Probiotics: Shaping the gut immunological responses

Probiotics are live microorganisms exerting beneficial effects on the host’s health when administered in adequate amounts.Among the most popular and adequately studied probiotics are bacteria from the families Lactobacillaceae,Bifidobacteriaceae and yeasts.Most of them have been shown,both in vitro and in vivo studies of intestinal inflammation models,to provide favorable results by means of improving the gut microbiota composition,promoting the wound healing process and shaping the immunological responses.Chronic intestinal conditions,such as inflammatory bowel diseases(IBD),are characterized by an imbalance in microbiota composition,with decreased diversity,and by relapsing and persisting inflammation,which may lead to mucosal damage.Although the results of the clinical studies investigating the effect of probiotics on patients with IBD are still controversial,it is without doubt that these microorganisms and their metabolites,now named postbiotics,have a positive influence on both the host’s microbiota and the immune system,and ultimately alter the topical tissue microenvironment.This influence is achieved through three axes:(1)By dis-placement of potential pathogens via competitive exclusion;(2)by offering protection to the host through the secretion of various defensive mediators;and(3)by supplying the host with essential nutrients.We will analyze and discuss almost all the in vitro and in vivo studies of the past 2 years dealing with the possible favorable effects of certain probiotic genus on gut immunological responses,highlighting which species are the most beneficial against intestinal inflammation.

Effects of Rosa roxburghii&edible fungus fermentation broth on immune response and gut microbiota in immunosuppressed mice

With the rise of probiotics fermentation in food industry,fermented foods have attracted worldwide attention.In this study,protective effects of Rosa roxburghii&edible fungus fermentation broth(REFB)on immune function and gut health in Cyclophosphamide induced immunosuppressed mice were investigated.Results showed that REFB could improve the immune organ index,and promote the proliferation and differentiation of splenic T lymphocytes.In addition,it attenuated intestinal mucosal damage and improved intestinal cellular immunity.REFB administration also up-regulated the expression of IL-4,INF-γ,TNF-α,T-bet and GATA-3 mRNA in small intestine.Furthermore,administration of REFB modulated gut microbiota composition and increased the relative abundance of beneficial genus,such as Bacteroides.It also increased the production of fecal short-chain fatty acids.These indicate that REFB has the potential to improve immunity,alleviate intestinal injury and regulate gut microbiota in immunosuppressed mice.

Inflammation: Complexity and significance of cellular and molecular responses

Inflammation is a multifaceted cellular and molecular response triggered by injury,infection,or various pathological conditions.Serving as a protective defense mechanism,the inflammatory response involves clinical signs like redness,swelling,pain,and increased body temperature.Immune cells,notably neutrophils and macrophages,play key roles in orchestrating this response.The delicate balance between proinflammatory and anti-inflammatory mediators,including cytokines and chemokines,regulates the inflammatory cascade.While acute inflammation is crucial for tissue repair,chronic inflammation may indicate an imbalance,contributing to conditions like autoimmune diseases.Understanding these mechanisms is vital for developing therapeutic strategies and managing chronic diseases.

Effect of dietary supplement of inactivated Lactobacillus plantarum Ep-M 17 on growth performance,immune response,disease resistance,and intestinal microbiota in Penaeus vannamei

