Heat Shock Protein-Derived T-Cell Epitopes Contribute to Autoimmune Inflammation in Pediatric Crohn's Disease

Pediatric Crohn''s disease is a chronic auto inflammatory bowel disorder affecting children under the age of 17 years. A putative etiopathogenesis of Crohn''s disease (CD) is associated with disregulation of immune response to antigens commonly present in the gut microenvironment. Heat shock proteins (HSP) have been identified as ubiquitous antigens with the ability to modulate inflammatory responses associated with several autoimmune diseases. The present study tested the contribution of immune responses to HSP in the amplification of autoimmune inflammation in chronically inflamed mucosa of pediatric CD patients. Colonic biopsies obtained from normal and CD mucosa were stimulated with pairs of Pan HLA-DR binder HSP60-derived peptides (human/bacterial homologues). The modulation of RNA and protein levels of induced proinflammatory cytokines were measured. We identified two epitopes capable of sustaining proinflammatory responses, specifically TNF〈 and IFN© induction, in the inflamed intestinal mucosa in CD patients. The responses correlated positively with clinical and histological measurements of disease activity, thus suggesting a contribution of immune responses to HSP in pediatric CD site-specific mucosal inflammation.     

Medical treatment of inflammatory bowel disease: new therapies,new drugs.

Ulcerative colitis, ulcerative proctitis and Crohn''s disease are chronic inflammatory conditions that affect the gastrointestinal tract. Conventional treatment has stressed the role of anti-inflammatory agents to suppress the inflammatory response. New compounds that can deliver 5-aminosalicylic acid to the colon have recently been released in Canada. Metronidazole and azathioprine may also be of benefit in Crohn''s disease. Therapy with cyclosporine and clonidine should be based on the results of further clinical trials. The use of nutritional support as primary therapy in Crohn''s disease appears promising. At present, both pharmacologic and nutritional therapies should be considered in the treatment of inflammatory bowel disease.     

IDO1 and IDO2 Non-Synonymous Gene Variants: Correlation with Crohn's Disease Risk and Clinical Phenotype

BackgroundCrohn''s disease (CD) is a chronic inflammatory disease of the gastrointestinal tract. Genetic polymorphisms can confer CD risk and influence disease phenotype. Indoleamine 2,3 dioxygenase-1 (IDO1) is one of the most over-expressed genes in CD and mediates potent anti-inflammatory effects via tryptophan metabolism along the kynurenine pathway. We aimed to determine whether non-synonymous polymorphisms in IDO1 or IDO2 (a gene paralog) are important either as CD risk alleles or as modifiers of CD phenotype.MethodsUtilizing a prospectively collected database, clinically phenotyped CD patients (n = 734) and non-IBD controls (n = 354) were genotyped for established IDO1 and IDO2 non-synonymous single nucleotide polymorphisms (SNPs) and novel genetic variants elucidated in the literature. Allelic frequencies between CD and non-IBD controls were compared. Genotype-phenotype analysis was conducted. IDO1 enzyme activity was assessed by calculating the serum kynurenine to tryptophan ratio (K/T).ResultsIDO1 SNPs were rare (1.7% non-IBD vs 1.1% CD; p = NS) and not linked to Crohn''s disease diagnosis in this population. IDO1 SNPs did however associate with a severe clinical course, presence of perianal disease, extraintestinal manifestations and a reduced serum K/T ratio during active disease suggesting lower IDO1 function. IDO2 minor allele variants were common and one of them, rs45003083, associated with reduced risk of Crohn''s disease (p = 0.025). No IDO2 SNPs associated with a particular Crohn''s disease clinical phenotype.ConclusionsThis work highlights the functional importance of IDO enzymes in human Crohn''s disease and establishes relative rates of IDO genetic variants in a US population.     

