淋巴细胞亚群功能状态的影响

目的：探讨黄芪注射液对银屑病患者辅助性T淋巴细胞（Th细胞）亚群功能状态的影响。方法：对20例银屑病患者的外周血淋巴细胞体外分别经植物血凝素（PHA）和PHA＋黄芪诱导：即病例对照组和病例黄芪组,同时对10例健康志愿者外周血淋巴细胞体外经PHA诱导（即正常对照组）,各组培养48h,用ELISA法检测培养上清液中Th类细胞因子IFN-γ和IL-4含量。结果：病例对照组IFN-γ水平高于正常对照组（P〈0.05）,而IL-4水平低于正常对照组（P〈0．05）。病例黄芪组IFN-γ水平低于病例对照组（P〈0．05）,而IL-4水平高于病例对照组（P〈0．05）。结论：黄芪注射液可显著下调银屑病患者Th1亚群优势状态。促进向Th2亚群转换,改善患者Th1／Th2失衡状态,对银屑病的治疗具有重要意义。     

结核性胸液淋巴细胞极化相关机制研究

目的　探讨结核性胸膜炎发病的免疫学机制。方法　结核性渗出性胸膜炎患者19例,在抗结核治疗前首次所取胸液分离的淋巴细胞为胸液组;健康献血员19名外周静脉血分离的淋巴细胞为正常组;正常组淋巴细胞加入卡介苗提取物(斯奇)孵育为实验组。采用ELISA法测定上述各组淋巴细胞培养 48 h后上清液中γ干扰素(IFN- γ)、白介素 4(IL -4)的水平。结果　结核性胸膜炎患者胸液淋巴细胞培养上清液中IFN -γ水平较正常组明显升高(P<0.01),而IL- 4水平则较正常组有所下降(P<0.05)。正常人外周血淋巴细胞经斯奇康孵育的培养上清中 IFN -γ、IL- 4 水平与胸液组基本一致(P>0.05)。结论结核性胸液淋巴细胞主要以分泌 IFN -γ为主的Th1细胞占多数,表现为 Th1优势;而分泌 IL- 4 为主的 Th2细胞则处于相对弱势。这种极化现象是由与斯奇康具有相似抗原特性的结核分支杆菌菌体抗原来介导的。     

结核病合并慢性乙肝患者TNF—α、IFN-γ、IL-12变化及意义

【目的】研究结核病合并慢性乙肝患者血清肿瘤坏死因子-α（TNF-α）、γ干扰素（IFN-γ）及白细胞介素-12（IL-12）水平的变化及意义。【方法】肺结核并HBsAg阳性患者21例（A组）,单纯肺结核患者30例（B组）,健康对照组30例（C组）。应用酶联免疫吸附法（ELISA）测定三组血清中TNF-α、IFN-γ、IL-12浓度水平。【结果】A组和B组TNF-α水平均高于C组（P〈0．01）;但A组T组和B组之间TNF-α水平差异无显著性（P〉0．05）;B组IFN-γ、IL-12水平均低于C组（P〈0．05）;而A组IFN-γ、IL-12水平均低于B组（P〈0．05）。【结论】在结核病合并慢性乙肝患者的体内,可能存在着显著的Th1细胞免疫应答减弱。     

