Advances in the Knowledge of the Underlying Airway Remodeling Mechanisms in Chronic Rhinosinusitis Based on the Endotypes: A Review.

Chronic rhinosinusitis (CRS) is a chronic inflammatory condition of the nasal and paranasal sinus mucosa that affects up to 10% of the population worldwide. CRS is the most representative disease of the upper respiratory tract where airway remodeling occurs, including epithelial damage, thickening of the basement membrane, fibrosis, goblet cell hyperplasia, subepithelial edema, and osteitis. CRS is divided into two phenotypes according to the presence or absence of nasal polyps: CRS with nasal polyp (CRSwNP) and CRS without nasal polyps (CRSsNP). Based on the underlying pathophysiologic mechanism, CRS is also classified as eosinophilic CRS and non-eosinophilic CRS, owing to Type 2 T helper (Th2)-based inflammation and Type 1 T helper (Th1)/Type 17 T helper (Th17) skewed immune response, respectively. Differences in tissue remodeling in CRS are suggested to be based on the clinical phenotype and endotypes; this is because fibrosis is prominent in CRSsNP, whereas edematous changes occur in CRSwNP, especially in the eosinophilic type. This review aims to summarize the latest information on the different mechanisms of airway remodeling in CRS according to distinct endotypes.

A distinct subset of FcγRI-expressing Th1 cells exert antibody-mediated cytotoxic activity.

While a high frequency of Th1 cells in tumors is associated with improved cancer prognosis, this benefit has been attributed mainly to support of cytotoxic activity of CD8+ T cells. By attempting to potentiate antibody-driven immunity, we found a remarkable synergy between CD4+ T cells and tumor-binding antibodies. This surprising synergy was mediated by a small subset of tumor-infiltrating CD4+ T cells that express the high-affinity Fcγ receptor for IgG (FcγRI) in both mouse and human patients. These cells efficiently lyse tumor cells coated with antibodies through concomitant crosslinking of their T cell receptor (TCR) and FcγRI. By expressing FcγRI and its signaling chain in conventional CD4+ T cells, we successfully employed this mechanism to treat established solid cancers. Overall, this discovery sheds new light on the biology of this T cell subset, their function during tumor immunity, and the means to utilize their unique killing signals in immunotherapy.

The Mycobacterium bovis BCG prime-Rv0577 DNA boost vaccination induces a durable Th1 immune response in mice.

Tuberculosis remains a major global health problem and effective vaccines are urgently needed. In this study, we used the combined DNA- and protein-based vaccines of immunodominant antigen Rv0577 to boost BCG and evaluated their immunogenicity in BALB/c mice. Our data suggest that the booster vaccine may substantially enhance the immunogenicity of BCG and strengthen both CD4+ T cell-mediated Th1 and CD8+ T cell-mediated cytolytic responses. Compared with the protein-based vaccine, the DNA-based vaccine can induce more durable Th1 immune response, characterized by high levels of antibody response, proliferation response, percentages of CD4+/CD8+ and cytokine secretion in antigen-stimulated splenocyte cultures. In conclusion, we for the first time, developed a protein- and plasmid DNA-based booster vaccine based on Rv0577. Our findings suggest that antigen Rv0577-based DNA vaccine is immunogenic and can efficiently boost BCG, which could be helpful in the design of an efficient vaccination strategy against TB.

Human Th17 cells comprise heterogeneous subsets including IFN-gamma-producing cells with distinct properties from the Th1 lineage.

