) was found to increase the expression of PKC-δ-like. Overexpression of PKC-δ-like could also effectively activate the innate immune response. We further demonstrated that PKC-δ-like-CF, a catalytic fragment of PKC-δ-like, is responsible for activating the innate immune response, and Thr-211, which is Thr-419 of PKC-δ-like, was confirmed to be the key site affecting PKC-δ-like-CF activity. These results indicated that PKC-δ-like from lamprey may have an important role in the innate immune response.

scholarly journals Insights into Innate Immune Response Against SARS-CoV-2 Infection

2021 ◽  
Vol 29 (3) ◽  
pp. 255-269
Author(s):  
Adina Huțanu ◽  
Anca Meda Georgescu ◽  
Akos Vince Andrejkovits ◽  
William Au ◽  
Minodora Dobreanu
Keyword(s):  
Immune Response ◽  
Immune System ◽  
Innate Immune Response ◽  
Innate Immune System ◽  
Time Course ◽  
Adaptive Immune Response ◽  
Innate Immune ◽  
Interferon Response ◽  
Humoral Factors ◽  
Key Steps

Abstract The innate immune system is mandatory for the activation of antiviral host defense and eradication of the infection. In this regard, dendritic cells, natural killer cells, macrophages, neutrophils representing the cellular component, and cytokines, interferons, complement or Toll-Like Receptors, representing the mediators of unspecific response act together for both activation of the adaptive immune response and viral clearance. Of great importance is the proper functioning of the innate immune response from the very beginning. For instance, in the early stages of viral infection, the defective interferon response leads to uncontrolled viral replication and pathogen evasion, while hypersecretion during the later stages of infection generates hyperinflammation. This cascade activation of systemic inflammation culminates with cytokine storm syndrome and hypercoagulability state, due to a close interconnection between them. Thus an unbalanced reaction, either under- or over- stimulation of the innate immune system will lead to an uncoordinated response and unfavorable disease outcomes. Since both cellular and humoral factors are involved in the time-course of the innate immune response, in this review we aimed to address their gradual involvement in the antiviral response with emphasis on key steps in SARS-CoV-2 infection.

scholarly journals Staphylococcus pseudintermedius, both commensal and pathogen

2018 ◽  
Vol 74 (1) ◽  
pp. 6042-2018
Author(s):  
Dorota Chrobak-Chmiel ◽  
Anna Golke ◽  
Kourou Dembele ◽  
Katarzyna Ćwiek ◽  
Magdalena Kizerwetter-Świda ◽  
...  
Keyword(s):  
Immune Response ◽  
Atopic Dermatitis ◽  
Immune System ◽  
Virulence Factors ◽  
Innate Immune Response ◽  
Innate Immune ◽  
Staphylococcus Pseudintermedius ◽  
Underlying Condition ◽  
Secondary Infections ◽  
Pathogenic Effects

Staphylococcus pseudintermedius is considered to be a both commensal and opportunistic canine pathogen. The anal, perineal and nasal locations appear to be the main S. pseudintermedius colonization sites, from which bacteria are transmitted to other body sites, causing secondary infections. When the immune system is compromised because of an underlying condition, the skin becomes susceptible to infection. Thus, the host’s condition seems to play a crucial role in the pathogenesis of S. pseudintermedius infections. There are some predisposing factors, one of which is atopic dermatitis. The pathogenic effects of S. pseudintermedius are mediated by several virulence factors, for instance superantigens, which play an important role by causing dermatitis. The immune system has evolved many different mechanisms to recognize and deal with pathogens, but bacteria have also developed various strategies to evade them. In this review, we focus on early stages of the innate immune response with particular emphasis on the mechanisms of recognition of staphylococci and the action of antimicrobial peptides. .

scholarly journals Fetal Lymphoid Organ Immune Responses to Transient and Persistent Infection with Bovine Viral Diarrhea Virus

Viruses ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 816 ◽  
Author(s):  
Katie J. Knapek ◽  
Hanah M. Georges ◽  
Hana Van Campen ◽  
Jeanette V. Bishop ◽  
Helle Bielefeldt-Ohmann ◽  
...  
Keyword(s):  
Immune Response ◽  
Immune System ◽  
Innate Immune Response ◽  
Adaptive Immune Response ◽  
Innate Immune ◽  
Bovine Viral Diarrhea ◽  
Diarrhea Virus ◽  
Viral Diarrhea ◽  
Adaptive Immune ◽  
Viral Diarrhea Virus

Bovine Viral Diarrhea Virus (BVDV) fetal infections occur in two forms; persistent infection (PI) or transient infection (TI), depending on what stage of gestation the fetus is infected. Examination of lymphoid organs from both PI and TI fetuses reveals drastically different fetal responses, dependent upon the developmental stage of the fetal immune system. Total RNA was extracted from the thymuses and spleens of uninfected control, PI, and TI fetuses collected on day 190 of gestation to test the hypothesis that BVDV infection impairs the innate and adaptive immune response in the fetal thymus and spleen of both infection types. Transcripts of genes representing the innate immune response and adaptive immune response genes were assayed by Reverse Transcription quatitative PCR (RT-qPCR) (2−ΔΔCq; fold change). Genes of the innate immune response, interferon (IFN) inducible genes, antigen presentation to lymphocytes, and activation of B cells were downregulated in day 190 fetal PI thymuses compared to controls. In contrast, innate immune response genes were upregulated in TI fetal thymuses compared to controls and tended to be upregulated in TI fetal spleens. Genes associated with the innate immune system were not different in PI fetal spleens; however, adaptive immune system genes were downregulated, indicating that PI fetal BVDV infection has profound inhibitory effects on the expression of genes involved in the innate and adaptive immune response. The downregulation of these genes in lymphocytes and antigen-presenting cells in the developing thymus and spleen may explain the incomplete clearance of BVDV and the persistence of the virus in PI animals while the upregulation of the TI innate immune response indicates a more mature immune system, able to clear the virus.