健康人外周血白念珠菌烯醇化酶抗原特异性T细胞检测

目的研究白念珠菌免疫优势抗原烯醇化酶(Enolase,Eno)的细胞免疫应答类型。方法以白念珠菌重组抗原Eno为刺激物,细胞刺激剂PHA为阳性对照,用酶联免疫斑点技术(enzyme linked immunospot assay,ELISPOT)检测25例健康人外周血单个核细胞(peripheral blood mononuclear cell,PBMC)分泌干扰素γ(interferonγ,IFN-γ)、白细胞介素-4(interleukin-4,IL-4)和白细胞介素-17A(interleukin-17,IL-17A)的阳性斑点形成细胞(spot forming cell,SFC)频数。结果Eno刺激后,25例健康人分泌IFN-γ,IL-4和IL-17A的Eno抗原特异性T淋巴细胞频数分别为14.00(8.50,39.00)、0(0,0)和2(1,4.50)个,三者间差异具有统计学意义(均P0.05)。IFN-γ,IL-4和IL-17A的应答率分别为100%(25/25),4.00%(1/25)和88.00%(22/25),三者之间差异具有统计学意义(均P0.05)。Eno刺激后的强IFN-γ(SFC≥20)应答率为40.00%(10/25),无受试者产生强IL-17A和强IL-4应答。受试者对Eno的应答模式以同时产生Th1和Th17型应答为主,占84.00%(21/25);3例研究对象仅产生Th1型细胞免疫应答(12.00%,3/25),4%(1/25)受试者同时产生Th1,Th2和Th17型三种细胞免疫应答,未观察到仅产生Th2型或Th17型细胞免疫应答者。结论白念珠菌免疫优势抗原Eno诱导的T细胞免疫以Th1型和Th17型为主,提示该抗原将产生保护性细胞免疫应答,具有成为理想疫苗的潜能。     

细胞因子对小鼠结核分枝杆菌感染的免疫保护作用

目的 研究细胞因子IFN-γ和TNF对小鼠结核分枝杆菌感染的免疫保护作用.方法 小鼠结核分枝杆菌感染后第5 d给予IFN-γ和/或TNF治疗,观察治疗后半数死亡时间、一定时间内的死亡率、脾内活菌数,检测脾细胞分泌IFN-γ和IL-4水平(ELLSA法)及MΦ产生NO水平(用Griess试剂).结果 IFN-γ和TNF联用组与单纯攻毒组比较明显延长感染小鼠丰数死亡时间、降低感染小鼠35 d内的死亡率、显著减少感染小鼠脾内活菌数,脾细胞IFN-γ分泌水平明显升高,IL-4分泌水平显著降低,MO产生NO水平明显增加.结论 IFN-γ和TNF联合诱导MΦ产生NO,促进Th1细胞反应,抑制Th2细胞反应,改变了Th1/Th2平衡,对小鼠结核分枝杆菌感染产生保护效应.     

类风湿关节炎血清和滑液Th1／Th2细胞因子的水平及意义

目的初步探讨类风湿关节炎患者免疫功能紊乱的机制.方法采用酶联免疫吸附法(ELISA)检测类风湿关节炎患者血清和关节滑膜液中Th1细胞分泌的细胞因子IL-2、IFN-γ和Th2细胞分泌的细胞因子IL-6、IL-10的水平.结果类风湿关节炎患者血清及滑膜液中IL-2、IFN-γ的水平与正常对照组相比明显升高,差异具有显著性(p＜0.01或p＜0.05),而IL-6、IL-10的水平降低,差异具有显著性(p＜0.01或p＜0.05).结论在类风湿关节炎患者血清及滑膜液中Th1/Th2细胞分泌的细胞因子水平存在着明显失衡,两者以Th1细胞分泌细胞因子占优势,这可能与其发病机制密切相关.     

流式微珠阵列法检测IFN-γ诱导的Jurkat细胞Th1/Th2细胞因子表达

本研究旨在探讨流式微珠阵列法检测Th1／Th2细胞因子表达及IFN-1应用于T淋巴细胞白血病治疗的临床价值。以不同浓度IFN-γ诱导培养Jurkat细胞48小时，用流式微珠阵列法检测培养上清液中IL-2、IL-6、TNF-α和IFN-γ表达，并采用流式细胞术检测膜上IL-2受体（CD25）的表达。结果表明：IFN-γ诱导Jurkat细胞IL-2和TNF-α的表达呈浓度依赖性升高，未检测到IL-6表达，CD25表达明显升高。结论：Jurkat细胞能被IFN-γ诱导高表达Th1细胞因子和CD25，流式微珠阵列法能准确客观地反映Th1／Th2细胞因子表达的动态变化。     