Th17 cells have been named after their signature cytokine IL-17 and accumulating evidence indicates their involvement in the induction and progression of inflammatory diseases. In addition to IL-17 single-producing T cells, IL-17/IFN-gamma double-positive T cells are found in significantly elevated numbers in inflamed tissues or blood from patients with chronic inflammatory disorders. Because IFN-gamma is the classical Th1-associated cytokine, the origin and roles of these subsets remain elusive. In this paper, we show that not only IL-17(+)/IFN-gamma(+) but also IFN-gamma(+) (IL-17(-)) cells arise under Th17-inducing condition and have distinct properties from the Th1 lineage. In fact, these populations displayed characteristics reminiscent to IL-17 single-producing cells, including production of IL-22, CCL20, and induction of antimicrobial gene expression from epithelial cells. Live sorted IL-17(+) and Th17-IFN-gamma(+) cells retained expression of IL-17 or IFN-gamma after culture, respectively, whereas the IL-17(+)/IFN-gamma(+) population was less stable and could also become IL-17 or IFN-gamma single-producing cells. Interestingly, these Th17 subsets became "Th1-like" cells in the presence of IL-12. These results provide novel insights into the relationship and functionality of the Th17 and Th1 subsets and have direct implications for the analysis and relevance of IL-17 and/or IFN-gamma-producing T cells present in patients' peripheral blood and inflamed tissues.

Psoriasis vulgaris lesions contain discrete populations of Th1 and Th17 T cells.

The importance of T helper 17 (Th17) cells in inflammation and autoimmunity is now being appreciated. We analyzed psoriasis skin lesions and peripheral blood for the presence of IL-17-producing T cells. We localized Th17 cells predominantly to the dermis of psoriasis skin lesions, confirmed that IL-17 mRNA increased with disease activity, and demonstrated that IL-17 mRNA expression normalized with cyclosporine therapy. IL-22 mRNA expression mirrored IL-17 and both were downregulated in parallel with keratin 16. Th17 cells are a discrete population, separate from Th1 cells (which are also in psoriasis lesions), and Th2 cells. Our findings suggest that psoriasis is a mixed Th1 and Th17 inflammatory environment. Th17 cells may be proximal regulators of psoriatic skin inflammation, and warrant further attention as therapeutic targets.

Interleukin (IL)-23 receptor is a major susceptibility gene for Graves' ophthalmopathy: the IL-23/T-helper 17 axis extends to thyroid autoimmunity.

CONTEXT: IL-23 and its receptor (IL-23R) guide T cells toward the T-helper 17 phenotype. IL-23R single nucleotide polymorphisms (SNPs) have been associated with several autoimmune diseases, including Crohn's disease and rheumatoid arthritis. OBJECTIVE: Our objective was to determine whether variants in the IL-23R gene are associated with Graves' disease (GD) and Graves' ophthalmopathy (GO). DESIGN AND PARTICIPANTS: A total of 216 North American Caucasian GD patients and 368 healthy controls were genotyped for four SNPs spanning the IL-23R gene. SNPs rs11209026 and rs7530511 were genotyped using the TaqMan allelic discrimination assays (Applied Biosystems, Foster City, CA), and SNPs rs2201841 and rs10889677 were genotyped using a fluorescent-based restriction fragment length polymorphism method. RESULTS: The A allele of rs2201841 was present in 78.8% of GD patients with GO and 64.7% of controls [P=1.1x10(-4); odds ratio (OR)=2.04]; the AA genotype was also significantly increased in GO patients compared with controls (62.5 and 41%, respectively; P=1.0x10(-4); OR=2.4). The C allele of rs10889677 was present in 78.6% of GO patients and 64.5% of controls (P=1.3x10(-4); OR=2.03), and the CC genotype was also significantly increased in GO patients vs. controls (62.1 and 41.0%, respectively; P=1.4x10(-4); OR=2.36). The TT genotype of rs7530511 was significantly associated with GD, but not specifically with GO; it was present in 2.5% of GD patients and 0.3% of controls (P=0.02; OR=9.4). The rs11209026 SNP, which is the most strongly associated with Crohn's disease, was not associated with GD or GO in our data set. CONCLUSIONS: Variants in the IL-23R gene are strongly associated with GO. These variants may predispose to GO by changing the expression and/or function of IL-23R, thereby promoting a proinflammatory signaling cascade.

Enhanced immune responses using plasmid DNA replicon vaccine encoding the Hc domain of Clostridium botulinum neurotoxin serotype A.

