T-cell co-stimulatory molecules: novel targets for the treatment of allergic airway disease.

The first two articles in this series discussed the fundamental concept of T-cell co-stimulation as a key event in the induction of any immune response, in addition to reviewing the current data on the role of co-stimulatory molecules for the induction and progression of allergic airway diseases. Based on these considerations, this final edition will delineate and discuss novel strategies for the prevention and/or therapy of allergic diseases based upon the modulation of co-stimulation.     

T-cell characterization in chronic allergic eye disease

Chronic allergic eye disease encompasses several disorders, but it is vernal keratoconjunctivitis (VKC) and atopic keratoconjunctivitis (AKC) that have sight-threatening sequelae. T cells, eosinophils, and mast cells are all found in the conjunctiva, and are thought to play a role in disease pathogenesis. Recently, the conjunctival epithelium has also been considered to play a key role. New and effective therapeutic strategies for the future for these patients depend on achieving a greater understanding of the roles and interactions of the cell populations in these sight-threatening disorders.     

Association between chlamydial infection and coronary artery disease

Recent epidemiological studies have demonstrated the association between Chlamydia pneumoniae infection and coronary atherosclerosis. However, the relationship is less clear in the Japanese population. Serum IgA and IgG antibodies to Chlamydia-specific lipopolysaccharide were measured by enzyme-linked immunosorbent assay in 152 consecutive patients(112 males, 40 females, mean age 57 years)who underwent coronary angiography. Patients(n = 123)with coronary artery disease(CAD)were defined as having more than 50% diameter stenosis in at least one major coronary artery. The control group(n = 29) had normal coronary angiograms. In the CAD group, there was a high tendency of prevalence of IgA(20% vs 7%, p = 0.08)and IgG(54% vs 34%, p = 0.052). Prevalence of either IgA or IgG was significantly higher (59% vs 38%, p = 0.045) compared with the control group. Although the index of IgA antibody was not significantly different between the CAD and control groups(median 0.52 vs 0.36, p = 0.19), the index of IgG antibody was significantly higher in the CAD group than in the control group(median 1.29 vs 0.82, p = 0.026). The odds ratios for CAD were 3.4[95% confidence interval(CI)0.6-18.7]for the prevalence of IgA, 2.3(95% CI 0.9-5.2)for the prevalence of IgG, and 2.3(95% CI 1.0-5.2)for the prevalence of either IgA or IgG. Patients with CAD tended to have high prevalence of antibodies to Chlamydia spp, and these findings suggest an association between chlamydial infection and coronary atherosclerosis in the Japanese population.     

Effect of interferon-gamma on allergic airway responses in interferon-gamma-deficient mice

Interferon (IFN)-gamma reduces airway responses after allergen challenge in mice. The mechanisms of this effect are not clear. These studies investigate whether IFN-gamma can reverse prolonged airway responses after allergen challenge in IFN-gamma-deficient (IFN-gammaKO) mice. Sensitized mice (IFN-gammaKO and wild-type [WT]) were challenged with ovalbumin. Airway responsiveness, eosinophils in bronchoalveolar lavage fluid, and lung lymphocyte subsets (CD4(+) and CD8(+)) were measured 24 hours and 8 weeks after challenge. In further experiments, we treated IFN-gammaKO mice with recombinant IFN-gamma starting 4 weeks after the challenge for 1 week or 4 weeks. Airway responsiveness, bronchoalveolar lavage eosinophils, and lung CD4(+) cells were increased 8 weeks after challenge in IFN-gammaKO but not WT mice. IFN-gamma treatment returned lung CD4(+) cell numbers to values obtained in unchallenged mice. One week of IFN-gamma treatment also returned airway responsiveness to baseline levels; however, 4-week treatment with IFN-gamma failed to decrease airway responsiveness below levels observed in untreated animals. This suggests that IFN-gamma plays an essential role in reversing allergen-induced airway inflammation and hyperresponsiveness and that it may have dual actions on the latter. Observations that IFN-gamma reverses airway responses, even when administered after challenge, suggests that IFN-gamma treatment could control allergic disease, including asthma.     

The potential for vaccine development against chlamydial infection and disease

Chlamydia trachomatis and Chlamydia pneumoniae appear to share a common immunobiology with about 80% of their protein coding genes being orthologs. Progress in DNA vaccine development for C. trachomatis suggests that such a subunit approach may prove useful for C. pneumoniae. The recent finding that it is possible to select for chlamydiae with targeted mutations in key metabolic genes together with the new knowledge of the chlamydia genome also suggests that it may be possible to develop live attenuated strains of chlamydiae for use as vaccine.     