Ly49E Expression on CD8αα-Expressing Intestinal Intraepithelial Lymphocytes Plays No Detectable Role in the Development and Progression of Experimentally Induced Inflammatory Bowel Diseases

The Ly49E NK receptor is a unique inhibitory receptor, presenting with a high degree of conservation among mouse strains and expression on both NK cells and intraepithelial-localised T cells. Amongst intraepithelial-localised T cells, the Ly49E receptor is abundantly expressed on CD8αα-expressing innate-like intestinal intraepithelial lymphocytes (iIELs), which contribute to front-line defense at the mucosal barrier. Inflammatory bowel diseases (IBDs), encompassing Crohn''s disease and ulcerative colitis, have previously been suggested to have an autoreactive origin and to evolve from a dysbalance between regulatory and effector functions in the intestinal immune system. Here, we made use of Ly49E-deficient mice to characterize the role of Ly49E receptor expression on CD8αα-expressing iIELs in the development and progression of IBD. For this purpose we used the dextran sodium sulphate (DSS)- and trinitrobenzenesulfonic-acid (TNBS)-induced colitis models, and the TNF^ΔARE ileitis model. We show that Ly49E is expressed on a high proportion of CD8αα-positive iIELs, with higher expression in the colon as compared to the small intestine. However, Ly49E expression on small intestinal and colonic iIELs does not influence the development or progression of inflammatory bowel diseases.     

Farnesoid X receptor (FXR) activation and FXR genetic variation in inflammatory bowel disease

Background

We previously showed that activation of the bile salt nuclear receptor Farnesoid X Receptor (FXR) protects against intestinal inflammation in mice. Reciprocally, these inflammatory mediators may decrease FXR activation. We investigated whether FXR activation is repressed in the ileum and colon of inflammatory bowel disease (IBD) patients in remission. Additionally, we evaluated whether genetic variation in FXR is associated with IBD.

Methods

mRNA expression of FXR and FXR target gene SHP was determined in ileal and colonic biopsies of patients with Crohn''s colitis (n = 15) and ulcerative colitis (UC; n = 12), all in clinical remission, and healthy controls (n = 17). Seven common tagging SNPs and two functional SNPs in FXR were genotyped in 2355 Dutch IBD patients (1162 Crohn''s disease (CD) and 1193 UC) and in 853 healthy controls.

Results

mRNA expression of SHP in the ileum is reduced in patients with Crohn''s colitis but not in patients with UC compared to controls. mRNA expression of villus marker Villin was correlated with FXR and SHP in healthy controls, a correlation that was weaker in UC patients and absent in CD patients. None of the SNPs was associated with IBD, UC or CD, nor with clinical subgroups of CD.

Conclusions

FXR activation in the ileum is decreased in patients with Crohn''s colitis. This may be secondary to altered enterohepatic circulation of bile salts or transrepression by inflammatory signals but does not seem to be caused by the studied SNPs in FXR. Increasing FXR activity by synthetic FXR agonists may have benefit in CD patients.     

Finger clubbing in inflammatory bowel disease: its prevalence and pathogenesis.

Finger clubbing, measured objectively by using the hyponychial angle, was present in 75 out of 200 (38%) patients with Crohn''s disease, 15 out of 103 (15%) with ulcerative colitis, and two out of 24 (8%) with proctitis. In Crohn''s disease and ulcerative colitis the hyponychial angle was significantly correlated with both disease activity and the extent of fibrosis in the resected specimens from 47 surgically treated patients. The prevalence of finger clubbing in patients with macroscopic disease within the area of the gut innervated by the vagus nerve was significantly higher than that in patients in whom the disease was confined to the distal colon and rectum. Finger clubbing in patients with Crohn''s disease tended to regress after resection of macroscopic disease. It is concluded that finger clubbing is significantly commoner in Crohn''s disease than ulcerative colitis. The focal stimuli for finger clubbing include mucosal inflammatory change and fibrosis mediated by the vagus and possibly other autonomic pathways acting as the afferent arc of a finger-clubbing reflex.     