In current study, the immunogenicity of a plasmid DNA replicon vaccine (pSCARSHc) encoding the Hc domain of Clostridium botulinum neurotoxin serotype A (AHc) was investigated and compared with a conventional plasmid DNA vaccine (pcDNASHc) encoding the same antigen. In vitro, pSCARSHc incorporating Semliki Forest virus (SFV) replicon could express AHc protein and induce apoptosis of transfected cells. Comparison with the conventional plasmid DNA vaccine (pcDNASHc) yielded several interesting results. First, our self-designed pSCARSHc could induce relatively higher AHc-specific antibodies and lymphocyte proliferative responses in immunized Balb/c mice, especially at low doses. Second, while both pSCARSHc and pcDNASHc induced Th2-type immune responses, the ratio of IgG1 to IgG2a was lower in pSCARSHc groups and the Th2- and Th1-type humoral immune responses induced by pSCARSHc were also stronger than that of the pcDNASHc vaccine. Third, it was shown that the sera from pSCARSHc-vaccinated mice conferred more efficient protection than those from pcDNASHc-vaccinated mice by BoNT/A neutralization assay. Finally, mice immunized with pSCARSHc could also elicit more efficient protection against BoNT/A than pcDNASHc. These results indicate that our plasmid DNA replicon vaccine can provide strong immunogenicity and should be a potential alternative strategy to conventional DNA vaccines in developing an efficacious vaccine against C. botulinum neurotoxin serotype A.

Human natural killer T cells are heterogeneous in their capacity to reprogram their effector functions.

BACKGROUND: Natural killer T (NKT) cells are a subset of T cells that help potentiate and regulate immune responses. Although human NKT cell subsets with distinct effector functions have been identified, it is unclear whether the effector functions of these subsets are imprinted during development or can be selectively reprogrammed in the periphery. RESULTS: We found that neonatal NKT cells are predominantly CD4+ and express higher levels of CCR7 and CD62L and lower levels of CD94 and CD161 than adult CD4+ or CD4- NKT cell subsets. Accordingly, neonatal NKT cells were more flexible than adult CD4+ NKT cells in their capacity to acquire Th1- or Th2-like functions upon either cytokine-mediated polarization or ectopic expression of the Th1 or Th2 transcription factors T-bet and GATA-3, respectively. Consistent with their more differentiated phenotype, CD4- NKT cells were predominantly resistant to functional reprogramming and displayed higher cytotoxic function. In contrast to conventional T cells, neither the expression of CXCR3 nor the cytotoxic capacity of neonatal NKT cells could be reprogrammed. CONCLUSIONS AND SIGNIFICANCE: Together, these results suggest that neonatal CD4+, adult CD4+, and adult CD4- NKT may represent unique states of maturation and that some functions of human NKT cells may be developmentally imprinted, while others are acquired similar to conventional T cell subsets during peripheral maturation and differentiation. Given the potent immuno-regulatory functions of NKT cells, these findings have important implications for the development of novel NKT cell-based therapeutics and vaccines.

T cell clones from Schistosoma haematobium infected and exposed individuals lacking distinct cytokine profiles for Th1/Th2 polarisation.

T cell clones were derived from peripheral blood mononuclear cells of Schistosoma haematobium infected and uninfected individuals living in an endemic area. The clones were stimulated with S. haematobium worm and egg antigens and purified protein derivative. Attempts were made to classify the T cell clones according to production of the cytokines IL-4, IL-5 and IFN-gamma. All the T cell clones derived were observed to produce cytokines used as markers for the classification of Th1/Th2 subsets. However, the 'signature' cytokines marking each subset were produced at different levels. The classification depended on the dominating cytokine type, which was having either Th0/1 or Th0/2 subsets. The results indicated that no distinct cytokine profiles for polarisation of Th1/Th2 subsets were detected in these S. haematobium infected humans. The balance in the profiles of cytokines marking each subset were related to infection and re-infection status after treatment with praziquantel. In the present study, as judged by the changes in infection status with time, the T cell responses appeared to be less stable and more dynamic, suggesting that small quantitative changes in the balance of the cytokines response could result in either susceptibility or resistant to S. haematobium infection.