Our previous study found that feeding with Lactobacillus plantarum Ep-M17 could effectively affect the growth performance,immune response,and gut microbiota of Penaeus vannamei.However,high temperature and pressure during feed pelletizing is the main problem that can lead to a decrease in the activity of probiotics or cause their inactivation.Further investigation needs to investigate whether inactivated Ep-M17 can exert similar effects as live Ep-M17.Therefore,we evaluated the effects of inactivated L.plantarum Ep-M17 on growth performance,immune response,disease resistance,and gut microbiota in P.vannamei.Results show that adding inactivated Ep-M17 to the feed also promoted body weight gain and increased relative immune protection in shrimp.Also,histological examination revealed that the administration of inactivated Ep-M17 led to improvements in the density and distribution of microvilli in the intestines and enhancements in the abundance of B and R cells in the hepatopancreas.Additionally,the inactivated Ep-M17 supplementation resulted in increased activity levels of nutrient immune-related enzymes in both the shrimp hepatopancreas and intestines.Moreover,it stimulated the expression of Lvlec,PEN-3a,Crustin,LGBP,Lysozyme,and proPo genes in both the hepatopancreas and intestines.Furthermore,the inactivated Ep-M17 also increased bacterial diversity in the gut of shrimp and promoted the abundance of specific flora,facilitating the host organism’s metabolism and immunity to improve the disease resistance of shrimp.Therefore,supplementation of inactivated L.plantarum Ep-M17 in shrimp diets can exert similar effects as live L.plantarum Ep-M17 effectively improving growth performance,gut microbiota,immune response,and disease resistance in P.vannamei.

NIR-triggered on-site NO/ROS/RNS nanoreactor:Cascade-amplified photodynamic/photothermal therapy with local and systemic immune responses activation

Photothermal and photodynamic therapies(PTT/PDT)hold promise for localized tumor treatment,yet their full potential is hampered by limitations such as the hypoxic tumor microenvironment and inadequate systemic immune activation.Addressing these challenges,we present a novel near-infrared(NIR)-triggered RNS nanoreactor(PBNO-Ce6)to amplify the photodynamic and photothermal therapy efficacy against triple-negative breast cancer(TNBC).The designed PBNOCe6 combines sodium nitroprusside-doped Prussian Blue nanoparticles with Chlorin e6 to enable on-site RNS production through NIR-induced concurrent NO release and ROS generation.This not only enhances tumor cell eradication but also potentiates local and systemic antitumor immune responses,protecting mice from tumor rechallenge.Our in vivo evaluations revealed that treatment with PBNO-Ce6 leads to a remarkable 2.7-fold increase in cytotoxic T lymphocytes and a 62%decrease in regulatory T cells in comparison to the control PB-Ce6(Prussian Blue nanoparticles loaded with Chlorin e6),marking a substantial improvement over traditional PTT/PDT.As such,the PBNO-Ce6 nanoreactor represents a transformative approach for improving outcomes in TNBC and potentially other malignancies affected by similar barriers.

Immune response to inactivated bacterial vector carrying the recombinant K39 antigen of Leishmania infantum in mice

Objective:To evaluate the immunological response elicited by an inactivated bacterial vector carrying the K39 antigen of Leishmania infantum,and a purified antigen.Methods:Mice were subjected to the following treatments:(1)Purified recombinant K39(rK39)protein at a 20μg dose with complete Freund’s adjuvant;(2)Inactivated Escherichia coli(BL21 DE3)carrying the K39 protein at an equivalent total protein content of 200μg;(3)Inactivated bacteria lacking the K39 protein;(4)Non-immunized control animals.Serological monitoring was performed.All groups were challenged by intraperitoneal injection of 10^(7) Leishmania infantum promastigotes.After euthanasia,the liver and spleen were collected to analyze the levels of TNF,IFN-γ,IL-12,IL-4,and IL-10.Results:Mice immunized with purified rK39 or the inactivated bacterial vector carrying the K39 antigen of Leishmania infantum showed a long-lasting immune response with high levels of polyclonal antibodies specifically recognizing the recombinant proteins.The IgG1 subclass was the predominant immunoglobulin;however,the induction of IgG2a and the profile of cytokines produced were indicative of the induction of a mixed-type response.Conclusions:The inactivated bacterial vector carrying the K39 antigen,as well as the purified antigen can induce a long-lasting immune response in immunized mice,predominantly favouring a Th2 profile response.