An antibiotic-responsive mouse model of fulminant ulcerative colitis

Background

The constellation of human inflammatory bowel disease (IBD) includes ulcerative colitis and Crohn''s disease, which both display a wide spectrum in the severity of pathology. One theory is that multiple genetic hits to the host immune system may contribute to the susceptibility and severity of IBD. However, experimental proof of this concept is still lacking. Several genetic mouse models that each recapitulate some aspects of human IBD have utilized a single gene defect to induce colitis. However, none have produced pathology clearly distinguishable as either ulcerative colitis or Crohn''s disease, in part because none of them reproduce the most severe forms of disease that are observed in human patients. This lack of severe IBD models has posed a challenge for research into pathogenic mechanisms and development of new treatments. We hypothesized that multiple genetic hits to the regulatory machinery that normally inhibits immune activation in the intestine would generate more severe, reproducible pathology that would mimic either ulcerative colitis or Crohn''s disease.

Methods and Findings

We generated a novel mouse line (dnKO) that possessed defects in both TGFβRII and IL-10R2 signaling. These mice rapidly and reproducibly developed a disease resembling fulminant human ulcerative colitis that was quite distinct from the much longer and more variable course of pathology observed previously in mice possessing only single defects. Pathogenesis was driven by uncontrolled production of proinflammatory cytokines resulting in large part from T cell activation. The disease process could be significantly ameliorated by administration of antibodies against IFNγ and TNFα and was completely inhibited by a combination of broad-spectrum antibiotics.

Conclusions

Here, we develop to our knowledge the first mouse model of fulminant ulcerative colitis by combining multiple genetic hits in immune regulation and demonstrate that the resulting disease is sensitive to both anticytokine therapy and broad-spectrum antibiotics. These findings indicated the IL-10 and TGFβ pathways synergize to inhibit microbially induced production of proinflammatory cytokines, including IFNγ and TNFα, which are known to play a role in the pathogenesis of human ulcerative colitis. Our findings also provide evidence that broad-spectrum antibiotics may have an application in the treatment of patients with ulcerative colitis. This model system will be useful in the future to explore the microbial factors that induce immune activation and characterize how these interactions produce disease.     

Association of IRGM Gene Mutations with Inflammatory Bowel Disease in the Indian Population

Background

Mutations in the IRGM gene have been associated with Crohn''s disease in several populations but have not been explored in Indian patients with this disease. This study examined the association of IRGM mutations with ulcerative colitis and Crohn''s disease in Indian patients with inflammatory bowel disease.

Methods

The IRGM gene was amplified in four segments and Sanger-sequenced in 101 participants (42 Crohn''s disease, 39 ulcerative colitis, and 20 healthy controls). Ten single nucleotide polymorphisms (SNP) were genotyped in 1200 participants (352 Crohn''s disease, 400 ulcerative colitis, and 448 healthy controls) using Sequenom MassARRAY iPLEX. Disease associations were evaluated for each of the ten SNPs.

Results

Thirty one mutations were identified in the IRGM gene, of which two had not hitherto been reported (150226250- ss947429272 & 150227858- ss947429273). Ten SNPs (6 from the above and 4 from the literature) were evaluated. Significant associations with Crohn''s disease were noted with the T allele of rs1000113 (OR 1.46, 95% CI 1.12–1.90), T allele of rs9637876 (OR 1.25, 95% CI 1.005–1.561) and C allele of rs 13361189 (OR 1.33, 95% CI 1.07–1.669). Two SNPs – rs11747270 and rs180802994 – did not exhibit Hardy-Weinberg equilibrium but were associated with both Crohn''s disease and ulcerative colitis in this population. The remaining SNPs did not show significant associations with either Crohn''s disease or ulcerative colitis.

Conclusions

Association of IRGM gene SNPs with Crohn''s disease is reported for the first time in Indian patients. We also report, for the first time, an association of rs 9637876 in the IRGM gene with Crohn''s disease.     