T cell clones from Schistosoma haematobium infected and exposed individuals lacking distinct cytokine profiles for Th1/Th2 polarisation

T cell clones were derived from peripheral blood mononuclear cells of Schistosoma haematobium infected and uninfected individuals living in an endemic area. The clones were stimulated with S. haematobium worm and egg antigens and purified protein derivative. Attempts were made to classify the T cell clones according to production of the cytokines IL-4, IL-5 and IFN-gamma. All the T cell clones derived were observed to produce cytokines used as markers for the classification of Th1/Th2 subsets. However, the 'signature' cytokines marking each subset were produced at different levels. The classification depended on the dominating cytokine type, which was having either Th0/1 or Th0/2 subsets. The results indicated that no distinct cytokine profiles for polarisation of Th1/Th2 subsets were detected in these S. haematobium infected humans. The balance in the profiles of cytokines marking each subset were related to infection and re-infection status after treatment with praziquantel. In the present study, as judged by the changes in infection status with time, the T cell responses appeared to be less stable and more dynamic, suggesting that small quantitative changes in the balance of the cytokines response could result in either susceptibility or resistant to S. haematobium infection

Regulatory functions of self-restricted MHC class II allopeptide-specific Th2 clones in vivo.

We studied T-cell clones generated from grafts of rejecting and tolerant animals and investigated the regulatory function of Th2 clones in vitro and in vivo. To prevent allograft rejection, we treated LEW strain recipient rats of WF strain kidney grafts with CTLA4Ig to block CD28-B7 costimulation. We then isolated epitope-specific T-cell clones from the engrafted tissue, using a donor-derived immunodominant class II MHC allopeptide presented by recipient antigen-presenting cells. Acutely rejected tissue from untreated animals yielded self-restricted, allopeptide-specific T-cell clones that produced IFN-gamma, whereas clones from tolerant animals produced IL-4 and IL-10. Adoptive transfer into naive recipients of Th1 clones, but not Th2 clones, induced alloantigen-specific delayed-type hypersensitivity (DTH) responses. In addition, Th2 clones suppressed DTH responses mediated by Th1 clones in vivo and blocked Th1 cell proliferation and IFN-gamma production in vitro. A pilot human study showed that HLA-DR allopeptide-specific T-cell clones generated from patients with chronic rejection secrete Th1 cytokines, whereas those from patients with stable graft function produce Th2 cytokines in response to donor-specific HLA-DR allopeptides. We suggest that self-restricted alloantigen-specific Th2 clones may regulate the alloimmune responses and promote long-term allograft survival and tolerance.

Bonzo/CXCR6 expression defines type 1-polarized T-cell subsets with extralymphoid tissue homing potential.

Chemokine receptor expression is finely controlled during T-cell development. We show that newly identified chemokine receptor Bonzo/CXCR6 is expressed by subsets of Th1 or T-cytotoxic 1 (Tc1) cells, but not by Th2 or Tc2 cells, establishing Bonzo as a differential marker of polarized type 1 T cells in vitro and in vivo. Priming of naive T cells by dendritic cells induces expression of Bonzo on T cells. IL-12 enhances this dendritic cell-dependent upregulation, while IL-4 inhibits it. In blood, 35-56% of Bonzo+ CD4 T cells are Th1 cells, and 60-65% of Bonzo+ CD8 T cells are Tc1 cells, while few Bonzo+ cells are type 2 T cells. Almost all Bonzo+ Tc1 cells contain preformed granzyme A and display cytotoxic effector phenotype. Most Bonzo+ T cells lack L-selectin and/or CCR7, homing receptors for lymphoid tissues. Instead, Bonzo+ T cells are dramatically enriched among T cells in tissue sites of inflammation, such as rheumatoid joints and inflamed livers. Bonzo may be important in trafficking of effector T cells that mediate type 1 inflammation, making it a potential target for therapeutic modulation of inflammatory diseases.