Acupoint catgut-embedding therapy ameliorates DNCB-induced atopic dermatitis in BALB/c mice by regulating Th2 type immune response and reducing infiltration of CD4^(+)and CD8^(+)cells

Background:This study aimed to assess how acupoint catgut-embedding therapy influences Th2-type immune response and the infiltration of CD4^(+)and CD8^(+)cells in DNCB-induced atopic dermatitis in BALB/c mice.It also conducted an initial examination of the underlying molecular mechanisms.Methods:Seventy-two mice were randomly divided into four groups:normal control,DNCB-induced atopic dermatitis model(AD),AD with acupoint catgut-embedding treatment(ADA),and AD with sham-acupoint catgut-embedding treatment.After DNCB challenge to induce AD,the ADA group received acupoint catgut-embedding therapy treatment at Zusanli(ST 36)and Quchi(LI 11)acupoints every other week from day 8.Mice in the AD with sham-acupoint catgut-embedding treatment group underwent the same procedure as the ADA group but without catgut implantation.Severity was assessed using SCORAD on treatment days 1,10,and 20.On day 18,nine mice per group were euthanized,and the remaining on day 28.Histopathological changes were observed using hematoxylin-eosin and immunohistochemistry staining.TNF-α,IL-4,IL-6,and IL-13 levels were analyzed by ELISA,and GATA3 and STAT6 protein levels by western blot.Results:After 20 days of acupoint catgut-embedding therapy treatment,mice showed reduced dermatitis scores compared to DNCB-induced AD-like mice.Significant decreases occurred in serum IL-4,IL-6,IL-13,and TNF-αlevels.Skin analysis revealed marked reductions in CD4^(+)and CD8^(+)cell infiltration,as well as GATA3 and STAT6 protein levels.Conclusion:Acupoint catgut-embedding therapy may effectively alleviate atopic dermatitis by suppressing Th2 immune responses via the STAT6-GATA3 pathway and reducing CD4^(+)and CD8^(+)T cell infiltration in skin lesions.

Harnessing immunity:Immunomodulatory therapies in COVID-19

An overly exuberant immune response,characterized by a cytokine storm and uncontrolled inflammation,has been identified as a significant driver of severe coronavirus disease 2019(COVID-19)cases.Consequently,deciphering the intricacies of immune dysregulation in COVID-19 is imperative to identify specific targets for intervention and modulation.With these delicate dynamics in mind,immunomodulatory therapies have emerged as a promising avenue for miti-gating the challenges posed by COVID-19.Precision in manipulating immune pathways presents an opportunity to alter the host response,optimizing antiviral defenses while curbing deleterious inflammation.This review article compre-hensively analyzes immunomodulatory interventions in managing COVID-19.We explore diverse approaches to mitigating the hyperactive immune response and its impact,from corticosteroids and non-steroidal drugs to targeted biologics,including anti-viral drugs,cytokine inhibitors,JAK inhibitors,convalescent plasma,monoclonal antibodies(mAbs)to severe acute respiratory syndrome coronavirus 2,cell-based therapies(i.e.,CAR T,etc.).By summarizing the current evidence,we aim to provide a clear roadmap for clinicians and researchers navigating the complex landscape of immunomodulation in COVID-19 treatment.CS Glucocorticoids are among the most widely prescribed drugs with their immune-suppressive and anti-inflammatory effect[84].The current guidelines for the treatment of COVID-19 recommend against the use of dexamethasone or other systemic CS in non-hospitalized patients in the absence of another indication[70].The RECOVERY trial demonstrates the reduced 28-d mortality among hospitalized patients with COVID-19 using dexamethasone compared to the usual standard of care,along with other investigators,such as Ahmed and Hassan[85].The benefit of dexamethasone was seen only among participants receiving either oxygen alone or invasive mechanical ventilation at randomization but not among those receiving no respiratory support at enrollment[85].In a systematic review and meta-analysis,Albuquerque et al[86]showed that in comparison to tocilizumab,baricitinib,and sarilumab are associated with high probabilities of similar mortality reductions among hospitalized COVID-19 concurrently treated with CS.As a result of the absence of SARS-CoV-2-specific antiviral medications,the effectiveness of COVID-19 treatments is reduced.Several COVID-19 therapies are now under investigation.However,the majority of them lack specificity,efficacy,and safety[87].Immunotherapy is a ground-breaking medical treatment that manipulates the immune system to fight diseases.Translational research is rapidly progressing,recognized as a significant breakthrough in 2013[88].Among the immunotherapeutic options for treating COVID-19 are Immunoglobulin,CP,antibodies,mAbs(mAbs),NK cells,T cells,TLR,cytokine therapies and immune modulators.