Molecular reclassification of Crohn's disease by cluster analysis of genetic variants

Background

Crohn''s Disease (CD) has a heterogeneous presentation, and is typically classified according to extent and location of disease. The genetic susceptibility to CD is well known and genome-wide association scans (GWAS) and meta-analysis thereof have identified over 30 susceptibility loci. Except for the association between ileal CD and NOD2 mutations, efforts in trying to link CD genetics to clinical subphenotypes have not been very successful. We hypothesized that the large number of confirmed genetic variants enables (better) classification of CD patients.

Methodology/Principal Findings

To look for genetic-based subgroups, genotyping results of 46 SNPs identified from CD GWAS were analyzed by Latent Class Analysis (LCA) in CD patients and in healthy controls. Six genetic-based subgroups were identified in CD patients, which were significantly different from the five subgroups found in healthy controls. The identified CD-specific clusters are therefore likely to contribute to disease behavior. We then looked at whether we could relate the genetic-based subgroups to the currently used clinical parameters. Although modest differences in prevalence of disease location and behavior could be observed among the CD clusters, Random Forest analysis showed that patients could not be allocated to one of the 6 genetic-based subgroups based on the typically used clinical parameters alone. This points to a poor relationship between the genetic-based subgroups and the used clinical subphenotypes.

Conclusions/Significance

This approach serves as a first step to reclassify Crohn''s disease. The used technique can be applied to other common complex diseases as well, and will help to complete patient characterization, in order to evolve towards personalized medicine.     

Immunotherapy for HIV infections

HIV infection leads to a severe decrease of T CD4 lymphocytes with subsequent development of opportunistic infections. The use of current combination of antivirals has improved the morbidity and morbility of patients. Such treatments are not without severe drawbacks such as toxicity and resistance. Development of additional therapeutic strategies with cytokines, immunomodulators or therapeutic immunizations are currently intensely investigated. The clinical benefit of such strategies is under evaluation. However, these strategies may help to potentiate the immune restoration obtained with antivirals or alternatively to spare or delay the use of antivirals.     

Crohn's disease of the appendix

Granulomatous inflammation typifying Crohn''s disease was centred within or confined to appendices in six patients, two of whom developed lesions attributable to Crohn''s disease elsewhere in the gut. The remaining four patients have remained symptom-free for periods varying from two to six years. Histological evidence of Crohn''s disease was also present in five of 46 appendices available for re-examination in a survey of 63 cases of Crohn''s enterocolitis. It is adduced that appendiceal involvement in Crohn''s disease is not uncommon.     

The use of oral topically acting glucocorticosteroids in the treatment of inflammatory bowel disease.

Glucocorticosteroids are the mainstay of treatment of active Crohn''s disease and ulcerative colitis. These drugs however carry important cosmetic short-term side effects and when used long-term they induce severe irreversible complications. Topically acting glucocorticosteroids, especially budesonide, have been designed to achieve local effect at the site of inflammation without systemic effects of the drug. The first results of clinical trials are promising and budesonide has been shown to have an improved safety with almost comparable efficacy in comparison with prednisolone. The optimal enema dose seems to be 2 mg/100 ml at night whereas 9 mg o.m. is the optimal dose to treat ileal or right ileocolonic Crohn''s disease. Topically acting GCS, like standard GCS are not effective for maintenance of remission of Crohn''s disease or recurrence prevention after resection of the involved Crohn''s segment.     

Atorvastatin Reduces Plasma Levels of Chemokine (CXCL10) in Patients with Crohn's Disease

Background

In Crohn''s disease high tissue expression and serum levels of chemokines and their receptors are known to correlate with disease activity. Because statins can reduce chemokine expression in patients with coronary diseases, we wanted to test whether this can be achieved in patients with Crohn''s disease.