抗结核药物性肝炎患者血清IL-10与IFN—γ水平的变化及意义

目的探讨抗结核药物性肝炎患者血清白细胞介素-10（IL-10）、干扰素-γ（IFN-γ）水平的变化及其临床意义。方法采用双抗体夹心ELLSA法检测60例抗结核治疗2个月后出现药物性肝炎的继发性肺结核患者（药物性肝炎组）血清IL-10、IFN-γ水平。选择20例抗结核治疗2个月后未出现肝损害的继发性肺结核患者作对照。结果药物性肝炎组血清IL-10水平显著低于对照组,而血清IFN-γ水平显著高于对照组（均P〈0．01）;ALT200～400U·L^-1组、ALTM00U·L^-1组血清IL—10水平与ALT〈200U·L^-1组比较差异均无统计学意义（均P〉0．05）,ALT200—400U·L^-1组、ALT〉400U·L^-1组血清IFN-γ水平均明显高于ALT〈200U·L^-1组（P〈0．05或P〈0．01）,相关性分析结果显示,出现肝功能损害时服用抗结核药的时间与血清IL-10、IFN-γ水平均无相关性（r=-0．45、0．03,均P〉0．05）。结论1）抗结核药物性肝炎的出现可能与细胞免疫功能出现紊乱有关。2）患者出现肝功能损害时服用抗结核药的时间长短与血清IL-10、IFN-γ水平无相关性。3）检测血清IL-10、IFN-γ水平有助于了解肝细胞损伤程度。     

乳腺良恶性肿瘤患者血清Th1／Th2细胞因子中IL-2特点

目的 分析乳腺良、恶性肿瘤患者血清Th1／Th2细胞因子中IL-2的特点及其意义。方法 用流式荧光免疫微球分析技术（Flow Fluorenscence Immunmicrobeads Amay，FFIA）检测乳腺良、恶性肿瘤患者血清Th1／Th2细胞因子水平。Th1型细胞因子包括IL-2、TNF-α、IFN-γ，Th2型细胞因子包括IL-4、IL-5、IL-10。结果 乳腺良、恶性肿瘤患者血清IL-2水平在检测线以下（IL-2=0）的分别为34．1％（15／44）和42．8％（20／47），明显不同于其他细胞因子。在乳腺良、恶性肿瘤患者中，血清IL-2=0组，IFN-γ、IL-4、IL-5、IL-10水平均相应较低，与血清IL-2〉0组比较差异有统计学意义（P〈0．01），其中TNF-α水平差异无统计学意义（P〉0．05）。乳腺恶性肿瘤中，IL-2水平与肿瘤大小及淋巴结转移状态无相关性。结论 乳腺良、恶性肿瘤患者血清IL-2水平可能影响IFN-γ、IL-4、IL-5、IL-10表达，在乳腺恶性肿瘤中IL-2水平状态与肿瘤大小及淋巴结转移状态无相关性。     

NOD1mRNA调节Th1/Th2和Treg/Th17细胞因子在肺结核中的免疫机制及预后价值研究

目的 探究肺结核(tuberculosis,TB)患者核苷酸结合寡聚化结构域1(nucleotide binding oligomerization domain1,NOD1）表达水平与辅助性T细胞1(Th1)/辅助性T细胞2(Th2),辅助性T细胞17(Th17)/调节性T细胞(regulatory T cell,Treg)平衡的相关性,分析NOD1 mRNA是否通过调节Th1/Th2,Treg/Th17的平衡参与肺结核细胞免疫进展过程。方法 运用病例对照研究,收集2021年6月～2022年7月昌吉市人民医院结核病门诊收治的肺结核患者50例作为肺结核组,同期健康体检者50例作为对照组。所有病例均标准抗结核治疗6个月,利用实时荧光定量聚合酶链式反应(q PCR)法检测患者抗结核治疗前后外周血单个核细胞NOD1基因的表达,酶联免疫吸附试验（ELISA）法检测血清Th1/Th2和Th17/Treg的细胞因子γ-干扰素（interferon-γ,IFN-γ）、白细胞介素-4(IL-4)、白细胞介素-10(IL-10)和白细胞介素-17(IL-17)的表达水平。将抗结核治疗前后NOD1与细胞因...     