Effects of Mycotoxin from Maize on Immune Response of Vaccine for Piglets

[Objective] The aim of this study was to investigate the effects of mycotoxin from moldy maize on immune response of piglets.[Method] ELISA method was used to determine the content of Aflatoxin B1 and ochratoxin A in maize; after the piglets were fed with the moldy maize,the corresponding antibody titers in the serums of piglets were measured.[Result] Antibody levels of tested group were obvious lower than that of the control,while the histological section of immune organs also suggested that mycotoxin could significantly inhibit the immune response of piglets.[Conclusion] Mycotoxin in maize had important effects on the internal organs and immune response of piglets.

Effects of Immunological Stress on Immune Response in Different Breeds of Piglets

[ Objective] The research aimed to explore effects of an immunological stress on immune response in different breeds of piglets （ Lulai pig, Laiwu pig and Yorkshire pig）. [Method] All the 12 weaning pigs （Lulai pig, Laiwu pig and Yorkshire pig） weighing （12.6 ±0.5） kg were used in a 2 x3 factorial design. The main factors consisted of immunological challenge （ LPS or saline） and breeds （ Lulai pig, Laiwu pig and Yorkshire pig）. On Day 1, six piglets of each breed were injected with LPS at the usage of 200 μg/kg BW or an equivalent amount of sterile saline, and in jected classical swine fever vaccine at the same time. Blood sample were collected on Day 2, 7 and 14 post injection to analyze the blood lympho cyte proliferation. The levels of antibodies against classical swine fever were tested on Day 1 prior to injection and on Day 7 and 14 post injection. [ Result] On Day 2 after injection, the lymphocyte transformation rate of piglets injected with LPS were significantly （P〈O. 01 ） increased compared with piglets injected with saline. The lymphocyte transformation rate of Laiwu piglets was significant higher than that of Yorkshire piglets （ P 〈 0.05）. Effects of immunological stress on the level of antibodies against classical swine fever were not significantly different among different breeds of pig lets. [ Conclusion] LPS can effectively stimulate cellular immunity response in different breeds of piglets, and the immune response ability is different among various breeds of piglets.

Induced Th2 dominant immune response in APPswe, PSEN1dE9 transgenic mice after nasal immunization with an adenoviral vector encoding 10 tandem repeats of beta-amyloid 3-10

Immunotherapy for Alzheimer＇s disease （AD） is effective in improving cognitive function in transgenic mouse models of AD. Because the AN1792 [beta-amyloid （Aβ） 1-42] vaccine was halted because of T cell mediated meningoencephalitis, many scientists are searching for a nove） vaccine to avoid the T cell mediated immune response caused by the Aβ1-42. Importantly, the time when the immunization is begun can influence the immune effect. In this study, an adenovirus vaccine was constructed containing 10 x Aβ3-10 repeats and gene adjuvant CpG DNA. Transgenic AD mice were immunized intranasally for 3 months. After 10 × Aβ3-10 vaccine immunization, high titers of anti-Aβ42 IgG1 predominant antibodies were induced. In spatial learning ability and probe tests, the 10 × Aβ3-10 immunized mice showed significantly improved memories compared to control mice. The 10 × Aβ3-10 vaccine resulted in a robust Th2 dominant humoral immune response and reduced learning deficits in AD mice. In addition, the 10 × Aβ3-10 vaccine might be more efficient if administered before Aβ aggregation at an early stage in the AD mouse brain. Thus, the adenovirus vector encoding 10 × Aβ-10 is a promising vaccine for AD.

