Th1-like Cytokine Profile Research Articles

First evidence of systemic infection and specific cytotoxic T lymphocyte immune response evoked by oral infection with recombinant Salmonella enterica serovar Albany-Ovalbumin in C57BL/6 mice

Our group isolated Salmonella enterica serovar Albany from food and feces of wild captive carnivores in a zoo from northwestern Mexico. This serovar was also associated with the death of an ocelot (Leopardus pardalis) in the same zoo. Another group associated S. Albany with the death of a human patient. It is due to this zoonotic potential that the in vivo study of the host-S. Albany relationship is critical. The recombinant S. Albany-Ovalbumin (rSAO) strain was used to analyze a murine oral infection and its specific cytotoxic T lymphocyte (CTL) response. Our results have shown for the first time that rSAO establishes a systemic infection and evokes epitope-specific lysis with a Th1-like cytokine profile in vivo.

Preclinical Evaluation of Invariant Natural Killer T Cells Modified with CD38 or BCMA Chimeric Antigen Receptors for Multiple Myeloma.

Due to the CD1d restricted recognition of altered glycolipids, Vα24-invariant natural killer T (iNKT) cells are excellent tools for cancer immunotherapy with a significantly reduced risk for graft-versus-host disease when applied as off-the shelf-therapeutics across Human Leukocyte Antigen (HLA) barriers. To maximally harness their therapeutic potential for multiple myeloma (MM) treatment, we here armed iNKT cells with chimeric antigen receptors (CAR) directed against the MM-associated antigen CD38 and the plasma cell specific B cell maturation antigen (BCMA). We demonstrate that both CD38- and BCMA-CAR iNKT cells effectively eliminated MM cells in a CAR-dependent manner, without losing their T cell receptor (TCR)-mediated cytotoxic activity. Importantly, iNKT cells expressing either BCMA-CARs or affinity-optimized CD38-CARs spared normal hematopoietic cells and displayed a Th1-like cytokine profile, indicating their therapeutic utility. While the costimulatory domain of CD38-CARs had no influence on the cytotoxic functions of iNKT cells, CARs containing the 4-1BB domain showed a better expansion capacity. Interestingly, when stimulated only via CD1d+ dendritic cells (DCs) loaded with α-galactosylceramide (α-GalCer), both CD38- and BCMA-CAR iNKT cells expanded well, without losing their CAR- or TCR-dependent cytotoxic activities. This suggests the possibility of developing an off-the-shelf therapy with CAR iNKT cells, which might even be boostable in vivo by administration α-GalCer pulsed DCs.

Transient redirection of T cells for adoptive cell therapy with telomerase-specific T helper cell receptors isolated from long term survivors after cancer vaccination

ABSTRACTAdoptive cell therapy (ACT) with retargeted T cells has produced remarkable clinical responses against cancer, but also serious toxicity. Telomerase is overexpressed in most cancers, but also expressed in some normal cells, raising safety concerns. We hypothesize that ACT with T-helper cell receptors may overcome tumour tolerance, mobilize host immune cells and induce epitope spreading, with limited toxicity. From long term survivors after cancer vaccination, we have isolated telomerase-specific T cell receptors (TCRs) from T-helper cells. Herein, we report the development of transient retargeting of T cells with mRNA-based TCRs. This strategy allows for safer clinical testing and meaningful dose escalation. DP4 is the most common HLA molecule. We cloned two telomerase-specific, DP4-restricted TCRs into the mRNA expression vector pCIpA102, together with the sorter/marker/suicide gene RQR8. Donor T cells were electroporated with mRNA encoding TCR_RQR8. The results showed that both TCR_RQR8 constructs were expressed in >90% of T cells. The transfected T cells specifically recognized the relevant peptide, as well as naturally processed epitopes from a 177aa telomerase protein fragment, and remained functional for six days. A polyfunctional and Th1-like cytokine profile was observed. The TCRs were functional in both CD4+and CD8+recipient T cells, even though DP4-restricted. The findings demonstrate that the cloned TCRs confer recipient T cells with the desired telomerase-specificity and functionality. Preclinical experiments may provide limited information on the efficacy and toxicity of T-helper TCRs, as these mobilize the host immune system. We therefore intend to use the mRNA-based TCRs for a first-in-man trial.