IL-10-producing T cells suppress immune responses in anergic tuberculosis patients

The lethality of Mycobacterium tuberculosis remains the highest among infectious organisms and is linked to inadequate immune response of the host. Containment and cure of tuberculosis requires an effective cell-mediated immune response, and the absence, during active tuberculosis infection, of delayed-type hypersensitivity (DTH) responses to mycobacterial antigens, defined as anergy, is associated with poor clinical outcome. To investigate the biochemical events associated with this anergy, we screened 206 patients with pulmonary tuberculosis and identified anergic patients by their lack of dermal reactivity to tuberculin purified protein derivative (PPD). In vitro stimulation of T cells with PPD induced production of IL-10, IFN-gamma, and proliferation in PPD(+) patients, whereas cells from anergic patients produced IL-10 but not IFN-gamma and failed to proliferate in response to this treatment. Moreover, in anergic patients IL-10-producing T cells were constitutively present, and T-cell receptor-mediated (TCR-mediated) stimulation resulted in defective phosphorylation of TCRzeta and defective activation of ZAP-70 and MAPK. These results show that T-cell anergy can be induced by antigen in vivo in the intact human host and provide new insights into mechanisms by which M. tuberculosis escapes immune surveillance.     

Evaluation of memory immune response to mycobacterium extract among household contact of tuberculosis cases

The human immune response to tuberculosis (TB) is especially mediated by T CD4⁺lymphocytes. However, more studies are needed in order to understand the exact role of each cytokine in the mechanisms for cures. In this article, our aim was to analyze the production of TNF‐α, IL‐10, and IFN‐γ in peripheral blood mononuclear cells (PBMCs) among the household contacts of common primary TB cases, with or without histories of active TB infection, who were negative to parasitological and HIV tests. In order to characterize the cytokine production, PBMCs from these groups werestimulated with whole‐protein extract of M. tuberculosis (WPE) antigen (rAgTb) for 24 and 48 hr. The culture supernatants were collected and IFN‐γ, TNF‐α, and IL‐10 were assayed using capture ELISA. There were no statistical differences between primary TB cases and their household contacts with or without previous histories of lung TB. Our results suggest that T memory cells, T regulatory cells, and the Th1/Th2 dichotomy may be responsible for the results described in this article. Further studies are currently underway. J. Clin. Lab. Anal. 23:57–62, 2009. © 2009 Wiley‐Liss, Inc.     

Cellular immune response from Chagasic patients to CRA or FRA recombinant antigens of Trypanosoma cruzi

We propose to analyze the relation between the cellular immune response of Chagas' disease patients after in vitro stimulation of peripheral blood mononuclear cells (PBMC) with recombinant antigens cytoplasmatic repetitive antigen (CRA) or flagellar repetitive antigen (FRA) of T. cruzi and the chronic clinical forms of disease. Cells were stimulated using phytohemagglutinin, CRA, FRA, or a soluble antigen of Epimastigota (Ag-Epi) for 24 hr, 72 hr, or 6 days. The proliferation of cells was evaluated after 6 days of culture by quantification of incorporated 3H-thymidine. Cytokines were measured in the supernatants obtained after 24 hr (tumor necrosis factor [TNF]-alpha and interleukin [IL]-4), 72 hr (IL-10), and 6 days (interferon [IFN]-gamma) using enzyme-linked immunosorbent assay (ELISA). Cells of the Chagas patients stimulated with the recombinant antigens exhibited higher proliferation responses compared with that of non-Chagas (NC) individuals. However, when proliferation was compared between patients with the cardiac form (CF) or indeterminate form (IF), it was not possible to establish a difference in the response. So far as the cytokines secreted in the culture supernatants after stimulation in vitro with T. cruzi antigens were concerned, the results showed that CRA, as well as Epi-Ag, were able to stimulate the production of TNF-alpha and IFN-gamma in Chagas patients as compared with NC individuals. However, the cytokine levels after stimulation with the T. cruzi antigens were not different between the patients with CF and IF. CRA was capable of inducing a T helper type 1 (Th1) immune response, with elevated production of TNF-alpha and IFN-gamma in Chagas patients that are carriers of CF and IF clinical forms.     