Methodology/Principal Findings

We investigated plasma levels of chemokines (CCL2, CCL4, CCL11, CCL13, CCL17, CCL22, CCL26, CXCL8, CXCL10) and endothelial cytokines (sP-selectin, sE-selectin, sICAM-3, thrombomodulin) in ten Crohn''s disease patients before and after thirteen weeks'' daily treatment with 80 mg atorvastatin. Of the 13 substances investigated, only CXCL10 was found to be significantly reduced (by 34%, p = 0.026) in all of the treated patients. Levels of CXCL10 correlated with C-reactive protein (r = 0.82, p<0.01).

Conclusions/Significance

CXCL10 is a ligand for the CXCR3 receptor, the activation of which results in the recruitment of T lymphocytes and the perpetuation of mucosal inflammation. Hence the reduction of plasma CXCL10 levels by atorvastatin may represent a candidate for an approach to the treatment of Crohns disease in the future.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00454545","term_id":"NCT00454545"}}NCT00454545     

A phase I clinical trial combining dendritic cell vaccination with adoptive T cell transfer in patients with stage IV melanoma

Adoptive transfer of in vitro-expanded tumor-infiltrating lymphocytes (TIL) has shown great clinical benefit in patients with malignant melanoma. TIL therapy itself has little side effects, but conditioning chemo- or radiotherapy and postinfusion interleukin 2 (IL-2) injections are associated with severe adverse advents. We reasoned that combining TIL infusion with dendritic cell (DC) vaccination could circumvent the need for conditioning and IL-2 support and thus represent a milder treatment approach. Eight patients with stage IV melanoma were enrolled in the MAT01 study, consisting of vaccination with autologous tumor-lysate-loaded DC, followed by TIL infusion. Six of eight patients were treated according to protocol, while one patient received only TIL and one only DC. Treatments were well tolerated with a single grade 3 adverse event. The small study size precludes analysis of clinical responses, though interestingly one patient showed a complete remission and two had stable disease. Analysis of the infusion products revealed that mature DC were generated in all cases. TIL after expansion were CD3+ T cells, dominated by effector memory CD8+ cytotoxic T cells. Analysis of the T cell receptor repertoire revealed presence of highly dominant clones in most infusion products, and many of these could be detected in the circulation for weeks after T cell transfer. Here, we report the first combination of DC vaccination and TIL infusion in malignant melanoma. This combined treatment was safe and feasible, though after evaluating both clinical and immunological parameters, we expect that administration of lymphodepleting chemotherapy and IL-2 will likely increase treatment efficacy.     

小肠CT及双气囊小肠镜诊断克罗恩病患者的差异性分析

目的:探究小肠CT及双气囊小肠镜诊断克罗恩病患者的差异性。方法:选择2017年4月至2019年3月于我院接受治疗的60例克罗恩病患者,分别实施小肠CT及双气囊小肠镜检测,对比两种检测方式对克罗恩病患者诊断准确率及病变范围、病变位置、活动度和并发症的检测差异。结果:CT检出克罗恩病的准确率96.67%,双气囊小肠镜检出克罗恩病的准确率为93.33%,其差异无统计学意义(P>0.05)。小肠CT主要表现为肠腔狭窄50例(83.33%),肠壁增厚52例(86.67%),肠外淋巴结46例(76.67%),肠系膜水肿及血管改变21例(35.00%),肠外炎症10例(16.67%),瘘管3例(5.00%),瘘道1例(1.67%);双气囊小肠镜表现为环形溃疡、不规则溃疡、环状溃疡等共计46例(76.67%),阿弗他溃疡22例(36.67%),黏膜充血、水肿等26例(43.33%),结节样增生6例(10.00%),小肠肠腔节段性狭窄16例(26.67%),假性息肉9例(15.00%);经病理学检测表现为淋巴细胞、中性粒细胞、嗜酸性粒细胞等炎性浸润,淋巴组织及肉芽组织出现增生小肠CT发现肠外炎症、瘘道、瘘管等合计14例,而双气囊小肠镜未发现并发症。结论:相比于双气囊小肠镜,小肠CT能够更为准确的判断克罗恩病患者是否处于炎症状态,也能够更有效的发现肠外并发症的存在,但小肠CT及双气囊小肠镜联合应用监测效果更佳。     