The neonatal anti-viral response fails to control measles virus spread in neurons despite interferon-gamma expression and a Th1-like cytokine profile

Neonates are highly susceptible to viral infections in the periphery, potentially due to deviant cytokine responses. Here, we investigated the role of interferon-gamma (IFNγ), a key anti-viral in the neonatal brain. We found that (i) IFNγ, which is critical for viral control and survival in adults, delays mortality in neonates, (ii) IFNγ limits infiltration of macrophages, neutrophils, and T cells in the neonatal brain, (iii) neonates and adults differentially express pathogen recognition receptors and Type I interferons in response to the infection, (iv) both neonates and adults express IFNγ and other Th1-related factors, but expression of many cytokines/chemokines and IFNγ-responsive genes is age-dependent, and (v) administration of IFNγ extends survival and reduces CD4 T cell infiltration in the neonatal brain. Our findings suggest age-dependent expression of cytokine/chemokine profiles in the brain and distinct dynamic interplays between lymphocyte populations and cytokines/chemokines in MV-infected neonates.

Chain length-dependent effects of inulin-type fructan dietary fiber on human systemic immune responses against hepatitis-B.

In vivo studies demonstrating that only specific dietary-fibers contribute to immunity are still inconclusive, as measuring immune effects in healthy humans remains difficult. We applied a relatively inefficacious vaccination-challenge to study chain length-dependent effects of inulin-type fructan (ITF) dietary fibers on human immunity. ITFs with two different 'degree of polymerization-' (DP)-profiles were tested in vitro for effects on PBMC-cytokines and TLR2 activation. In a double-blind placebo-controlled trial, 40 healthy volunteers (18-29 years) were divided into three groups and supplemented from day 1 to day 14 with DP10-60 ITF, DP2-25 ITF (both n = 13), or fructose placebo (n = 14), 8 g/day. On day 7, all volunteers were vaccinated against hepatitis B. Anti-HbsAg-titer development and lymphocyte subsets were studied. In vitro, DP10-60 ITFs stimulated a Th1-like cytokine profile and stimulated TLR2 more strongly than DP2-25 ITFs. In vivo, DP10-60 increased anti-HBsAg titers, Th1-cells, and transitional B-cells. Both ITFs increased CD45ROhi CTLs at day 35, and CD161+ cytokine producing NK-cells at day 21 and 35. Support of immunity is determined by the chain length of ITFs. Only long-chain ITFs support immunity against pathogenic hepB-epitopes introduced by vaccination. Our findings demonstrate that specific dietary fibers need to be selected for immunity support.

Altered Invariant Natural Killer T cell Subsets and its Functions in Patients with Oral Squamous Cell Carcinoma

Invariant natural killer T (iNKT) cells are glycolipid-reactive T lymphocytes that share receptors and function with natural killer (NK) cells and reportedly play a pivotal role in various immune responses. However, iNKT cells are not well characterized in patients with oral squamous cell carcinoma (OSCC). We investigated the populations and functions of circulating iNKT (CD3(+) 6B11(+) ) cells from thirty-eight patients with OSCC and twenty-eight healthy donors by flow cytometry. Circulating iNKT cells were significantly lower (P < 0.01) in patients as compared to those in healthy controls. Further, iNKT subsets revealed a marked decrease in CD4(-) CD8(-) (double negative, DN) subset with concomitant increase in CD8(+) subset in patients as compared to healthy controls (P = 0.03 and P < 0.01, respectively), whereas CD4(+) subset was similarly distributed in both groups. The functional analysis demonstrated that residual iNKT cells from patients had impaired proliferative response to α-galactosylceramide (α-GalCer)-pulsed dendritic cells (DCs) and Th2-like cytokine profile. However, in vitro activation with α-GalCer-pulsed DCs restores IFN-γ expression and enhances antitumour activity to human cancer cells lines (SCC-4, KB and MCF7). It appears that the selectively enriched iNKT subsets and modulation of their function by specific ligand/agonist may be useful for cellular therapy in patients with OSCC. Further, reduced levels of iNKT cells and its DN subset may be used as potential prognostic factors for patients with OSCC.