Changes in immune responses to antigen applied to tape-stripped skin with CpG-oligodeoxynucleotide in mice.

CpG-oligodeoxynucleotide (CpG-ODN) plays a critical role in immunity via the augmentation of Th1 and suppression of Th2 responses. We examined here the effect of CpG-ODN on the immune response to an antigen applied to tape-stripped mouse skin by evaluating the production of cytokines and Ig isotypes. Confocal laser scanning microscopy revealed that the model antigen, OVA, and CpG-ODN easily penetrated the tape-stripped skin. Co-administration of CpG-ODN and OVA to the disrupted skin elicited an antigen-specific Th1-predominant immune response and enhanced the production of Th1-type cytokines, IL-12 and IFN-gamma. On the other hand, the production of a Th2-type cytokine, IL-4, was drastically suppressed. Cytokine production was supported by the expression of mRNA in the draining lymph node. In terms of antigen-specific antibody production, the level of IgG2a which is regulated by IFN-gamma was increased by CpG-ODN, but IgE production regulated by IL-4 was suppressed. Furthermore, administration of CpG-ODN via the skin drastically attenuated the production of IgE in mice undergoing IgE-type immune response. Administration of CpG-ODN through the skin may shift the immune response from Th2 to Th1-like response. These results suggested that administration of CpG-ODN via skin is a simple strategy for patients with diseases like AD, which is characterized by Th2-dominated inflammation.     

A novel immunogen to modulate cytokine production and promote immune system reconstitution in HIV-AIDS

This 'proof of concept' study was implemented in anticipation of identifying and testing a novel antigen of human origin as a potential immunogen in a paradigm that emphasizes immunomodulation and immune system reconstitution as requisites to the development of an effective human immunodeficiency virus (HIV)-acquired immune deficiency syndrome vaccine. Fifteen HIV-infected, highly active antiretroviral therapy (HAART) naive, otherwise healthy male seropositive patients were stratified by [CD4+] into 3 groups of 5 patients: group 1 >500/mm; group 2 > 250/mm but <500/mm; and group 3 < 250/mm. Five healthy male subjects were used as controls. Replicate peripheral blood mononuclear cell (PBMC) [H]thymidine uptake phytohemaglutinin-stimulated proliferation studies, and serum cytokine assays were carried out in the presence or absence of Kveim antigen at dilutions ranging from 0.001 to 100 μg/mL. Serum cytokines [interleukin-2 (IL-2), IL-4, IL-6, interferon gamma, and tumor necrosis factor alpha] were assayed using standardized methodology. Nonparametric statistical analyses and linear regression analysis were used to test for statistical significance and strength of associations. PBMCs harvested from HIV-infected patients and incubated, ex vivo, demonstrated reproducible, antigen concentration-dependent changes in cytokine production over a range of antigen concentrations (0.001-100 μg/mL) in contrast to antigen-naive PBMCs and controls. Significant correlations were demonstrated between antigen concentration and the amount of cytokines secreted. The magnitude of the cytokine response and the patterns of cytokine secretion were HIV group-specific and could be used to identify and distinguish between the 3 groups of HIV-infected subjects. A shift toward the production of type 1-like (Th1) cytokines characteristically seen in systemic sarcoidosis and associated with effective HAART was seen when patterns of cytokine secretion were compared between antigen exposed and antigen-naive PBMCs. PBMCs harvested from seropositive HIV-infected patients and exposed to the Kveim antigen have the following properties: (1) They demonstrate proliferation and exhibit an antigen concentration-dependent secretion of cytokines. The magnitude of the cytokine response can be used to identify and distinguish between groups of seropositive patients stratified by [CD4+]. (2) These PBMCs secrete cytokines in patterns suggestive of a shift to a type 1-like (Th1) response characteristic of HAART and sarcoidosis as opposed to the type 2-like (Th2) cytokine profile characteristic of HIV-acquired immune deficiency syndrome.     