Immunoresponsiveness in Ulcerative Colitis and Crohn's Disease—Effect of Colectomy and Suppression of Disease Activity

We evaluated the effect of medically induced symptomatic disease improvement on in vitro tests of cell-mediated immune responses in 33 patients with Crohn''s disease. When results obtained in 17 patients with ulcerative colitis were compared with those of 10 patients with ulcerative colitis who had undergone a colectomy, no significant correlation was detected between individual clinical and laboratory variables or the Crohn''s disease activity index and in vitro tests of cell-mediated immunity. A different pattern emerged from the longitudinal tests of cell-mediated immunity: when these test results were initially abnormal in patients with Crohn''s disease, clinical improvement as assessed by the Crohn''s disease activity index was associated with normalizing cell-mediated immunity. In contrast, when the test results were initially normal, clinical improvement was not associated with any change in the immune response. Following colectomy in patients with ulcerative colitis, some abnormalities of suppressed immune responses remained, although patients were cured of their disease. Factors other than clinical disease activity may be responsible for the suppressed immunoresponsiveness in some patients with inflammatory bowel disease, and variable changes in cell-mediated immunity occur after both surgical and medical treatment.     

Th2 predominance and CD8+ memory T cell depletion in patients with severe acute respiratory syndrome

The immune spectrum of severe acute respiratory syndrome (SARS) is poorly understood. To define the dynamics of the immune spectrum in SARS, serum levels of cytokines, chemokines, immunoglobulins, complement and specific antibodies against SARS-associated coronavirus (SARS-CoV) were assayed by enzyme-linked immunosorbent assay (ELISA), and phenotypes of peripheral lymphocytes were analyzed by flow cytometry in 95 SARS-infected patients. Results showed that interleukin (IL)-10 and transforming growth factor beta (TGF-beta) were continuously up-regulated during the entirety of SARS. Regulated on activation normally T cell-expressed and secreted (RANTES) levels were decreased, while monocyte chemoattractant protein-1 (MCP-1) was elevated in acute patients. Immunoglobulins and complement were elevated during the first month of SARS. Both serum-positive rates and titers of specific IgM and IgG antibodies responding to SARS-CoV peaked at days 41-60 from the onset of SARS. CD4+ and CD8+ T lymphocytes decreased significantly in acute-phase. CD3+CD8+CD45RO+ T lymphocytes were decreased by 36.78% in the convalescent patients. Conclusion: SARS-CoV seemed to elicit effective humoral immunity but inhibited cellular immunity, especially CD8+ memory T lymphocytes over time. Prolonged overproduction of IL-10 and TGF-beta may play an important role in the disease.     

CD1-restricted recognition of exogenous and self-lipid antigens by duodenal gammadelta+ T lymphocytes

Gammadelta T cells are present in the mucosal intestinal epithelia and secrete factors necessary to maintain tissue integrity. Ags recognized by these cells are poorly defined, although in mice non-classical MHC class I molecules have been implicated. Since MHC class I-like CD1 receptors are widely expressed at the surface of epithelial and dendritic intestinal cells and have the capacity to present lipid Ags to T cells, we hypothesized that these molecules might present autologous and/or exogenous phospholipids to intestinal gammadelta T lymphocytes. Intraepithelial T lymphocytes from normal human duodenal mucosal biopsies were cloned and exposed to natural and synthetic phospholipids using CD1a-, CD1b-, CD1c- or CD1d-transfected C1R lymphoblastoid or HeLa cell lines as APCs. Their cytolytic properties and regulatory cytokine secretion were also examined. Most clones obtained from duodenal mucosa (up to 70%) were TCRalphabeta+, and either CD4+ or CD8+, whereas 20% were CD4-CD8- (6 clones) or TCRgammadelta+ (12 clones). A relevant percentage (up to 66%) of TCRgammadelta+ but few (<5%) TCRalphabeta+ T cell clones responded to synthetic and/or natural phospholipids presented by CD1 molecules, as measured by both [(3)H]thymidine incorporation and IL-4 release assays. A Th1-like cytolytic and functional activity along with the ability to secrete regulatory cytokines was observed in most phospholipid-specific gammadelta T cell clones. Thus, a substantial percentage of TCRgammadelta+ but few TCRalphabeta+ from human duodenal mucosa recognize exogenous phospholipids in a CD1-restricted fashion. This adaptive response could contribute to mucosal homeostasis, but could also favor the emergence of inflammatory or allergic intestinal diseases.     