NOD2 activity modulates the phenotype of LPS-stimulated dendritic cells to promote the development of T-helper type 2-like lymphocytes — Possible implications for NOD2-associated Crohn's disease

Sensing of commensal microorganisms via Toll-like receptors (TLR) in the gut is essential for maintaining intestinal homeostasis in healthy individuals. Conversely, Crohn's disease is characterised by an inappropriate T helper-type 1 (Th1)-mediated immune response towards these same microorganisms. NOD2 is expressed by dendritic cells (DC) and mediates responses to bacterial muramyl-dipeptides (MDP). Mutations in NOD2 (CARD15) have recently been associated with susceptibility to Crohn's disease although the underlying mechanisms have yet to be established. We investigated the functional outcome of NOD2 and TLR4-mediated activation in monocyte-derived DC from wild-type NOD2 healthy controls and NOD2 frame-shift mutation-carrying Crohn's disease patients. In wild-type DC, MDP acted synergistically with LPS to amplify inflammatory cytokine production, enhance co-stimulatory molecule expression, and produce DC that promoted the proliferation of naïve, allogeneic, CD4+ T lymphocytes with a Th2-like cytokine profile. By contrast, DC carrying homozygous NOD2 mutations were unable to react to MDP, responded to LPS only, and promoted the development of Th1 cells. These results suggest activation of the NOD2 pathway in DC modulates their response to TLR agonists and regulates their ability to induce polarised Th1 responses. As a consequence, Crohn's disease patients with defective NOD2 may be predisposed to the generation of strongly polarised Th1 responses against common commensal microorganisms.

Regulatory T Lymphocytes: Pivotal Components of the Host Antitumor Response

The role of host immunity in the development and progression of cancer has been a subject of speculation and considerable controversy for more than the last 50 years. Tumor-infiltrating lymphocytes (TILs), the primary immune component infiltrating solid tumors, are considered to be a manifestation of the host antitumor reaction. The report by Gao et al in this issue provides additional evidence for the prognostic significance of TILs in solid tumors in general and hepatocellular carcinoma (HCC) specifically. Historically, tumor-associated lymphoid infiltrates were categorized descriptively as brisk, nonbrisk, or absent, based on morphologic observation alone. The survival advantage of a brisk lymphocytic infiltrate in malignant melanoma has been demonstrated by Clark et al, and confirmed by others. However, there is accumulating evidence that the specific type of immune cells, rather than their sheer quantity, governs the host-versus-tumor immune response. With development of immunohistochemical and flow cytometry techniques, it has been demonstrated that the majority of TILs in solid tumors are of the CD3 T-cell phenotype. CD3 T cells can be stratified further into CD4 helper cells (including the Th1 and Th2 subtypes based on their cytokine profile), CD4 regulatory T cells (Tregs), previously designated as suppressor cells, and CD8 cytotoxic effector cells. Initial studies that set out to characterize the antitumor immune response were directed toward CD8 cytotoxic T lymphocytes (CTLs). CTLs destroy tumor cells via the triggering of apoptosis by means of cytotoxic granule exocytosis and/or the Fas/FasL receptor–mediated pathway. In the mid-1990s, antibodies that recognize cytotoxic molecules, including TIA-1, granzyme B, and perforin, became available for immunohistochemical studies. The number of CD8 CTLs expressing TIA-1 and/or granzyme B cytotoxic granules infiltrating tumors has been shown to be associated with improved prognosis in certain human neoplasms, such as Epstein-Barr virus–associated gastric cancer and carcinomas of the colon, breast, uterus, and esophagus. The role of CD4 T cells in the host antitumor response is an area of considerable debate. This subset may be considered as a double-edged immunologic sword, able to promote or inhibit tumor growth. CD4 T-helper cells are subdivided into Th1 cells, which induce cellular immunity, and Th2 cells, which elicit a humoral immune response. The Th1 response is associated with CTL activation and is considered to be beneficial for antitumor immunity. In contrast, a predominant Th2-like cytokine profile is associated with a metastasis-inclined microenvironment in HCC and other tumors. A subpopulation of CD4 T cells, Tregs, which accounts for 5% to 10% of all CD4 cells, is generating intense interest in tumor immunology, autoimmunity, and infectious disease. Historically, Tregs were first hypothesized as suppressive T cells in early 1971 by Gershon and Kondo, however, subsequent studies were hindered because of a lack of specific molecular markers and difficulties in their isolation and culture. The renaissance of these regulatory cells came a few years ago, when FOXP3, a member of the forkhead family of DNA transcription factors, was cloned. There is now considerable evidence that FOXP3 is a key control molecule for Treg development and function, and is an excellent marker for the study of Tregs. Recent studies have demonstrated that Tregs are beneficial for the prevention of autoimmune disease, such as type I diabetes, graft-versus-host disease, transplant rejection, and tissue destruction during infection. In contrast, Tregs seem to be a detrimental factor in the generation of host-versus-tumor immunity via suppression of tumorspecific effector T-cell responses and development of immune tolerance to neoplastic cells. The classic Treg is a thymus-derived CD4 CD25 FOXP3 T lymphocyte. In addition to these markers, Tregs express cell surface CTL-associated antigen 4 (CTLA-4), and the glucocorticoidinduced tumor necrosis factor alpha receptor and secrete immunosuppressive cytokines such as transforming growth factor beta and interleukin 10 (IL-10). Initially it was demonstrated that the number of CD4 CD25 T-cells were increased in several solid tumors and in certain hematologic malignancies. However, subsequent studies provided evidence that CD25, which is an IL-2 receptor subunit, is induced on activation in all T-cells, not just Tregs. Recently, there has been an sudden increase of immunohistochemical studies using FOXP3 as a more specific marker of Tregs. Increased numbers of FOXP3 Tregs infiltrating tumor cell nests have been demonstrated in ovarian, lung, breast, pancreatic, hepatocellular, head and neck, and anal carcinomas, and lymphomas. In most of the solid tumors studied, accumulation of FOXP3 Tregs predicts a striking reduction of patient survival; however, paradoxically, increased FOXP3 Tregs were found to be associated with improved prognosis in lymphoma patients. JOURNAL OF CLINICAL ONCOLOGY E D I T O R I A L VOLUME 25 NUMBER 18 JUNE 2

