Natural killer cells in cross-regulation of IL-12 by IL-10 in Leishmania antigen-stimulated blood donor cells.

We have previously shown that natural killer (NK) cells play a role in protection against leishmaniasis. Furthermore, we have shown that NK cells in mononuclear cells derived from unexposed donors are induced to proliferate in vitro in response to leishmanial antigens. Since interleukin (IL)-12, a strong inducer of NK cells, acts on the early events in NK cells and T-cells, and is considered as an adjuvant for use in a potential antileishmaniasis antigen, we wished to investigate how this cytokine influences the in vitro Leishmania induced proliferative and cytokine response in healthy donors. We demonstrate that in an innate response to Leishmania antigen involving NK cells, a critical level of IL-12 is required to induce interferon (IFN)-gamma secretion below which, IL-10 is released in amounts which apparently inhibit IFN-gamma secretion and cellular proliferation. However, at higher IL-12 levels, there is simultaneous secretion of IFN-gamma and IL-10 as well as proliferation of cells. In a similar vein, exogenous IL-10 in turn inhibited IFN-gamma secretion as well as proliferation when used at low/medium concentrations, but at high concentrations this effect was abolished and replaced by the simultaneous detection of IFN-gamma, IL-10 and proliferation. The contribution of NK cells in cross regulation of these two very important immuneregulatory cytokines and the effect of exogenous IL-12 in a Leishmania driven response are discussed.     

Dendritic cells,but not macrophages,produce IL-12 immediately following Leishmania donovani infection

Infection with Leishmania, an obligate intracellular parasite of mononuclear phagocytes, stimulates the production of IFN-γ from NK cells, via a pathway which is dependent upon IL-12 and IL-2. IL-12 is also essential for the development of host protective T cell responses to this parasite. However, previous in vitro studies have indicated that macrophages fail to make IL-12 following infection with Leishmania, and that subsequent to infection, macrophages become refractory to normal IL-12-inducing stimuli. We have used an in situ approach to attempt to resolve this apparent paradox, and by immunostaining for IL-12 p40 protein, we now demonstrate for the first time, that dendritic cells (DC) are the critical source of early IL-12 production following Leishmania infection. IL-12 production by DC is transient, peaking at 1 day post infection and returning to the levels seen in uninfected mice by day 3. Although resident tissue macrophages fail to produce IL-12 after Leishmania infection, these cells are not totally refractory to cytokine inducing stimuli, as TNF-α production is induced by day 3 post infection. Not only do these data satisfactorily explain the dfferences between in vivo and in vitro data by identifying the cellular source of IL-12, but they also suggest a novel model for NK cell activation; namely that in response to pathogens which fail to trigger IL-12 production by macrophages, DC-T cell clusters provide the microenvironment for initial NK cell activation.     

Phagocytosis of Leishmania mexicana amastigotes by macrophages leads to a sustained suppression of IL-12 production

Healing of leishmaniases is dependent on activation of parasitized macrophages (Mϕ) by IFN-γ, which is secreted by Leishmania-specific Th1 cells. IL-12 enhances IFN-γ production by Th1 cells and is crucial for cure. The host cells of Leishmania sp., Mϕ, are a main source of IL-12 in vivo. We report that infection of quiescent murine Mϕ with L. mexicana or L. major amastigotes does not induce IL-12 production. Moreover, infection suppresses IL-12 secretion by Mϕ activated by LPS, by CD40 cross-linking or cognate interaction with Th1 cells. IL-12 secretion is also suppressed in Mϕ activated after phagocytosis of latex beads. Suppression is independent of engagement of CR3 or FcγR during phagocytosis, is not mediated by IL-10 and does not alter steady state IL-12p40 mRNA levels. In addition, suppression of IL-12 secretion does not depend on Mϕ activation concurrent to infection. In contrast, NO production was not inhibited. Thus, Mϕ effector functions are differentially affected and this may be a general effect of phagocytosis of non-activating particles. The possible implications of this effect on the infection are discussed.     