Microglia lactylation in relation to central nervous system diseases

The development of neurodegenerative diseases is closely related to the disruption of central nervous system homeostasis.Microglia,as innate immune cells,play important roles in the maintenance of central nervous system homeostasis,injury response,and neurodegenerative diseases.Lactate has been considered a metabolic waste product,but recent studies are revealing ever more of the physiological functions of lactate.Lactylation is an important pathway in lactate function and is involved in glycolysis-related functions,macrophage polarization,neuromodulation,and angiogenesis and has also been implicated in the development of various diseases.This review provides an overview of the lactate metabolic and homeostatic regulatory processes involved in microglia lactylation,histone versus non-histone lactylation,and therapeutic approaches targeting lactate.Finally,we summarize the current research on microglia lactylation in central nervous system diseases.A deeper understanding of the metabolic regulatory mechanisms of microglia lactylation will provide more options for the treatment of central nervous system diseases.

Effects of thymol and carvacrol supplementation on intestinal integrity and immune responses of broiler chickens challenged with Clostridium perfringens

Background： Necrotic enteritis caused by Clostfidium perffingens infection leads to serious economic losses in the global poultry production. In the present study, we investigated the protective effects of essential oils （EO, which contained 25 % thymol and 25 % carvacrol as active components） supplementation on growth performance, gut lesions, intestinal morphology, and immune responses of the broiler chickens infected with C. perfringens. A total of 448 1-day-old male broiler chicks were allocated into eight treatment groups following a 4 x 2 factorial arrangement with four dietary EO dosages （0, 60, 120, or 240 mg/kg） and two infection status （with or without C. perfringens challenge from d 14 to 20）. Results： The challenge did not impair the growth performance of birds, but induced gut lesions and increased crypt depth in the ileum （P ≤ 0.05）. It also down-regulated the claudin-1 and occludin mRNA expression （P ≤0.05）, up-regulated the mRNA expression of interleukin-113 （P≤ 0.05）, tended to increase the toll-like receptor （TLR） 2 mRNA expression （P 〈 0.10） in the ileum, and enhanced the mucosal secretory IgA production （P 〈 0.05）. In the challenged birds, dietary EO supplementation linearly alleviated the gut lesions and improved the ratio of villus height to crypt depth （P ≤0.05）, and the supplementation of 120 and 240 mg/kg EO increased the serum antibody titers against Newcastle disease virus （P≤ 0.05）. Regardless of challenge, the EO supplementation showed a tendency to linearly elevate the feed conversion efficiency between 14 and 28 d of age as well as the occludin mRNA expression （P〈 0.10）, and linearly inhibited the mRNA expression of TLR2 and tumor necrotic factor-o in the ileum （P≤ 0.05）. Conclusions： The dietary supplementation of EO could alleviate the intestinal injury by improving intestinal integrity and modulating immune responses in the C. perffingens-challenged broiler chickens.

Effects of dietary supplementation of probiotic,Clostridium butyricum,on growth performance,immune response,intestinal barrier function,and digestive enzyme activity in broiler chickens challenged with Escherichia coli K88