Treatment of Adenovirus Infection by Adoptive Immunotherapy: Adenovirus Capsid Hexon Is the Main Target Protein of Adenovirus-Specific Cellular Immunity.

Introduction: Adenovirus (AdV) infection is a severe complication after hematopoietic stem cell transplantation, particularly in paediatric patients. Control of AdV infection particularly seems to be dependent on CD4+ T-cells but their main AdV antigenic targets have remained unknown so far. In order to design protocols for targeted adoptive immunotherapy the identification of the main AdV antigenic targets is a fundamental prerequisite.Methods: We here adapted a novel technique to directly assess the entire repertoire of CD4+ T-cells specific AdV antigens according to antigen-induced CD154 expression after short-term ex vivo stimulation. AdV-lysate-specific and AdV-hexon-specific CD4+ T-cells were isolated, expanded in vitro and further assessed for their fine specificities using recombinant AdV-proteins and AdV-lysates from various AdV-serogroups. The cytokine profile of AdV-lysate- and AdV-hexon-specific CD4+ T-cells were assessed by intracellular analysis of AdV-induced CD154+ CD4+ T-cells.Results: AdV-lysate-specific CD4+ T-cells reacted predominantly with AdV-hexon capsid protein. Furthermore, AdV-hexon (serogroup B) specific CD4+ T-cells crossreacted with recombinant hexon protein derived from various other AdV-serotypes and were characterized by a Th1-like cytokine profile.Conclusion: Our results prove the effectiveness of antigen-induced CD154-expression for assessment of the entire repertoire of CD4+ T-cells specific for pathogens, for the identification of immunodominant target antigen from pathogens. We demonstrate that adenovirus hexon protein is a suitable candidate antigen for the ex vivo generation of adenovirus-specific, serogroup cross-reactive CD4+ T-cells with a Th1-like cytokine profile for adoptive T-cell therapies.

Interleukin-10 and tumor necrosis factor-alpha: model of immunomodulation in multiple sclerosis

Objectives: The mechanisms involved in the pathogenesis of relapsing-remitting multiple sclerosis are still unclear. The aim of the present study was to evaluate both cerebrospinal fluid (CSF) CD4+ CD7+ T cells and peripheral blood (PB) interleukin-10 (IL-10) as well as tumor necrosis-alpha (TNF-α) levels in patients with definite multiple sclerosis of the relapsing-remitting type.Methods: To assess the above-mentioned cytokine levels we performed our test by the means of ELI-spot assay; the T-helper cell subset was assayed using flow cytometry.Results: PB IL-10 levels of multiple sclerosis (MS) patients in remission were significantly (p<0.001) higher than in MS patients in the active phase. There was significant and increased evidence of TNF-α levels only in the MS patients in the active phase. CD4+ CD7+ T cells, characterized by a preferential Th1-like cytokine profile, were detectable only in seven patients in the active phase without evidence of a statistical significance with respect to cytokine levels.Conclusion: The data indicate that the production of different cytokines characterized the expression of relapsing-remitting MS. The data also suggest that is it possible to control MS using the regulatory cytokine balance.