Distinct roles for IL-6 and IL-12p40 in mediating protection against Leishmania donovani and the expansion of IL-10+ CD4+ T cells

Adoptive dendritic cell (DC) immunotherapy provides a useful experimental tool to evaluate immunoregulation in vivo and has previously been successfully used to enhance host resistance in a variety of experimental models of leishmaniasis. Here, we used this approach to identify IL-6 and IL-12p40 as critical cytokines that cooperate to mediate host protection to Leishmania donovani but which act independently to regulate expansion of IL-10(+) CD4(+) T cells, shown here for the first time to be associated with this infection. Adoptive transfer of LPS-activated bone marrow-derived DC (BMDC) from wild-type mice was therapeutically beneficial and led to enhanced resistance as measured by spleen parasite burden. In contrast, IL-6- or IL-12p40-deficient BMDC had no protective benefit, indicating that production of both cytokines was essential for the therapeutic efficacy of DC. IL-10 production by CD25(-) FoxP3(-) IL-10(+) CD4(+) T cells is a strong correlate of disease progression, and BMDC from wild-type mice inhibited expansion of these cells. Strikingly, IL-12-deficient BMDC could also inhibit the expansion of this T cell population whereas IL-6-deficient BMDC could not, indicating that IL-6 played a key role in this aspect of DC function in vivo. Breadth of cytokine production is thus an important factor when considering strategies for DC-based interventions.     

IL-12和IL-18在实验性自身免疫性神经炎中的协同作用机制

目的:研究IL-12和IL-18分别在实验性自身免疫性神经炎(EAN)中的调节机制以及IL-12与IL-18的协同作用.方法:建立P0180-199特异性T细胞系.分别用IL-12或IL-18或者IL-12和IL-18进行体外干预,将不同处理组的T细胞回输到正常的大鼠体内,建立过继免疫的EAN动物模型.应用国际分级标准和临床评分对发病鼠进行临床评定;通过免疫组化检测不同组EAN鼠坐骨神经淋巴细胞浸润;ELISA法检测相关细胞因子的变化.结果:①在IL-12和IL-18共同干预的条件下,特异性T细胞TNF-α和IFN-γ的产生均增加;②与IL-12或IL-18组相比,IL-12 IL-18组大鼠临床发病明显加重,发病时间提前;③在坐骨神经标本中,与对照组相比,IL-12 IL-18组CD4 淋巴细胞浸润数量较多,而IL-12和IL-18组CD4 淋巴细胞浸润较少.结论:经IL-12和IL-18体外干预的P0180-199特异性T淋巴细胞,通过过继免疫给正常大鼠后,诱导出严重的EAN动物模型,表现出协同增强作用.     

Analysis of cytokine production by inflammatory mouse macrophages at the single-cell level: selective impairment of IL-12 induction in Leishmania -infected cells

Intracellular staining for cytokines and parasites, combined with two-color flow cytometric analyses, were used to examine the frequencies of IL-12-, TNF-α- and IL-6-producing macrophages in response to Leishmania major infection and/or activation with IFN-γ/lipopolysaccharide (LPS). Inflammatory macrophages were obtained from nonimmune granulomas, initiated by the injection of polyacrylamide microbeads (Bio-gel P-100) into subcutaneous pouches of different mouse strains. Infection of inflammatory macrophages in vitro using metacyclic promastigotes produced identical effects on cytokine responses regardless of whether cells from genetically resistant or susceptible mouse strains were used: IL-12 was not produced in response to infection itself, virtually every infected cell lost its ability to produce IL-12 in response to IFN-γ/LPS, and the IL-6 response was partially inhibited, while the TNF-α response of infected cells was unimpaired. Low-multiplicity infection of inflammatory macrophages in vivo using either metacyclic promastigotes or tissue amastigotes also resulted in the complete and selective inhibition of IL-12 responses in infected cells. These data establish the physiologic relevance of prior observations regarding the selective impairment of IL-12 induction pathways in infected macrophages, and suggest a mechanisms for the delayed onset of cell-mediated control mechanisms that is typical of even self-limiting forms of leishmanial disease.     

Ovarian follicular concentration of IL-12, IL-15, IL-18 and p40 subunit of IL-12 and IL-23

BACKGROUND: The aim of the study was to determine the presence of interleukin (IL)-12, IL-15, IL-18 and p40 subunit of IL-12/IL-23 in follicular fluid from spontaneous cycles and the relation between the concentration of selected cytokines and IVF-embryo transfer outcome. METHODS: IVF-embryo transfer and enzyme immunoassay (EIA) (R&D Systems, Minneapolis, MN, USA and MBL, Nagoya, Japan) were used. RESULTS: Follicular fluid of women included in the IVF-embryo transfer procedure contained common p40 subunit of IL-12/IL-23 (median 70.1 pg/ml), IL-15 (median 1.3 pg/ml) and IL-18 (median 38.2 pg/ml). There was a significant negative correlation between follicular fluid concentrations of IL-15 and IL-18 (R=-0.392, P=0.003). Significantly higher concentrations of common p40 subunit of IL-12/IL-23 (median 79.8 pg/ml) were found in the follicular fluid taken from follicles containing oocytes, when compared with those without an oocyte (median 44.5 pg/ml, P=0.006). Patients who achieved clinical pregnancy had significantly decreased concentration of IL-15 (median 0.8 pg/ml) compared with patients without successful IVF-embryo transfer outcome (median 1.4 pg/ml, P=0.047). CONCLUSION: Follicular fluid collected from spontaneous cycles contains detectable levels of p40 subunit of IL-12/IL-23, IL-15 and IL-18. Increased concentrations of p40 subunit of IL-12/IL-23 in follicles containing oocytes suggest an important role of this cytokine in reproduction. Possible negative value of IL-15 as a predictor of IVF-embryo transfer success remains to be determined.     