Background： Colibacillosis caused by enterotoxigenic Escherichia coil （E. coil} results in economic losses in the poultry industry. Antibiotics are usually used to control colibacillosis, however, E. coli has varying degrees of resistance to different antibiotics. Therefore the use of probiotics is becoming accepted as an alternative to antibiotics. In this study, we evaluated the effects of Clostfidium butyricum （C. butyficum） on growth performance, immune response, intestinal barrier function, and digestive enzyme activity in broiler chickens challenged with Eschefichia coli （E. coil） K88. Methods： The chickens were randomly divided into four treatment groups for 28 days. Negative control treatment （NC） consisted of birds fed a basal diet without E. coil K88 challenge and positive control treatment （PC） consisted of birds fed a basal diet and challenged with E. coil K88. C. buO/ricum probiotic treatment （CB） consisted of birds fed a diet containing 2 x 107 cfu C. buO/ricum/kg of diet and challenged with E. coil K88. Colistin sulfate antibiotic treatment （CS） consisted of birds fed a diet containing 20 mg colistin sulfate/kg of diet and challenged with E. coil K88. Results： The body weight （BW） and average day gain （ADG） in the broilers of CB group were higher （P 〈 0.05） than the broilers in the PC group overall except the ADG in the 14-21 d post-challenge. The birds in CB treatment had higher （P 〈 0.05） concentration of tumor necrosis factor-a （TNF-a） at 3 and 7 d post-challenge, and higher （P 〈 0.05） concentration of interleukin-4 （IL-4） at 14 d post-challenge than those in the PC treatment group. The concentration of serum endotoxin in CB birds was lower （P 〈 0.05） at 21 d post-challenge, and the concentrations of serum diamine oxidase in CB birds were lower （P 〈 0.05） at 14 and 21 d post-challenge than in PC birds. Birds in CB treatment group had higher （P 〈 0.05） jejunum villi height than those in PC, NC, or CS treatment at 7, 14, and 21 d post-challenge. In comparison to PC birds, the CB birds had lower （P 〈 0.05） jejunum crypt depth during the whole experiment. The birds in CB or CS treatment group had higher （P 〈 0.05） activities of amylase and protease at 3, 7, and 14 d post-challenge, and higher （P 〈 0.05） activity of lipase at 3, 7 d post-challenge than PC birds.

Immune response,stress resistance and bacterial challenge in juvenile rainbow trouts Oncorhynchus mykiss fed diets containing chitosan-oligosaccharides

Effects of dietary supplementation of chitosan-oligosaccharides （COS） on the growth performance, immune response, stress resistance, and disease resistance of juvenile rainbow trout Oncorhynchus mykiss were studied. Four experimental diets containing 0, 20, 40, or 60 mg/kg COS （COSO, COS20, COS40, and COS60, respectively） were fed to juvenile rainbow trout （initial weight = 5.2 ± 0.3 g） for 8 weeks. By the end of the feeding trial, representative groups of fish from each dietary treatment were challenged with stressor （30 see air exposure） and pathogen exposure （intraperitoneal injection with Aeromonas hydrophila ）. Results showed that supplementation of COS in diets did not affect production performance and body composition of rainbow trout. However, fish fed the COS40 diet demonstrated improved phagocytic activities, respiratory burst activities and decreased serum cortisol level. Additionally, survival following A. hydrophila challenge was significant higher among fish fed the COS-supplemented feeds, although there was no difference based on the level of supplementation. The present study suggests that COS can be used as an immuno-stimulant in rainbow trout feeds

Helicobacter pylori infection: Host immune response, implications on gene expression and microRNAs

Helicobacter pylori(H. pylori) infection is the most common bacterial infection worldwide. Persistent infection of the gastric mucosa leads to inflammatory processes and may remain silent for decades or progress causing more severe diseases, such as gastric adenocarcinoma. The clinical consequences of H. pylori infection are determined by multiple factors, including host genetic predisposition, gene regulation, environmental factors and heterogeneity of H. pylori virulence factors. After decades of studies of this successful relationship between pathogen and human host, various mechanisms have been elucidated. In this review, we have made an introduction on H. pylori infection and its virulence factors, and focused mainly on modulation of host immune response triggered by bacteria, changes in the pattern of gene expression in H. pylori-infected gastric mucosa, with activation of gene transcription involved in defense mechanisms, inflammatory and immunological response, cell proliferation and apoptosis. We also highlighted the role of bacteria eradication on gene expression levels. In addition, we addressed the recent involvement of different microRNAs in precancerous lesions, gastric cancer, and inflammatory processes induced by bacteria. New discoveries in this field may allow a better understanding of the role of major factors involved in the pathogenic mechanisms of H. pylori.