Isolation of mycobacterium-reactive CD1-restricted T cells from patients with human immunodeficiency virus infection.

Because CD1-restricted T cells lack CD4 but produce IFN-gamma in response to nonpeptide mycobacterial antigens, they could play a unique role in immunity to tuberculosis. We studied CD1-restricted T cells in the context of HIV infection by expanding CD4(-) T cell lines from 10 HIV-infected patients. Upon stimulation with Mycobacterium tuberculosis antigen or upon exposure to macrophages infected with M. tuberculosis, these T cell lines proliferated, produced IFN-gamma, and showed cytolytic T cell (CTL) activity against macrophages pulsed with mycobacterial antigen, findings consistent with a protective role against M. tuberculosis. Anti-CD1b antibodies abrogated T cell proliferation, IFN-gamma production, and CTL activity, demonstrating that these T cells are CD1 restricted. IFN-gamma production in response to M. tuberculosis was enhanced by antitransforming growth factor-beta in 8/10 lines, and by IL-15 in 2/10 lines. IFN-gamma production was augmented in a nonantigen-specific manner by IL-12 in 4/8 lines. When live HIV was cocultured with CD1-restricted T cell lines, p24 antigen and proviral DNA were not detected, indicating that the T cells were not infectable with HIV. Vaccination strategies aimed at activation and expansion of M. tuberculosis-reactive CD1-restricted T cells in HIV-infected patients may constitute a novel means to provide protection against tuberculosis, while minimizing the risk of enhancing HIV replication through stimulation of CD4(+) cells.     

B7 and interleukin 12 cooperate for proliferation and interferon gamma production by mouse T helper clones that are unresponsive to B7 costimulation

We have previously shown that dendritic cells isolated after overnight culture, which can express B7 and are potent stimulators of naive T cell proliferation, are relatively poor at inducing the proliferation of a panel of murine T helper 1 (Th1) clones. Maximal stimulation of Th1 clones was achieved using unseparated splenic antigen presenting cells (APC). An explanation for these findings is provided in the present study where we show that FcR+ L cells transfected with B7 stimulate minimal proliferation of Th1 clones in response to anti-CD3 antibodies, in contrast to induction of significant proliferation of naive T cells. However, addition of interleukin 12 (IL-12) to cultures of Th1 cells stimulated with anti-CD3 and FcR+ B7 transfectants resulted in a very pronounced increase in proliferation and interferon gamma (IFN-gamma) production. Exogenous IL-12 did not affect the B7- induced proliferation of naive T cells. This showed that whereas costimulatory signals delivered via B7-CD28 interaction are sufficient to induce significant proliferation of naive T cells activated through occupancy of the T cell receptor, Th1 T cell clones require cooperative costimulation by B7 and IL-12. This costimulation was shown to be specific by inhibition of proliferation and IFN-gamma production using chimeric soluble cytolytic T lymphocyte-associated antigen 4-human IgG1Fc (CTLA4-Ig) and anti-IL-12 antibodies. Furthermore, the significant antigen specific proliferation and IFN-gamma production by Th1 clones observed when splenocytes were used as APC was almost completely abrogated using CTLA4-Ig and anti-IL-12 antibodies. Thus two costimulatory signals, B7 and IL-12, account for the ability of splenic APC to induce maximal stimulation of Th1 clones. IL-10 downregulates the expression of IL-12 by IFN-gamma-stimulated macrophages and this may account largely for t the ability of IL-10 to inhibit APC function of splenic and macrophage APC for the induction of Th1 cell proliferation and IFN-gamma production. Indeed we show that IL-12 can overcome the inhibitory effect of IL-10 for the APC-dependent induction of proliferation and IFN-gamma production by Th1 clones. These results suggest that proliferation by terminally differentiated Th1 clones, in contrast to naive T cells, requires stimulation via membrane-bound B7 and a cytokine, IL-12. It is possible that these signals may result in the activation of unresponsive T cells during an inflammatory response. IL-10, by its role in regulating such innate inflammatory responses, may thus help to maintain these T cells in an unresponsive state.     