Interleukin-12 therapy of cutaneous T-cell lymphoma induces lesion regression and cytotoxic T-cell responses.

Progression of cutaneous T-cell lymphoma (CTCL) is associated with profound defects in cell-mediated immunity and depressed production of cytokines, which support cell-mediated immunity. Because we have observed marked defects in interleukin-12 (IL-12) production in CTCL and because IL-12 is critical for antitumor cytotoxic T-cell responses, we initiated a phase I dose escalation trial with recombinant human IL-12 (rhIL-12) where patients received either 50, 100, or 300 ng/kg rhIL-12 twice weekly subcutaneously or intralesionally for up to 24 weeks. Ten patients were entered: 5 with extensive plaque, 3 with Sezary syndrome, and 2 with extensive tumors with large cell transformation. One patient with Sezary syndrome dropped out after 1 week for personal reasons. Subcutaneous dosing resulted in complete responses (CR) in 2 of 5 plaque and partial responses (PR) in 2 of 5 plaque, and 1 of 2 Sezary syndrome (overall response rate CR+PR 5 of 9, 56%). A minor response also occurred in 1 of 5 plaque patients. Intralesional dosing resulted in individual tumor regression in 2 of 2 patients. Biopsy of regressing lesions showed a significant decrease in the density of the infiltrate in all cases and complete resolution of the infiltrate among those with clinical lesion resolution. An increase in numbers of CD8-positive and/or TIA-1-positive T cells were observed on immunohistochemical analysis of skin biopsy specimens obtained from regressing skin lesions. Adverse effects of rhIL-12 on this regimen were minor and limited and included low-grade fever and headache. One patient discontinued rhIL-12 at week 6 because of depression. These results suggest that rhIL-12 may augment antitumor cytotoxic T-cell responses and may represent a potent and well-tolerated therapeutic agent for CTCL.     

Questionnaire responses that predict airway response to hypertonic saline

BACKGROUND: Airway hyperresponsiveness to hypertonic saline (HS) is associated with airway inflammation. We investigated if responsiveness to HS was predicted by asthma symptoms in the last 3 months. OBJECTIVES: To investigate if responsiveness to HS can be estimated by questionnaire items investigating asthma symptoms of the last 3 months. METHODS: Six hundred and four patients with physician-diagnosed asthma being assessed for asthma severity were studied. Bronchial provocation with 4.5% saline was performed, and a questionnaire was administered. The response to 4.5% saline was reported as the provoking dose to cause a 15% fall in the forced expiratory volume in 1 s FEV(1) (PD(15)) and the response-dose ratio (RDR). RESULTS: Based on the GINA guidelines, asthma severity was intermittent in 497 patients, mild in 107 patients, moderate in 3 patients and severe in 1 patient. A PD(15) to 4.5% saline was recorded in 234 of the 604. Questions on self-recognition of asthma, dust as a trigger, food as a trigger, and frequency of bronchodilator use were significant predictors for a PD(15), and currently taking steroids decreased the likelihood of a positive response to 4.5% saline. Using a multiple-linear regression model, a difference in the RDR could be calculated between those who answered positively compared with the reference group, who answered negatively. This difference could be used as a guide for predicting abnormal reactivity. An increase in RDR in response to 4.5% saline, compared with the reference group, was demonstrated in the presence of self-recognition of asthma severity, dust and cats as a trigger or use of bronchodilator during sleep hours. CONCLUSIONS: Because of the high positive predictive value of HS for identifying patients with asthma it might be that the need for bronchodilator use at night not only predicts airway hyperresponsiveness to HS, it also could reflect the severity of asthma.     

Abnormal phytohemagglutinin-induced T-cell proliferative responses in Hodgkin's disease

Optimal conditions were established for evaluating the phytohemagglutinin-induced proliferative responses of purified peripheral blood T lymphocytes. This assay was utilized to determine whether T cells (in the absence of monocytes and serum inhibitory factors) from patients with Hodgkin's disease were defective in their ability to proliferative in response to optimal (50 microgram/ml) and suboptimal (25 and 12.5 microgram/ml) concentrations of phytohemagglutinin. T cells from 6 of 12 untreated patients exhibited 6- day proliferative responses below the range of 15 control subjects using optimal mitogen concentrations, and 9 of 12 patients exhibited subnormal responses using lower concentrations. Kinetic analyses indicated that the abnormal T-cell proliferative responses were characterized by peak proliferation occurring at day 4 or 5, rather than day 6. The observed abnormalities were not related to elevations in the proportions of T cells bearing surface receptors for IgG (T gamma Cells). Our results suggest that intrinsic functional T-cell defects contribute to the impaired immunity associated with Hodgkin's disease.     