Effects of dietary supplementation with Clostridium butyricum on the growth performance and humoral immune response in Miichthys miiuy

The effects of dietary supplementation with Clostridium butyricum on growth performance and humoral immune response in Miichthys miiuy were evaluated. One hundred and fifty Miichthys miiuy weighing approximately 200-260 g were divided into five groups and reared in 15 tanks with closed circuiting culture system. The animals were fed 5 diets： basal diet only （control） or supplemented of the basal diet with C. butyricum at doses of 10^3 （CB1）, 10^5 （CB2）, 10^7 （CB3） or 10^9 （CB4） CFU/g. Compared with the control, the serum phenoloxidase activity was significantly increased by the supplementation （P〈0.05）, acid phosphatases activity was increased significantly （P〈0.05） at the doses of 10^9 CFU/g. Serum lysozyme activity peaked at dose of 10^7 CFU/g and in the skin mucus at dose of 10^9 CFU/g. Immunoglobulin M level in the serum and skin mucus was increased except at dose of 10^3 CFU/g （P〈0.05）. The growth at the dose of 10^9 CFU/g was higher than that of the control （P〈0.05）. It is concluded that supplementation of C. butyricum can mediate the humoral immune responses and improve the growth performance in Miichthys miiuy.

Th immune response induced by H pylori vaccine with chitosan as adjuvant and its relation to immune protection

AIM： To study the immunological protective effect of H pylori vaccine with chitosan as an adjuvant and its mechanism. METHODS： Female BALB/c mice were randomly divided into seven groups and orally immunized respectively with PBS, chitosan solution, chitosan particles, H pylori antigen, H pylori antigen plus cholera toxin （CT）, H pylori antigen plus chitosan solution, Hpylori antigen plus chitosan particles once a week for four weeks. Four weeks after the last immunization, the mice were challenged twice by alive Hpylori （1 × 10^9 CFU/mL） and sacrificed. Part of the gastric mucosa was embedded in paraffin, cut into sections and assayed with Giemsa staining. Part of the gastric mucosa was used to quantitatively culture Hpylori. EUSA was used to detect cytokine level in gastric mucosa and anti- Hpylori IgG1, IgG2a levels in serum. RESULTS： In the groups with chitosan as an adjuvant, immunological protection was achieved in 60% mice, which was significantly higher than in groups with H pylori antigen alone and without H pylori antigen （P 〈 0.05 or 0.001）. Before challenge, the level of IFN and IL-12 in gastric mucosa was significantly higher in the groups with chitosan as an adjuvant than in the control group and the group without adjuvant （P 〈 0.05 or 0.005）. After challenge, the level of IFN and IL-12 was significantly higher in the groups with adjuvant than in the groups without adjuvant and antigen （P 〈 0.05 or 0.001）. Before challenge, the level of IL-2 in gastric mucosa was not different among different groups. After challenge the level of IL-2 was significantly higher in the groups with adjuvant than in the control group （P 〈 0.05 or 0.001）. Before challenge, the level of IL-10 in gastric mucosa was significantly higher in the groups with chitosan as an adjuvant than in other groups without adjuvant （P 〈 0.05 or 0.01）. After challenge, the level of IL-10 was not different among different groups. Before challenge, the level of IL-4 in gastric mucosa was significantly higher in the groups with chitosan as an adjuvant than in other groups without adjuvant （P 〈 0.05）. After challenge, the level of IL-4 was significantly higher in the groups with chitosan particles as an adjuvant than in the group with CT as an adjuvant （P 〈 0.05）, and in the group with chitosan solution as an adjuvant, the level of IL-4 was significantly higher than that in control group, non-adjuvant group and the groups with CT （P 〈 0.05 or 0.001）. The ratio of anti- Hpylori IgG2a/ IgG1 in serum was significantly lower in the groups with chitosan as an adjuvant than in the groups with CT as an adjuvant or without adjuvant （P 〈 0.01）. CONCLUSION： H pylori vaccine with chitosan as an adjuvant can protect against H pylori infection and induce both Thl and Th2 type immune response.