Upregulation of decidual P-selectin expression is associated with an increased number of Th1 cell populations in patients suffering from spontaneous abortions.

A multicascade of leukocyte-endothelial cell interactions is involved in the trafficking of inflammatory lymphocytes into tissue. The primary contact between leukocytes and endothelium is mediated by selectins. Ligands for P-Selectin are preferentially expressed on Th1 cells and thereby allow migration of these inflammatory cells through the vessel wall. Since a peripheral and local Th1-type cytokine profile is present in spontaneous human abortion (SA), opposed by a Th2 dominant situation in normal pregnancies (NP), we investigated (1) the phenotype of peripheral Th1 cells by flow cytometry, as well as the Th1-type cytokine levels by ELISA, (2) the decidual expression of P- and E-Selectin by immunohistochemistry (IHC), and (3) the phenotype of decidual immunocompetent cells by IHC in patients with NP or SA. We observed enhanced production of IFN-gamma and TNF-alpha in CD8(+), CD3(+), and CD56(+) blood cells, as well as an increase in the number of CCR5(+) cells in patients suffering from SA compared to those with NP. No difference was detectable with respect to the serum levels of the two cytokines. Using IHC methods, we observed increased staining intensity of P-Selectin(+) vessels in samples of SA patients. E-Selectin was only weakly expressed in decidual endothelial cells, with no difference between NP and SA. In SA samples, E-Selectin(+) stromal cells were exclusively present. We further detected increased numbers of decidual CD8(+), CD3(+), CCR5(+), and CD56(+) cells in SA patients. We propose that Th1 lymphocyte migration into decidua is enhanced in SA due to upregulated P-Selectin expression in decidual vessels. This increase of Th1-producing lymphocytes might be involved in the rejection of trophoblasts.

The Th1-Th2 classification of cellular immune responses: concepts, current thinking and applications in haematological malignancy.

The finding that T cell immune responses could be divided into those promoting cell mediated immunity (Th1) and humoral responses (Th2) has had a profound effect on the understanding of immune response generation over the last 15 years. With ever increasing knowledge of the immune system, the model has come under criticism, as not all responses easily fit the classification. Nonetheless, the model still provides a valuable framework on which to base immunological research. In this review we update the model with current thinking regarding the generation and maintenance of immune responses. We then examine how the Th1-Th2 paradigm may be applied in developing new understanding of several topical issues in haematological malignancy-control of graft-versus-host disease; cytokine control of proliferating clones in B and T cell diseases; and suppression of T cell responses in multiple myeloma.

T regulatory cells 1 inhibit a Th2-specific response in vivo.

We recently described a new population of CD4(+) regulatory T cells (Tr1) that inhibits proliferative responses of bystander T cells and prevents colitis induction in vivo through the secretion of IL-10. IL-10, which had been primarily described as a Th2-specific cytokine inhibiting Th1 responses, has displayed in several models a more general immune suppression on both types of effector T cell responses. Using an immediate hypersensitivity model in which BALB/c mice immunized with OVA (alum) normally generate Th2-dominated responses, we examined the ability of OVA-specific Tr1 T cell clones to inhibit OVA-specific cytokines and Ab responses. In contrast to Th2 or Th1 T cell clones, transfer of Tr1 T cell clones coincident with OVA immunization inhibited Ag-specific serum IgE responses, whereas IgG1 and IgG2a synthesis were not affected. This specific inhibition was mediated in part through IL-10 secretion as anti-IL-10 receptor Abs treatment reverted the inhibitory effect of Tr1 T cell clones. Although specifically targeted to IgE responses, Tr1 clones' inhibitory effects were more profound as they affected Ag-specific Th2 cell priming both in term of proliferative responses and cytokine secretion. These results suggest that regulatory T cells may play a fundamental role in maintaining the balance of the immune system to prevent allergic disorders.