Local expansion of allergen-specific CD30+Th2-type gamma delta T cells in bronchial asthma.

BACKGROUND: T lymphocytes infiltrating airways during the allergic immune response play a fundamental role in recruiting other specialized cells, such as eosinophils, by secreting interleukin 5 (IL-5), and promoting local and systemic IgE synthesis by producing IL-4. Whether these presumed allergen-specific T cells are of mucosal or systemic origin is still a matter of conjecture. MATERIALS AND METHODS: Immunophenotype, IL-4 production, and in vitro proliferative response to specific or unrelated allergens were analyzed in the bronchoalveolar lavage (BAL) fluid lymphocyte suspensions obtained from untreated patients with allergic asthma. Healthy subjects and patients affected by pulmonary sarcoidosis, a granulomatous lung disease characterized by infiltrating Th1 CD4+ lymphocytes, served as controls. RESULTS: The proportions of gamma delta T lymphocytes, mostly CD4+ or CD4- (-)CD8-, was higher in asthmatic subjects than in controls (p < 0.05). Most BAL gamma delta CD4+ lymphocytes of asthmatic patients displayed the T cell receptor (TCR)-gamma delta V delta 1 chain. While CD30 antigen coexpression on the surface of BAL alpha beta(+) T lymphocytes was low (ranging from 5 to 12%), about half of pulmonary gamma delta T cells coexpressed it. These cells produced IL-4 and negligible amounts of interferon-gamma (IFN gamma), and proliferated in vitro in response to purified specific but not unrelated allergens. In contrast, control or sarcoidosis gamma delta T cells never displayed the CD30 surface molecule or produced significant quantities of IL-4. CONCLUSIONS: These findings not only confirm our previous hypothesis that the allergen-specific Th2-type lymphocytes found in the lungs of asthmatic patients are gamma delta T cells belonging to airway mucosal immunocytes, but also strongly support the notion that asthma is a local rather than a systemic disease.     

Rapid memory CD8+ T-lymphocyte induction through priming with recombinant Mycobacterium smegmatis

The most promising vaccine strategies for the induction of cytotoxic-T-lymphocyte responses have been heterologous prime/boost regimens employing a plasmid DNA prime and a live recombinant-vector boost. The priming immunogen in these regimens must elicit antigen-specific memory CD8+ T lymphocytes that will expand following the boosting immunization. Because plasmid DNA immunogens are expensive and their immunogenicity has proven disappointing in human clinical trials, we have been exploring novel priming immunogens that might be used in heterologous immunization regimens. Here we show that priming with a prototype recombinant Mycobacterium smegmatis strain expressing human immunodeficiency virus type 1 (HIV-1) gp120-elicited CD4+ T lymphocytes with a functional profile of helper cells as well as a CD8+ T-lymphocyte population. These CD8+ T lymphocytes rapidly differentiated to memory cells, defined on the basis of their cytokine profile and expression of CD62L and CD27. Moreover, these recombinant-mycobacterium-induced T lymphocytes rapidly expanded following boosting with a recombinant adenovirus expressing HIV-1 Env to gp120-specific CD8+ T lymphocytes. This work demonstrates a remarkable skewing of recombinant-mycobacterium-induced T lymphocytes to durable antigen-specific memory CD8+ T cells and suggests that such immunogens might be used as priming vectors in prime/boost vaccination regimens for the induction of cellular immune responses.