PTEN deficiency in mast cells causes a mastocytosis-like proliferative disease that heightens allergic responses and vascular permeability

Kit regulation of mast cell proliferation and differentiation has been intimately linked to the activation of phosphatidylinositol 3-OH kinase (PI3K). The activating D816V mutation of Kit, seen in the majority of mastocytosis patients, causes a robust activation of PI3K signals. However, whether increased PI3K signaling in mast cells is a key element for their in vivo hyperplasia remains unknown. Here we report that dysregulation of PI3K signaling in mice by deletion of the phosphatase and tensin homolog (Pten) gene (which regulates the levels of the PI3K product, phosphatidylinositol 3,4,5-trisphosphate) caused mast cell hyperplasia and increased numbers in various organs. Selective deletion of Pten in the mast cell compartment revealed that the hyperplasia was intrinsic to the mast cell. Enhanced STAT5 phosphorylation and increased expression of survival factors, such as Bcl-XL, were observed in PTEN-deficient mast cells, and these were further enhanced by stem cell factor stimulation. Mice carrying PTEN-deficient mast cells also showed increased hypersensitivity as well as increased vascular permeability. Thus, Pten deletion in the mast cell compartment results in a mast cell proliferative phenotype in mice, demonstrating that dysregulation of PI3K signals is vital to the observed mast cell hyperplasia.     

Association of Mycoplasma pneumoniae infection with coronary artery disease and its interaction with chlamydial infection

Mycoplasma pneumoniae (MP) seropositivity was reported to be associated with coronary events. MP organisms were detected with Chlamydia pneumoniae (CP) in coronary plaques. We investigated MP and CP seropositivity in 549 patients undergoing coronary angiography. Coronary artery disease (CAD) was found in 396 patients, of whom 154 had myocardial infarction (MI). MP seropositivity was more prevalent in patients with CAD than without CAD (14% versus 6%, P < 0.01). The highest prevalence was found in patients with MI. In contrast, the prevalence of CP seropositivity was similar in patients with and without CAD (62% versus 59%). To clarify interaction with CP infection, 549 patients were divided into two groups with and without CP seropositivity. Among patients with CP seropositivity, MP seropositivity was more prevalent in patients with CAD than without CAD (17% versus 5%, P < 0.01), whereas among patients without CP seropositivity, MP seropositivity did not differ between patients with and without CAD (9% versus 6%). In multivariate analysis, MP seropositivity was associated with CAD only in patients with CP seropositivity (odds ratio = 5.1, 95% CI = 1.8-14.9). Thus, MP seropositivity was associated with CAD. However, this association was confined to patients with CP seropositivity. Coinfection by MP and CP may be an important cofactor for CAD.     

Immunotherapy through T-cell receptor gene transfer induces severe graft-versus-host disease

Evaluation of: Bendle GM, Linnemann C, Hooijkaas AI et al.: Lethal graft-versus-host disease in mouse models of T cell receptor gene therapy. Nat. Med. 16(5), 565-570 (2010). Graft-versus-host disease is commonly associated with allogeneic hematopoietic cell transplantation, as it is the major complication. This article reports that, after immunotherapy with lymphocytes that have been transduced with T-cell receptor (TCR) genes of known specificity, graft-versus-host disease can occur through TCR gene transfer. This autoimmune pathology occurs through the formation of self-reactive TCRs as a result of one chain of the transduced TCR cross-pairing with an endogenous TCR. Certain adjustments in the design of gene therapy vectors may help reduce the risk of such autoimmune phenomena.     