A recombinant Leishmania antigen that stimulates human peripheral blood mononuclear cells to express a Th1-type cytokine profile and to produce interleukin 12

Leishmania braziliensis causes cutaneous and mucosal leishmaniasis in humans. Most patients with cutaneous leishmaniasis heal spontaneously and may therefore have developed protective immunity. There appears to be a mixed cytokine profile associated with active cutaneous or mucosal disease, and a dominant T helper (Th)1-type response associated with healing. Leishmanial antigens that elicit these potent proliferative and cytokine responses from peripheral blood mononuclear cells (PBMC) are now being identified. Herein, we report on the cloning and expression of a L. braziliensis gene homologous to the eukaryotic ribosomal protein eIF4A (LeIF) and patient PBMC responses to rLeIF. Patients with mucosal and self-healing cutaneous disease had significantly higher proliferative responses than those with cutaneous lesions. Whereas the parasite lysate stimulated patient PBMC to produce a mixed Th1/Th2-type cytokine profile, LeIF stimulated the production of interferon gamma (IFN-gamma), interleukin 2 (IL-2), and tumor necrosis factor alpha but not IL-4 or IL-10. Recombinant LeIF (rLeIF) downregulated both IL-10 mRNA in the "resting" PBMC of leishmaniasis patients and LPS-induced IL-10 production by patient PBMC. rLeIF also stimulated the production of IL-12 in cultured PBMC from both patients and uninfected individuals. The production of IFN-gamma by patient PBMC stimulated with either rLeIF or parasite lysate was IL-12 dependent, whereas anti-IFN-gamma monoclonal antibody only partially blocked the LeIF-induced production of IL-12. In vitro production of both IFN-gamma and IL-12 was abrogated by exogenous human recombinant IL-10. Therefore, we have identified a recombinant leishmanial antigen that elicits IL-12 production and Th1-type responses in patients as well as IL-12 production in normal human PBMC.     

CD44 is a macrophage binding site for Mycobacterium tuberculosis that mediates macrophage recruitment and protective immunity against tuberculosis

Cell migration and phagocytosis are both important for controlling Mycobacterium tuberculosis infection and are critically dependent on the reorganization of the cytoskeleton. Since CD44 is an adhesion molecule involved in inflammatory responses and is connected to the actin cytoskeleton, we investigated the role of CD44 in both these processes. Macrophage (Mphi) recruitment into M. tuberculosis-infected lungs and delayed-type hypersensitivity sites was impaired in CD44-deficient (CD44(-/-)) mice. In addition, the number of T lymphocytes and the concentration of the protective key cytokine IFN-gamma were reduced in the lungs of infected CD44(-/-) mice. The production of IFN-gamma by splenocytes of CD44(-/-) mice was profoundly increased upon antigen-specific stimulation. Flow cytometry analysis revealed that soluble CD44 can directly bind to virulent M. tuberculosis. Mycobacteria also interacted with Mphi-associated CD44, as reflected by reduced binding and internalization of bacilli by CD44(-/-) Mphis. This suggests that CD44 is a receptor on Mphis for binding of M. tuberculosis. CD44(-/-) mice displayed a decreased survival and an enhanced mycobacterial outgrowth in lungs and liver during pulmonary tuberculosis. In summary, we have identified CD44 as a new Mphi binding site for M. tuberculosis that mediates mycobacterial phagocytosis, Mphi recruitment, and protective immunity against pulmonary tuberculosis.