SLE患者IFN-γ、IL-4及IL-12水平变化及意义

从Th1/Th2细胞代表性细胞因子IFN γ/IL 4和IL 12水平的变化分析SLE患者Th1/Th2细胞的偏移现象。本实验通过半定量PCR法和ELISA酶联免疫检测法检测上述三种细胞因子含量。实验结果显示 ,SLE患者IL 4/IFN γ基因水平比值为0 32 8,高于对照组 (0 0 7)。ELISA检测显示IL 12在SLE患者血清中为 (38 39± 15 1)pg/ml,低于对照组 (84 97± 13 7)pg/ml(P <0 0 5 )。结论 :SLE患者Th1/Th2细胞因子平衡失调 ,IL 4细胞因子基因水平增高 ,同时血清中IL 12水平降低。     

The role of IL-12 in the maintenance of an established Th1 immune response in experimental leishmaniasis

IL-12 initiates the development of cell-mediated immunity by promoting the differentiation of naive T cells into the Th1 phenotype, and is essential in the development of a Th1 immune response to the intracellular protozoan parasite, Leishmania major. The present study investigated whether IL-12 is also required for the maintenance and effector function of an established Th1 immune response in L. major -infected mice. While neutralization of IL-12 com promised the ability of a leishmanial antigen-reactive Th1 cell clone to produce IFN-γ in vitro, lymphnode cells taken from 2-week L. major -infected mice were able to secrete IFN-γ in an IL-12-independent manner. However, when a short-term T cell line was established in vitro from lymph node cells, the production of IFN-γ again became IL-12 dependent. These results suggest that other factors may compensate for IL-12 in vivo in promoting IFN-γ production during L. major infection. To directly assess if IL-12 was required in vivo for resistance to L. major, we studied the effect of IL-12 neutralization on both a primary and secondary L. major infection in C3H mice. L. major infection in C3H mice is characterized by the development of a small lesion that heals by 8 weeks, and these animals are resistant to reinfection. As previously reported, administration of anti-IL-12 monoclonal antibody (mAb) during a primary infection led to severe disease. However, mice that had healed from a primary infection with L. major and were treated with anti-IL-12 mAb were as resistant as control animals. These findings suggest that once Th1 cells have developed, their effector function in vivo is independent of IL-12, and that this independence is not due to an intrinsic property of the T cell, but to the microenvironment created by the infection.     

脂多糖和金黄色葡萄球菌对IL-23、IL-12表达的调控

目的：检测脂多糖（LPS）和金黄色葡萄球菌（SAC）对人外周血单个核细胞（PBMC）IL-23和IL-12各亚基表达的调节作用并探索其作用机制。方法：用LPS和SAC直接刺激人PBMC，或用CD14抗体或p38丝裂原活化蛋白激酶（MAPK）抑制剂Mastoparan预处理PBMC后再予LPS和SAC刺激，半定量RT-PCR方法检测IL-23p19、IL-12p35和IL-12p40亚基的基因表达变化。结果：人PBMC组成性表达p19和p35，不表达p40。LPS和SAC可上调各亚基的表达。LPS诱导的IL-23和IL-12各亚基表达均需通过CDl4；CDl4仅部分参与SAC诱导的IL-12p40和p35表达上调，而与p19上调无关。LPS和SAC诱导的IL-23和IL-12各亚基表达均需要p38MAPK通路。结论：LPS和SAC刺激下IL-23和IL-12亚基表达及信号传导通路既有相似之处又有不同点，为单独或同时调控这两种因子的表达提供线索。     

Effects of some antigenic fractions of Leishmania major on nitric oxide production and IL-12 secretion by murine peritoneal macrophages

Nitric oxide (NO) and IL-12 are important mediators of the immune response to Leishmania major. In this study, the effects of L. major promastigotes, crude antigenic fraction (CAF) and its subfractions on NO production and IL-12 secretion by BALB/c mice peritoneal macrophages is investigated. The subfractions of CAF, namely, fractions 1, 2 and 3, that were in the molecular weight range of 97.4–66, 66–45 and below 45 kDa, respectively, were separated by SDS-PAGE. NO production was determined by using Griess reagent and IL-12 was measured by ELISA. It was found that NO production was stimulated by promastigotes but not by CAF or its subfractions. IL-12 secretion was stimulated by promastigotes, CAF and fraction 1 while fractions 2 and 3 did not have any effect.     