Nasal immune system: distinctive Th0 and Th1/Th2 type environments in murine nasal-associated lymphoid tissues and nasal passage, respectively.

The nasal mucosa, an important arm of the mucosal immune system, is the first site of contact with inhaled antigens to induce an IgA response. A major aim of this study was to characterize the Th1 and Th2 cytokine expression of mucosal T cells residing in nasal-associated lymphoid tissue (NALT) and nasal passages (NP) as IgA inductive and effector sites, respectively, at the transcription and cellular levels. An application of single-cell reverse transcription-PCR for analysis of Th1 (IFN-gamma) and Th2 (IL-4 and IL-6) cytokine-specific mRNA revealed the presence of CD4+ T cells with a Th0 profile in NALT, while high numbers of Th2 cytokine-specific mRNA expressed by CD4+ T cells were noted in NP followed by Th1-type cells. NALT CD3+ CD4+ T cells of Th0 type have the capacity to become Th1- and/or Th2-type cells since their activation via the TCR-CD3 complex resulted in the expression of an array of Th1 and Th2 cytokines. CD3+ CD4+ T cells from NP, but not NALT, provide a helper function for the induction of antibody-forming cells including IgA isotype in B cell cultures. These findings suggest that NALT is characterized by a Th0 environment which can gain a Th1 and/or Th2 phenotype. In contrast, NP is considered to be a Th2 dominant site with some Th1 cells that can support the induction of IgA-producing cells.

Differential susceptibility to activation-induced apoptosis among peripheral Th1 subsets: correlation with Bcl-2 expression and consequences for AIDS pathogenesis.

It has been proposed that HIV infection is associated with an imbalance in Th1 and Th2 subsets. Recent reports indicate that Th1 and Th2 effectors differ in their susceptibility to activation-induced apoptosis. To determine whether increased T cell apoptosis in HIV-infected patients contributes to alterations in cytokine synthesis, we performed single-cell analysis of type 1 and type 2 cytokine production by CD4 and CD8 T cells, simultaneously with detection of apoptosis. We demonstrate that a differential alteration in representation of Th1 subsets, rather than commitment of T cells to secrete Th2 cytokines, occurs throughout HIV infection. A significant decrease in the number of IL-2- or TNF-alpha-producing T cells was observed, whereas those producing IFN-gamma remained preserved. Furthermore, there is a gradient of susceptibility to activation-induced apoptosis (IL-2 < IFN-gamma < TNF-alpha) among the different Th1 subsets. This gradient was detected in both CD4 and CD8 subsets, as well as in control donors and HIV-infected patients, in whom the susceptibility to apoptosis of IL-2 and IFN-gamma producers was increased compared with controls. This differential intrinsic apoptosis susceptibility of Th1 effectors was found to be tightly regulated by Bcl-2 expression. In HIV-infected persons, disappearance of IL-2-producing T cells was a good indicator of disease progression and was correlated with the progressive shrinkage of the CD4+ CD45RA+ T cell compartment and a gradual increased susceptibility to activation-induced apoptosis of the IL-2-producing subset. This close relationship between the CD45RA/CD45R0 ratio, the level of type 1 cytokine production, and susceptibility to apoptosis should be considered in HIV-infected patients under antiviral or immune-based therapies.

The ontogeny of class-regulation of CD4+ T lymphocyte populations.

The differential class-regulation of CD4+ T lymphocyte populations is believed to play a major role in determining the qualitative behaviour of the immune system, and in the fate of immune responses in particular. In this article we propose a model for the dynamics of the Th1 and Th2 subpopulations. We put forward the concept of an 'antigenic niche' which allows us to postulate that the key feature underlying the regulation of Th differentiation pathways is the population dynamics of the lymphocytes themselves. Using this model we are able to account for a number of well established experimental observations which were hitherto apparently unrelated and poorly understood. This suggests that our simplified model might be capturing some essential features of the immune system.