T Cell Receptor Gene Usage in Desmoglein-3-Specific T Lymphocytes from Patients with Pemphigus Vulgaris

Pemphigus vulgaris (PV) is an autoimmune disease mediated by autoantibodies against desmoglein-3 (Dsg3). It has been documented that both humoral and cellular autoimmunity play essential roles in the development of PV. Recently, we identified that T cells from PV patients respond to three antigenic fragments on the ectodomain of Dsg3. These T cells are CD4 alpha/beta cells secreting a Th2-like cytokine profile, and responding of Dsg3 in a restriction to HLA-DRBI*0402 or 1401 alleles. Other characteristics of these cells, such as detailed epitope(s) and T cell receptors (TCRs) usage, however, have not been investigated. The purpose of this study is to determine detailed T cell epitope(s) and TCR genes utilized by Dsg3-specific T cells. Here, we found that Dsg3(AA145-192)-specific cells preferentially utilize the TCRVbeta13 gene, while Dsg3(AA240-303)- and Dsg3 (AA570-614)-specific cells utilize Vbeta7 and Vbeta17 genes, respectively. Analysis of TCRValpha gene expression, it appears that Valpha22 gene is expressed by Dsg3(AA145-192)-specific cells, whereas the Valpha10 gene is predominantly utilized by Dsg3(AA240-303)-specific T cells. There are no specific utilization of Valpha gene in the group of cells proliferate to Dsg3 (AA570-614). We believe that this information will further our understanding of the properties of autoimmune T cells in patients with PV.

Leishmania mexicana H-line attenuated under pressure of gentamicin, potentiates a Th1 response and control of cutaneous leishmaniasis in BALB/c mice.

An attenuated line of Leishmania mexicana (the L. mexicana H-line) has been established by culturing in vitro under gentamicin pressure. BALB/c mice infected with the L. mexicana H-line developed a CD4(+)Th1-like response, indicated by the cytokine profile of their splenocytes stimulated by L. mexicana wild-type (WT) promastigotes. This profile is sustained after these mice are challenged with L. mexicana WT. Control mice infected with L. mexicana WT alone developed a CD4(+)Th2-like cytokine profile. In mice immunized with L. mexicana H-line and then challenged with WT-line, were eliminated when immunizing H-line parasites persisted in the skin and draining popliteal lymph nodes (PLNs). In experiments in which mice were inoculated with attenuated and WT parasites at the same time, either at the same site or on separate sides of the mouse, growth of the WT parasites was significantly contained and controlled, indicating a possible therapeutic role for the attenuated parasites.

Identification of a mutated receptor-like protein tyrosine phosphatase kappa as a novel, class II HLA-restricted melanoma antigen.

Recent studies increasingly point to a pivotal role of CD4(+) T cells in human anti-tumor immune response. Here we show that lymphocytes purified from a tumor-infiltrated lymph node of a melanoma patient that had remained disease free for 10 years after surgical resection of a lymph node metastasis comprised oligoclonal class II HLA-restricted CD4(+) T cells recognizing the autologous tumor cells in vitro. In fact, the CD4(+) T cell clones isolated from these lymphocytes displayed a tumor-specific, cytotoxic activity in addition to a Th1-like cytokine profile. By a genetic approach, a peptide derived from a mutated receptor-like protein tyrosine phosphatase kappa was identified as a novel HLA-DR10-restricted epitope for all the melanoma-specific CD4(+) T cell clones. The immunogenic peptide was shown to contain the mutated residue that was crucial for T cell recognition and activation. Moreover, a systemic immunity against the mutated peptide was detectable in the patient's peripheral blood T lymphocytes obtained during the disease-free period of follow-up. These findings further support the relevance of CD4(+) T cells directed against mutated epitopes in tumor immunity and provide the rationale for a possible usage of mutated, tumor-specific Ags for immunotherapy of human cancer.

A humanized model of experimental autoimmune uveitis in HLA class II transgenic mice.