CagA+ H pylori infection is associated with polarization of T helper cell immune responses in gastric carcinogenesis

AIM:To characterize the immune responses including local and systemic immunity induced by infection with H pylori,especially with CagA+ H pylori strains and the underlying immunopathogenesis. METHODS:A total of 711 patients with different gastric lesions were recruited to determine the presence of H pylori infection and cytotoxin associated protein A (CagA),the presence of T helper (Th) cells and regulatory T (Treg) cells in peripheral blood mononuclear cells (PBMCs),expression of plasma cytokines,and RNA and protein expression of IFN-γ and IL-4 in gastric biopsies and PBMCs were determined by rapid urease test,urea 14C breath test,immunoblotting test,flow cytometry ,real time RT-PCR and immunohistochemistry. RESULTS:Of the patients,629 (88.47%) were infected with H pylori ; 506 (71.16%) with CagA+ and 123 (17.30%) with CagA- strains. Among patients infected with CagA+ H pylori strains,Th1-mediated cellular immunity was associated with earlier stages of gastric carcinogenesis,while Th2-mediated humoral immunity dominated the advanced stages and was negatively associated with an abundance of Treg cells. However,there was no such tendency in Th1/Th2 polarization in patients infected with CagA- H pylori strains and those without H pylori infection. CONCLUSION:Polarization of Th cell immune responses occurs in patients with CagA+ H pyloriinfection,which is associated with the stage and severity of gastric pathology during the progression of gastric carcinogenesis. This finding provides further evidence for a causal role of CagA+ H pylori infection in the immunopathogenesis of gastric cancer.

Helicobacter pylori vac A genotype is a predominant determinant of immune response to Helicobacter pylori CagA

To evaluate the frequency of Helicobacter pylori (H. pylori) CagA antibodies in H. pylori infected subjects and to identify potential histopathological and bacterial factors related to H. pylori CagA-immune response. METHODSSystematic data to H. pylori isolates, blood samples, gastric biopsies for histological and molecular analyses were available from 99 prospectively recruited subjects. Serological profile (anti-H. pylori, anti-CagA) was correlated with H. pylori isolates (cagA, EPIYA, vacA s/m genotype), histology (Sydney classification) and mucosal interleukin-8 (IL-8) mRNA and protein expression. Selected H. pylori strains were assessed for H. pylori CagA protein expression and IL-8 induction in co-cultivation model with AGS cells. RESULTSThirty point three percent of microbiologically confirmed H. pylori infected patients were seropositive for CagA. Majority of H. pylori isolates were cagA gene positive (93.9%) with following vacA polymorphisms: 42.4% vacA s1m1, 23.2% s1m2 and 34.3% s2m2. Anti-CagA-IgG seropositivity was strongly associated with atrophic gastritis, increased mucosal inflammation according to the Sydney score, IL-8 and cagA mRNA expression. VacA s and m polymorphisms were the major determinants for positive (vacA s1m1) or negative (vacA s2m2) anti-CagA serological immune response, which also correlated with the in vitro inflammatory potential in AGS cells. In vitro co-cultivation of representative H. pylori strains with AGS cells confirmed functional CagA translocation, which showed only partial correlation with CagA seropositivity in patients, supporting vacA as major co-determinant of the immune response. CONCLUSIONSerological immune response to H. pylori cagA+ strain in H. pylori infected patients is strongly associated with vacA polymorphism, suggesting the crucial role of bacterial factors in immune and clinical phenotype of the infection.