Gene expression induced by interleukin-17 in fibroblast-like synoviocytes of patients with rheumatoid arthritis: upregulation of hyaluronan-binding protein TSG-6

Interleukin-17 (IL-17) has been characterized as a proinflammatory cytokine produced by CD4(+ )CD45RO(+ )memory T cells. Overproduction of IL-17 was detected in the synovium of patients with rheumatoid arthritis (RA) compared with patients with osteoarthritis. This study examines differentially expressed genes after the stimulation of fibroblast-like synoviocytes of RA patients by IL-17. Among these genes we identified the following: tumor necrosis factor-stimulated gene-6 (TSG-6), IL-6, IL-8, GRO-β, and bone morphogenetic protein-6 with an expression 3.6–10.6-fold that in the unstimulated control. IL-17 augmented the expression of TSG-6, a hyaluronan-binding protein, in a time- and dose-dependent manner. IL-17 showed additive effects with IL-1β and tumour necrosis factor-α on the expression of TSG-6, IL-6 and IL-8. The mitogen-activated protein kinase p38 seems to be necessary for the regulation of TSG-6 expression by IL-17, as shown by inhibition with SB203580. Our results support the hypothesis that IL-17 is important in the pathogenesis of RA, contributing to an unbalanced production of cytokines as well as participating in connective tissue remodeling

In-vivo-Effekte proliferationsbasierter T-Zellselektion bei allogener Knochenmarktransplantation in murinen Systemen

Für maligne Erkrankungen des hämatopoetischen Systems stellt die allogene Knochenmarktransplantation ein gut etabliertes Therapieverfahren dar. Der kurative Effekt einer solchen Behandlung liegt in der Erkennung und Zerstörung maligner Zellen durch im Transplantat enthaltene immunkompetente Zellen (Graft-versus-Leukämie (GvL)-Effekt). Hauptnebenwirkung der Knochenmarktransplantation stellt die Graft-versus-host Erkrankung (GvHD) dar, eine Immunreaktion der transplantierten Zellen gegen Empfängergewebe. Diese kann einen schweren bis tödlichen Verlauf nehmen. Im Rahmen dieser Arbeit wurde ein neues Verfahren geprüft, T-Zellen in vitro aufgrund von Proliferationsunterschieden gegenüber allogenen Stimuli zu trennen. Die Separation erfolgte mittels einer Farbstoffverdünnungsmethode („CFSE“) und anschließender FACS-Sortierung. Zytotoxizitätsmessungen zeigen, dass in vitro proliferierende Zellen („low“) im Gegensatz zur ruhenden Zellfraktion („high“) zytolytische Aktivität gegenüber Rezipientenzellen zeigen. Im Kontext allogener Knochen-marktransplantation im Mausmodell wurden die in vivo-Effekte der erhaltenen T-Zellpopulationen untersucht. Im Gegensatz zu alloreaktiven T-Zellen („low“) induzieren in vitro ruhende Zellen in zwei unterschiedlichen Transplantationsmodellen keine GvHD. Eine verbleibende Reaktivität der „high“-Zellen gegenüber unverwandten Antigenen konnte nach Reisolation demonstriert werden. Jedoch vermitteln die transplantierten „high“-Zellen – im MHC-identen Modellsystem – keine Tumorabstoßung (Verlust des GvL-Effektes). Die Gewinnung tumorreaktiver T-Zellen mittels dieses Separationsverfahrens und deren Transplantation scheinen jedoch erfolgversprechend, da durch Transfer dieser T-Zellen die Induktion einer GvHD vermieden werden kann, bei erwiesener Tumorreaktivität

Cytomegalovirus drives Vδ2neg γδ T cell inflation in many healthy virus carriers with increasing age

Cytomegalovirus (CMV) usually causes lifelong asymptomatic infection, but over time can distort immune profiles. Recent reports describe selective expansion of Vδ2(neg) γδ T cells in healthy and immunocompromised CMV carriers. Having shown previously that virus-specific CD8(+) and CD4(+) T cell responses are increased significantly in elderly CMV carriers, probably driven by chronic stimulation, we hypothesized that Vδ2(neg) γδ T cells may also be expanded with age. Our results show that Vδ2(neg) γδ T cells are increased significantly in CMV-seropositive healthy individuals compared to CMV-seronegative controls in all age groups. The differences were most significant in older age groups (P < 0·0001). Furthermore, while Vδ2(neg) γδ T- cells comprise both naive and memory cells in CMV-seronegative donors, highly differentiated effector memory cells are the dominant phenotype in CMV carriers, with naive cells reduced significantly in numbers in CMV-seropositive elderly. Although phenotypically resembling conventional CMV-specific T cells, Vδ2(neg) γδ T cells do not correlate with changes in magnitude of CMV-specific CD4(+) or CD8(+) T cell frequencies within those individuals, and do not possess ex-vivo immediate effector function as shown by CMV-specific CD4(+) and CD8(+) T cells. However, after short-term culture, Vδ2(neg) γδ T cells demonstrate effector T cell functions, suggesting additional requirements for activation. In summary, Vδ2(neg) γδ T cells are expanded in many older CMV carriers, demonstrating a further level of lymphocyte subset skewing by CMV in healthy individuals. As others have reported shared reactivity of Vδ2(neg) γδ T cells towards tumour cells, the composition of γδ T cell subsets may also have implications for risk of developing cancer in elderly people