Experimental autoimmune uveitis (EAU) is a disease of the neural retina induced by immunization with retinal antigens, such as interphotoreceptor retinoid-binding protein (IRBP) and arrestin (retinal soluble antigen, S-Ag). EAU serves as a model for human autoimmune uveitic diseases associated with major histocompatibility complex (HLA) genes, in which patients exhibit immunological responses to retinal antigens. Here we report the development of a humanized EAU model in HLA transgenic (TG) mice. HLA-DR3, -DR4, -DQ6, and -DQ8 TG mice were susceptible to IRBP-induced EAU. Importantly, HLA-DR3 TG mice developed severe EAU with S-Ag, to which wild-type mice are highly resistant. Lymphocyte proliferation was blocked by anti-HLA antibodies, confirming that antigen is functionally presented by the human MHC molecules. Disease could be transferred by immune cells with a Th1-like cytokine profile. Antigen-specific T cell repertoire, as manifested by responses to overlapping peptides derived from S-Ag or IRBP, differed from that of wild-type mice. Interestingly, DR3 TG mice, but not wild-type mice, recognized an immunodominant S-Ag epitope between residues 291 and 310 that overlaps with a region of S-Ag recognized by uveitis patients. Thus, EAU in HLA TG mice offers a new model of uveitis that should represent human disease more faithfully than currently existing models.

A humanized model of experimental autoimmune uveitis in HLA class II transgenic mice

Experimental autoimmune uveitis (EAU) is a disease of the neural retina induced by immunization with retinal antigens, such as interphotoreceptor retinoid-binding protein (IRBP) and arrestin (retinal soluble antigen, S-Ag). EAU serves as a model for human autoimmune uveitic diseases associated with major histocompatibility complex (HLA) genes, in which patients exhibit immunological responses to retinal antigens. Here we report the development of a humanized EAU model in HLA transgenic (TG) mice. HLA-DR3, -DR4, -DQ6, and -DQ8 TG mice were susceptible to IRBP-induced EAU. Importantly, HLA-DR3 TG mice developed severe EAU with S-Ag, to which wild-type mice are highly resistant. Lymphocyte proliferation was blocked by anti-HLA antibodies, confirming that antigen is functionally presented by the human MHC molecules. Disease could be transferred by immune cells with a Th1-like cytokine profile. Antigen-specific T cell repertoire, as manifested by responses to overlapping peptides derived from S-Ag or IRBP, differed from that of wild-type mice. Interestingly, DR3 TG mice, but not wild-type mice, recognized an immunodominant S-Ag epitope between residues 291 and 310 that overlaps with a region of S-Ag recognized by uveitis patients. Thus, EAU in HLA TG mice offers a new model of uveitis that should represent human disease more faithfully than currently existing models.

Molecular analysis of resolving immune responses in uveitis.

To identify the cellular immune processes underlying intra-ocular inflammation, aqueous humour was obtained at cataract surgery from 22 patients with clinically inactive uveitis and 24 patients with age-related cataract. mRNA expression for the cytokines IL-1beta, IL-2, IL-4, IL-6, IL-10, IL-12, interferon-gamma (IFN-gamma), transforming growth factor-beta (TGF-beta); T cell subsets CD3, CD4, CD8; monocytes and macrophages (CD14); and B cells (CD19) was measured using reverse transcriptase-polymerase chain reaction (RT-PCR) and radiometric analysis. The majority of uveitis patients demonstrated a T cell-mediated inflammatory response, predominately involving a Th1-like cytokine profile with expression of IL-2 and IFN-gamma in 16/22 and 18/22 samples, respectively. These cytokines were present in only a small number of patients with age-related cataract. This Th1-like polarization was supported by an increased expression of CD8 in a number of patients. IL-1beta was expressed in only six uveitic eyes. Only four patients expressed either IL-4 or IL-10 and no patient expressed both. TGF-beta mRNA could be detected in 18/22 uveitis patients and 15/24 controls. IL-12, the paradigmatic Th1-inducing cytokine, was absent in all samples but CD14 was expressed in the majority of patients and controls. CD19 could not be detected in any sample. The cellular infiltrate in the uveitic eyes showed clear evidence of low IL-1 and absent IL-12 expression despite a Th1-like profile and high expression of macrophages. This strongly suggests that the systemic immunosuppressive therapy used prior to surgery in some patients and/or the chronicity of the uveitis had actively suppressed/switched off macrophage function, leading to resolution of T cell activity.