Influence of lipopolysaccharide exposure on airway function and allergic responses in developing mice

Exposure to endotoxin has been associated with an exacerbation of asthmatic responses in humans and animal models. However, recent evidence suggests that microbial exposure in early life may protect from the development of asthma and atopy. In this study, we sought to evaluate the effects of lipopolysaccaride (LPS) on airway function in developing mice. In addition, we evaluated the influence of LPS on subsequent allergen sensitization and challenge. Under light anesthesia, 2-3-week-old Balb/c mice received a single intranasal instillation of LPS or sterile physiologic saline. Measurements of airway function were obtained in unrestrained animals, using whole-body plethysmography. Airway responsiveness was expressed in terms of % enhanced pause (Penh) increase from baseline to aerosolized methacholine (Mch). In additional studies, we assessed the functional and cellular responses to ovalbumin sensitization and challenge following prior exposure to LPS.We found that exposure to LPS induced transient airway hyperresponsiveness to Mch. These functional changes were associated with the recruitment of neutrophils and lymphocytes into the bronchoalveolar lavage (BAL) fluid. Airway responsiveness after allergen sensitization and challenge was decreased by prior exposure to LPS. The analysis of BAL cells and cytokines (interferon-gamma and interleukin-4) did not reveal alterations in the overall Th1/Th2 balance.Our findings suggest that LPS leads to airway hyperresponsiveness in developing mice, and may protect against the development of allergen-driven airway dysfunction.     

Novel recombinant interleukin-13 peptide-based vaccine reduces airway allergic inflammatory responses in mice

RATIONALE: Interleukin (IL)-13 plays a pivotal role in the pathogenesis of allergic asthma. Passive administration of its monoclonal antibody or soluble receptor to block overproduced IL-13 has been proven to be effective in controlling airway allergic responses in animal models, but these approaches have disadvantages of short half-lives, high costs, and possible adverse effects. OBJECTIVES: We sought to develop a novel therapeutic strategy through constructing an IL-13 peptide-based vaccine for blocking IL-13 on a persistent effect basis and to evaluate its in vivo effects using a murine model. METHODS: To break self-tolerance, truncated hepatitis B core antigen was used as a carrier. Vaccine was prepared by inserting a peptide derived from the receptor binding site of mouse IL-13 into the immunodominant epitope region of the carrier using gene recombination methods. Mice received vaccine subcutaneously three times, and then subjected to intraperitoneal sensitization and intranasal challenge with ovalbumin. Control animals received carrier or saline in place of vaccine. MEASUREMENTS AND MAIN RESULTS: The vaccine presented as virus-like particles and induced sustained and high titered IL-13-specific IgG without the use of conventional adjuvant. Vaccination significantly suppressed ovalbumin-induced inflammatory cell number, and IL-13 and IL-5 levels in bronchoalveolar lavage fluids. Serum total and ovalbumin-specific IgE were also significantly inhibited. Moreover, allergen-induced goblet cell hyperplasia, lung tissue inflammatory cell infiltration, and pulmonary hyperresponsiveness to inhaled methacholine were significantly suppressed in vaccinated mice. CONCLUSIONS: Our data indicate that IL-13 peptide-based vaccines could be an effective therapeutic approach in the treatment of asthma.     

DNA vaccination induces WT1-specific T-cell responses with potential clinical relevance

The Wilms tumor antigen, WT1, is associated with several human cancers, including leukemia. We evaluated WT1 as an immunotherapeutic target using our proven DNA fusion vaccine design, p.DOM-peptide, encoding a minimal tumor-derived major histocompatibility complex (MHC) class I-binding epitope downstream of a foreign sequence of tetanus toxin. Three p.DOM-peptide vaccines, each encoding a different WT1-derived, HLA-A2-restricted epitope, induced cytotoxic T lymphocytes (CTLs) in humanized transgenic mice expressing chimeric HLA-A2, without affecting hematopoietic stem cells. Mouse CTLs killed human leukemia cells in vitro, indicating peptide processing/presentation. Low numbers of T cells specific for these epitopes have been described in cancer patients. Expanded human T cells specific for each epitope were lytic in vitro. Focusing on human WT1(37-45)-specific cells, the most avid of the murine responses, we demonstrated lysis of primary leukemias, underscoring their clinical relevance. Finally, we showed that these human CTL kill target cells transfected with the relevant p.DOM-peptide DNA vaccine, confirming that WT1-derived epitopes are presented to T cells similarly by tumors and following DNA vaccination. Together, these data link mouse and human studies to suggest that rationally designed DNA vaccines encoding WT1-derived epitopes, particularly WT1(37-45), have the potential to induce/expand functional tumor-specific cytotoxic responses in cancer patients.     