The power of combinatorial immunology: IL-12 and IL-12-related dimeric cytokines in infectious diseases

Appropriate induction of a Th1 immune response is required for effective antimicrobial immunity. However, dysregulated Th1 immune responses after infection may also lead to immunopathology. Thus, cell-mediated immune responses have to be tightly regulated. Upon infection, the production of interleukin (IL)-12, a heterodimeric cytokine composed of a p35 and a p40 subunit, is the dominant factor in Th1 cell development. The recent discovery of novel dimeric cytokines closely related to IL-12 add now to our understanding of cellular immunity and the fine tuning of T cell responses. At the onset of infection, IL-27, a heterodimer composed of the IL-12p40-related protein EBI-3 (Epstein-Barr virus-induced gene 3) and the IL-12p35-related protein p28 induces the expression of a functional IL-12 receptor in naive CD4⁺ T cells, making these cells sensitive to IL-12-mediated Th cell development. Later during infection, IL-23, a heterodimer composed of the IL-12p40 subunit and the IL-12p35-related molecule p19, preferentially acts on Th1 effector/memory CD4⁺ T cells. The IL-12p40 subunit can also form a homodimer, IL-12p80, which act as an IL-12 and IL-23 antagonist by competing at their receptors. This review focuses on these IL-12-related cytokines contributing to fine tuning of T cell responses after infection with intracellular pathogens.     

白介素-12及白介素-23对胃癌组织中CD4^＋记忆T细胞的影响

目的:探讨胃癌组织中IL-12、IL-23对CD4+记忆T细胞(CD4+Tm)的影响.方法:ELISA检测TNM不同期胃癌组织匀浆中IL-12、IL-23含量;不连续密度梯度离心法分离胃癌组织中的肿瘤浸润淋巴细胞(TIL),流式细胞仪检测TIL中CD4+ Tm及其亚群TEM和TCM在不同期胃癌组织中的分布状况.结果:TNM-Ⅰ、Ⅱ期胃癌组织中IL-12含量差别不明显,但均显著高于TNM-Ⅲ、TNM-Ⅳ期;TNM-Ⅰ期胃癌组织中IL-23的含量高于TNM-Ⅱ、TNM-Ⅲ、TNM-Ⅳ期.胃癌TIL中CD4+ Tm及TEM比例随TNM分期增加逐渐降低,而TCM比例逐渐升高.结论:胃癌组织中IL-12、IL-23含量的变化与胃癌TNM分期有关,且影响胃癌TIL中CD4+记忆T细胞及其亚群TCM和TEM的分布.     

Detection of asymptomatic Leishmania donovani in healthy voluntary blood donors

ObjectiveTo check incidence of Asymptomatic Leishmania donovani reporting to Armed Forces Institute of Transfusion Rawalpindi.Material and MethodsTwo thousand (n = 2000) consecutive healthy voluntary blood donors were tested for 18 s rRNA by Real time Polymerase chain reaction. One thousand (n = 1000) subject’s permanent resident of Azad Kashmir along with a thousand (n = 1000) healthy voluntary blood donors from rest of Pakistan were included. The study was carried out over a period of three months Jun – Aug 2020.ResultsTotal of 2000 blood donors were enrolled in the study, all were males with age ranging from 16 to 60 years. Stratification based on residence, 1000 (50 %) resided in the Azad kashmir, 349 (17.45 %) were from Islamabad and Rawalpindi, 541 (27.05 %) from Punjab mainly residing in Lahore and Multan, 110 (5.5 %) were from other cities of Pakistan. Grouping on the basis of age, 55.25 % ( n = 1105) of the donors were 16–25 years old, 19.45 % ( n = 389) were in age range of 26–40 years old, 15.55 % ( n = 311) were 41–50 years old and 9.75 % ( n = 195) 51–60 years old. No donor was diagnosed as an asymptomatic carrier.ConclusionScreening of blood donors for Leishmania donovani is not recommended.     

Responses to Leishmania donovani in mice deficient in interleukin-12 (IL-12), IL-12/IL-23, or IL-18

Interleukin-12 (IL-12) orchestrates acquired resistance in intracellular Leishmania donovani infection in the liver, inducing gamma interferon and, in turn, macrophage activation and parasite killing. Nevertheless, testing in IL-18(-/-) mice compared to wild-type mice and in IL-12p40(-/-) compared to IL-12p35(-/-) mice also suggested both early-acting (IL-18) and late-acting (IL-23) antileishmanial effects independent of IL-12.     