Plant Phenolics and Lectins as Vaccine Adjuvants

2019 ◽  
Vol 20 (15) ◽  
pp. 1236-1243 ◽  
Author(s):  
Hernández-Ramos Reyna-Margarita ◽  
Castillo-Maldonado Irais ◽  
Rivera-Guillén Mario-Alberto ◽  
Ramírez-Moreno Agustina ◽  
Serrano-Gallardo Luis-Benjamín ◽  
...  
Keyword(s):  
Immune Response ◽  
Immune System ◽  
Innate Immune Response ◽  
Adaptive Immune Response ◽  
The Body ◽  
Innate Immune ◽  
Vaccine Adjuvants ◽  
Plant Phenolics ◽  
Adaptive Immune ◽  
Foreign Substance

Background: The immune system is responsible for providing protection to the body against foreign substances. The immune system divides into two types of immune responses to study its mechanisms of protection: 1) Innate and 2) Adaptive. The innate immune response represents the first protective barrier of the organism that also works as a regulator of the adaptive immune response, if evaded the mechanisms of the innate immune response by the foreign substance the adaptive immune response takes action with the consequent antigen neutralization or elimination. The adaptive immune response objective is developing a specific humoral response that consists in the production of soluble proteins known as antibodies capable of specifically recognizing the foreign agent; such protective mechanism is induced artificially through an immunization or vaccination. Unfortunately, the immunogenicity of the antigens is an intrinsic characteristic of the same antigen dependent on several factors. Conclusion: Vaccine adjuvants are chemical substances of very varied structure that seek to improve the immunogenicity of antigens. The main four types of adjuvants under investigation are the following: 1) Oil emulsions with an antigen in solution, 2) Pattern recognition receptors activating molecules, 3) Inflammatory stimulatory molecules or activators of the inflammasome complex, and 4) Cytokines. However, this paper addresses the biological plausibility of two phytochemical compounds as vaccine adjuvants: 5) Lectins, and 6) Plant phenolics whose characteristics, mechanisms of action and disadvantages are addressed. Finally, the immunological usefulness of these molecules is discussed through immunological data to estimate effects of plant phenolics and lectins as vaccine adjuvants, and current studies that have implanted these molecules as vaccine adjuvants, demonstrating the results of this immunization.

scholarly journals Bacterial lipids: powerful modifiers of the innate immune response

F1000Research ◽  
2017 ◽  
Vol 6 ◽  
pp. 1334 ◽  
Author(s):  
Courtney E. Chandler ◽  
Robert K. Ernst
Keyword(s):  
Immune Response ◽  
Immune System ◽  
Innate Immune Response ◽  
Lipoteichoic Acid ◽  
Innate Immune ◽  
Microbial Pathogens ◽  
Host Immune System ◽  
Receptor Proteins ◽  
Bacterial Membranes ◽  
Host Innate Immune Response

The innate immune system serves as a first line of defense against microbial pathogens. The host innate immune response can be triggered by recognition of conserved non-self-microbial signature molecules by specific host receptor proteins called Toll-like receptors. For bacteria, many of these molecular triggers reside on or are embedded in the bacterial membrane, the interface exposed to the host environment. Lipids are the most abundant component of membranes, and bacteria possess a unique set of lipids that can initiate or modify the host innate immune response. Bacterial lipoproteins, peptidoglycan, and outer membrane molecules lipoteichoic acid and lipopolysaccharide are key modulators of the host immune system. This review article will highlight some of the research emerging at the crossroads of bacterial membranes and innate immunity.

scholarly journals MiR-146b Mediates Endotoxin Tolerance in Human Phagocytes

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Tiziana Ada Renzi ◽  
Marcello Rubino ◽  
Laura Gornati ◽  
Cecilia Garlanda ◽  
Massimo Locati ◽  
...  
Keyword(s):  
Immune Response ◽  
Immune System ◽  
Inflammatory Response ◽  
Innate Immune Response ◽  
Endotoxin Tolerance ◽  
Innate Immune ◽  
Human Monocytes ◽  
Key Factors ◽  
Tlr Signaling ◽  
Tolerant State

A proper regulation of the innate immune response is fundamental to keep the immune system in check and avoid a chronic status of inflammation. As they act as negative modulators of TLR signaling pathways, miRNAs have been recently involved in the control of the inflammatory response. However, their role in the context of endotoxin tolerance is just beginning to be explored. We here show that miR-146b is upregulated in human monocytes tolerized by LPS, IL-10, or TGFβpriming and demonstrate that its transcription is driven by STAT3 and RUNX3, key factors downstream of IL-10 and TGFβsignaling. Our study also found that IFNγ, known to revert LPS tolerant state, inhibits miR-146b expression. Finally, we provide evidence that miR-146b levels have a profound effect on the tolerant state, thus candidating miR-146b as a molecular mediator of endotoxin tolerance.

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