Intestinal T-cell responses to high-molecular-weight glutenins in celiac disease

BACKGROUND & AIMS: The chronic, small intestinal inflammation that defines celiac disease is initiated by a HLA-DQ2 restricted T-cell response to ingested gluten peptides after their in vivo deamidation by tissue transglutaminase (TG2). To date, celiac disease can only be treated by a lifelong abstinence from foods that contain wheat, rye, or barley; better therapeutic options are hence needed. An attractive target would be to identify nontoxic wheat cultivars or components thereof with intact baking qualities. Because these qualities are mainly determined by the high molecular weight (HMW) glutenin proteins of gluten, it is critical to know if these proteins are toxic or, more specifically, if they will trigger the activation of T cells in the celiac lesion. METHODS: Different, highly purified HMW glutenins were isolated from wheat cultivars or expressed as recombinant proteins. The proteins were first tested for recognition by a large panel of gluten-specific T-cell lines established from celiac lesions and then applied during ex vivo challenges of celiac biopsies to allow for a direct identification of HMW specific T cells. RESULTS: Intestinal T-cell responses to TG2-deamidated HMW glutenins but not the corresponding native proteins were detectable in 9 of the 22 adult and childhood celiac disease patients tested. CONCLUSIONS: T cells within celiac lesions frequently recognize deamidated HMW glutenin proteins. This finding questions the possibility of implementing these proteins in novel food items destined to be nontoxic for celiac disease patients.     

Acute and chronic airway responses to viral infection: implications for asthma and chronic obstructive pulmonary disease

Despite the high clinical impact of established and emerging respiratory viruses, some critical aspects of the host response to these pathogens still need to be defined. In that context, we aimed at two major issues: first, what are the innate immune mechanisms that control common respiratory viral infections; and second, whether these mechanisms also cause long-term airway disease. Using a mouse model of viral bronchiolitis, we found that antiviral defense depends at least in part on a network of mucosal epithelial cells and macrophages specially programmed for immune-response gene expression. When this network is compromised, the host is highly susceptible to infection, but network components can be engineered to provide increased resistance to infection. Similar alterations appear in asthma and chronic bronchitis/chronic obstructive pulmonary disease, suggesting that evolving attempts to improve antiviral defense may also lead to inflammatory airway disease. Indeed, in genetically susceptible mice, respiratory paramyxoviruses cause a "hit and run" phenomenon that is manifested by the development of a permanent airway disease phenotype long after the infection has cleared. The phenotype can be segregated into individual traits to achieve more precise definition of just how viruses reprogram host behavior. Identifying specific components of the mucosal immune system that manifest an aberrant antiviral response may thereby allow for adjusting this response to improve acute and chronic outcomes after viral infection.     

Latent tuberculosis infection treatment and T-cell responses to Mycobacterium tuberculosis-specific antigens

RATIONALE: There is currently no available test for monitoring the effect of treatment of latent tuberculosis infection (LTBI) to indicate cure or predict risk of subsequent progression to disease. OBJECTIVE: We used the T-SPOT.TB assay, which measures T-cell interferon-gamma responses to the Mycobacterium tuberculosis-specific peptides early secretory antigenic target 6-kD protein (ESAT-6) and culture filtrate protein 10 (CFP-10), to determine the effect of LTBI treatment on these responses. METHODS: A total of 226 tuberculosis contacts with positive T-SPOT.TB results underwent repeat testing on LTBI treatment completion. The majority (96%) received 6 months of isoniazid. The pre- and post-treatment T-SPOT.TB results were analyzed according to the combined and separate responses to ESAT-6 and CFP-10 antigens. RESULTS: The T-SPOT.TB reverted to negative in 85 (37.6%) contacts at treatment completion. Treatment had a significant effect on the response to CFP-10 (p < 0.001; reversion rate, 48.6%), but not on the response to ESAT-6 (p = 0.081; reversion rate, 21.6%). The median number of spot-forming cells (SFCs)/2.5 x 10(5) peripheral blood mononuclear cells (PBMCs) pre- and post-treatment was 6 versus 4.5 for ESAT-6 (p = 0.116) and 11 versus 4 for CFP-10 (p < 0.001). There was a significant difference between the change (fall) in the pre- and post-treatment responses to CFP-10 (6 SFCs/2.5 x 10(5) PBMCs) and ESAT-6 (0 SFCs/2.5 x 10(5) PBMCs; p < 0.001). Significantly different age-related T-cell responses to the two antigens were found. CONCLUSION: LTBI treatment had a differential effect on T-cell responses to ESAT-6 and CFP-10 as measured by the T-SPOT.TB. The quantitative response to CFP-10 may be a useful LTBI treatment-monitoring tool.