131I治疗Graves'病和HT甲亢患者治疗前后血清IL-12、IL-18的变化

目的：本文通过测定放射性碘治疗Graves’病和HT甲亢患者前后血清IL—12、IL-18的变化以期探讨^131I治疗对其自身免疫状态的影响。方法：用酶联免疫分析方法测定48例Graves’病和桥本甲亢患者^131I治疗前后血清IL—12、IL-18水平，35例健康志愿者作为对照。结果：①IL-12、IL-18在^131I治疗Graves’病和HT甲亢患者后均有显著性降低（P〈0．05）。②在治疗后各组比较中IL-12除在治愈组与缓解组无显著性差异外（P〉0．05）其余各组均有显著性差异（P〈0．05）。③IL-18在治愈组与缓解组和甲低组之间无显著性差异（P〉0．05），其余各组均有显著性差异（P〈0．05）。④TGA、TMA各组与对照组比较均有显著性差异，其余各组间无显著性差异。⑤IL-12与IL-18、TGA、TMA呈显著性相关（P〈0．05）。结论：^131I治疗Graves’病和HT甲亢不仅可以安全有效地控制甲亢症状且可促进自身免疫紊乱的改善。     

自身免疫甲状腺病患者血清中IL-12和IL-18水平的分析

目的:提供自身免疫甲状腺病(AITD)患者体内Th1/Th2平衡紊乱的依据。方法:应用酶联免疫吸附法(ELISA)测定27例Graves病(GD)、24例甲状腺功能正常的桥本甲状腺炎(HT)、25例甲状腺功能低下的HT患者及20例正常对照者血清中IL12和IL18的浓度,并检测GD患者的甲状腺刺激性抗体。结果:GD患者与甲状腺功能正常的HT患者血中IL12、IL18水平无明显差异,但均高于正常对照者的相应水平。甲状腺功能低下的HT患者血中IL12和IL18的水平与正常对照者无差异。在GD和甲功正常的HT,IL18与IL12呈明显正相关。在GD,IL12和IL18均与其甲状腺刺激性抗体(TSAb)活性呈正相关。在甲状腺功能正常的HT还存在IL12和IL18二者与甲状腺球蛋白抗体(TgAb)的显著性正相关。结论:提示Th1型细胞在GD和HT两种AITD的发病中均起重要作用。通过抑制Th2型免疫反应,促进向Th1型的转变来治疗GD时,有可能导致病情恶化。     

IL-12 is a potent neonatal vaccine adjuvant

Neonatal animals show generally poor responsiveness to foreign antigens and are known to display polarized expression of Th2-like cytokines and antibody responses. We now report that newborn mice display a reduction in peripheral expression of the Th1-inducing cytokine, IL-12. Attempts to overcome this decrease by immunization and treatment with IL-12 within 24 h of birth resulted in elevated levels of IFN-γ and IL-10 mRNA in the spleens of mice compared to animals exposed to antigen only. Moreover, such animals showed dramatic enhancement of IgG2a and IgG2b antibody levels upon adult challenge compared to mice primed with antigen alone. These effects appeared to be due to induction of neonatal B cell memory. IgG1 antibody levels, a measure of Th2 activity, were unaffected or even somewhat enhanced by neonatal IL-12 treatment. Taken together, these results provide evidence that IL-12 administration induces a Th1-like cytokine response in newborns and causes priming for heightened memory antibody responses in vivo. Our findings suggest the use of IL-12 as a vaccine adjuvant in neonates for inducing protection against common childhood pathogens.     

类风湿性关节炎患者滑膜液中IL-10、IL-12和sFasL含量的检测

为了研究细胞因子和凋亡分子在类风湿性关节炎(RA)发病中的作用,用ELISA法分析了26例RA患者滑膜液和血清中IL-12、IL-10和可溶性FasL(sFasL)的含量。结果表明RA患者滑膜液中IL-12、IL-10含量分别为(419.9±89.2)pg/ml和(187.7±34.5)pg/ml,外周血中这两种细胞因子的含量均较低,分别为(65.3±34.2)pg/ml(IL-12)和(85.0±12.7)pg/ml(IL-10)。滑膜液中sFasL的含量为266pg/ml,明显高于血清含量(36pg/ml)。这一结果提示,RA患者滑膜液中IL-12含量和sFasL增高,这些炎性细胞因子增高可能参与了关节滑膜中的自身反应性T细胞的活化,继而造成免疫损伤。