γδ T Cells Express Activation Markers in the Central Nervous System of Mice with Chronic-relapsing Experimental Autoimmune Encephalomyelitis

In this study, we assessed the expression of activation markers on γδ T cells in central nervous system (CNS) lesions of SJL mice adoptively sensitized to develop experimental autoimmune encephalomyelitis (EAE) using myelin basic protein-reactive T cells. Although disease expression is known to be dependent upon T cells that express the αβ T cell receptor (TCR), a role for γδ T cells has been implicated in some studies but not in others. Using three-color flow cytometric analysis of both total and γδ T cells in spleen and CNS, the data showed that expression of CD69 (early activation marker), CD62L (lymphocyte homing receptor), CD25 (IL-2Rα), CD122 (IL-2Rβ) and CD95/CD95L (Fas/FasL), fluctuated on γδ T cells in EAE lesions in a disease-related fashion. Furthermore, the pattern of expression for these markers on γδ T cells was distinct from that found on the total lymphocyte population. Cytokine analysis of γδ T cells in the CNS demonstrated a bias towards a Th1-like cytokine profile. From these data, we conclude that γδ T cells in EAE lesions display an activated phenotype and form a dynamic component of the total lymphocyte population in the CNS, supporting a contributory role for these cells.

Bacterial infections and atopic dermatitis.

Bacterial infections and atopic dermatitis.

A glutamic acid decarboxylase 65-specific Th2 cell clone immunoregulates autoimmune diabetes in nonobese diabetic mice.

Several studies have provided indirect evidence in support of a role for beta cell-specific Th2 cells in regulating insulin-dependent diabetes (IDDM). Whether a homogeneous population of Th2 cells having a defined beta cell Ag specificity can prevent or suppress autoimmune diabetes is still unclear. In fact, recent studies have demonstrated that beta cell-specific Th2 cell clones can induce IDDM. In this study we have established Th cell clones specific for glutamic acid decarboxylase 65 (GAD65), a known beta cell autoantigen, from young unimmunized nonobese diabetic (NOD) mice. Adoptive transfer of a GAD65-specific Th2 cell clone (characterized by the secretion of IL-4, IL-5, and IL-10, but not IFN-gamma or TGF-beta) into 2- or 12-wk-old NOD female recipients prevented the progression of insulitis and subsequent development of overt IDDM. This prevention was marked by the establishment of a Th2-like cytokine profile in response to a panel of beta cell autoantigens in cultures established from the spleen and pancreatic lymph nodes of recipient mice. The immunoregulatory function of a given Th cell clone was dependent on the relative levels of IFN-gamma vs IL-4 and IL-10 secreted. These results provide direct evidence that beta cell-specific Th2 cells can indeed prevent and suppress autoimmune diabetes in NOD mice.

Age-related changes in cytokine production by leukocytes in rhesus monkeys.

Using a variety of experimental rodent and human models, age-related alterations in cytokine production by immune cells have been described extensively. While the precise mechanism(s) responsible for such age-related changes in cytokine responses remain unclear, it seems likely that these changes may have a significant effect on immune cell function. In an attempt to clarify such changes in aging primates, we examined cytokine production by white cells derived from a controlled colony of rhesus monkeys (Macaca mulatta). Non-fractionated whole blood and peripheral blood mononuclear cells (PBMCs) were obtained from male monkeys of different ages (6-28 years), and were subsequently evaluated for their ability to express mRNA and protein for the cytokines, IL-10, IL-6, IFNgamma, IL-1beta, and TNFalpha, following in vitro stimulation with polyclonal mitogens. Our results suggest that white blood cells derived from aged rhesus monkeys exhibit a significant increase in their ability to produce the Th2-associated cytokine, IL-10, upon stimulation with lipopolysaccharide (LPS) when compared to white cells derived from younger counterparts. Similarly, a significant age-related decrease in the expression of the Th1-associated cytokine, IFNgamma, was also observed using phytohemagglutinin (PHA)-stimulated PBMCs. No significant age-related differences in the production of IL-1beta or TNFalpha were observed in response to any stimulation, but there was limited evidence of an age-related increase in IL-6 production. Overall, our results suggest that a possible systemic change from a Th0/Th1 to a Th2-like cytokine profile occurs in circulating leukocytes derived from aging primates. We believe that such age-related alterations in cytokine production may play a role in the reduced immune responses observed in elderly human populations.