Acyclovir therapy reduces the CD4+ T cell response against the immunodominant pp65 protein from cytomegalovirus in immune competent individuals

Cytomegalovirus (CMV) infects the majority of the global population and leads to the development of a strong virus-specific immune response. The CMV-specific CD4+ and CD8+ T cell immune response can comprise between 10 and 50% of the T cell pool within peripheral blood and there is concern that this may impair immunity to other pathogens. Elderly individuals with the highest magnitude of CMV-specific immune response have been demonstrated to be at increased risk of mortality and there is increasing interest in interventions that may serve to moderate this. Acyclovir is an anti-viral drug with activity against a range of herpes viruses and is used as long term treatment to suppress reactivation of herpes simplex virus. We studied the immune response to CMV in patients who were taking acyclovir to assess if therapy could be used to suppress the CMV-specific immune response. The T cell reactivity against the immunodominant late viral protein pp65 was reduced by 53% in people who were taking acyclovir. This effect was seen within one year of therapy and was observed primarily within the CD4+ response. Acyclovir treatment only modestly influenced the immune response to the IE-1 target protein. These data show that low dose acyclovir treatment has the potential to modulate components of the T cell response to CMV antigen proteins and indicate that anti-viral drugs should be further investigated as a means to reduce the magnitude of CMV-specific immune response and potentially improve overall immune function

The cellular localization of human cytomegalovirus glycoprotein expression greatly influences the frequency and functional phenotype of specific CD4+ T cell responses

CMV infection is a significant cause of morbidity and mortality in immunocompromised individuals, and the development of a vaccine is of high priority. Glycoprotein B (gB) is a leading vaccine candidate but the glycoprotein H (gH) pentameric complex is now recognized as the major target for neutralizing Abs. However, little is known about the T cell immune response against gH and glycoprotein L (gL) and this is likely to be an important attribute for vaccine immunogenicity. In this study, we examine and contrast the magnitude and phenotype of the T cell immune response against gB, gH, and gL within healthy donors. gB-specific CD4(+) T cells were found in 95% of donors, and 29 epitopes were defined with gB-specific response sizes ranging from 0.02 to 2.88% of the CD4(+) T cell pool. In contrast, only 20% of donors exhibited a T cell response against gH or gL. Additionally, gB-specific CD4(+) T cells exhibited a more cytotoxic phenotype, with high levels of granzyme B expression. Glycoproteins were effectively presented following delivery to APCs but only gB-derived epitopes were presented following endogenous synthesis. gB expression was observed exclusively within vesicular structures colocalizing with HLA-DM whereas gH was distributed evenly throughout the cytoplasm. Grafting of the C-terminal domain from gB onto gH could not transfer this pattern of presentation. These results reveal that gB is a uniquely immunogenic CMV glycoprotein and this is likely to reflect its unique pattern of endogenous Ag presentation. Consideration may be required toward mechanisms that boost cellular immunity to gH and gL within future subunit vaccines

Cytokine production and antigen recognition by human mucosal homing conjunctival effector memory CD8+ T cells

PURPOSE. Conjunctival epithelial T cells are dominated by CD3(+)CD56-TCRαβ(+)CD8αβ(+) lymphocytes. In this study we explored the antigen experience status, mucosal homing phenotype, cytokine expression, and viral antigen recognition of conjunctival epithelial CD8(+) T cells from healthy individuals. METHODS. Following ocular surface impression cytology, conjunctival cells were recovered by gentle agitation and analyzed by flow cytometry for cell surface markers, cytokine production (stimulated by phorbol 12-myristate 13-acetate [PMA]/ionomycin), and Epstein-Barr virus (EBV)/cytomegalovirus (CMV) immunodominant epitope recognition using major histocompatibility complex (MHC) class I peptide tetramers. RESULTS. In contrast to peripheral blood, conjunctival epithelial CD8(+) T cells were dominantly CD45RA(−)CCR7(−) effector memory cells, and the vast majority expressed the mucosal homing integrin αEβ7. Conjunctival memory CD8(+) T cells maintained effector functions with the ability to secrete IFN-γ and expression of Granzyme B, although they expressed significantly reduced amounts per cell compared to peripheral blood T cells. Interestingly, herpetic virus-specific CD8(+) T cells recognizing epitopes derived from EBV and CMV could be detected in the conjunctival cells of healthy virus carriers, although they were generally at lower frequencies than in the peripheral blood of the same donor. Virus-specific conjunctival CD8(+) T cells were dominated by CD45RA(−)CCR7(−) effector memory cells that expressed αEβ7. CONCLUSIONS. These data demonstrate that the majority of conjunctival epithelial CD8(+) T cells are mucosal homing αEβ7(+) effector memory T cells, which can recognize viral epitopes and are capable of secreting Granzyme B and IFN-γ

Fighting viral infections and virus-driven tumors with cytotoxic CD4+ T cells

CD4+ T cells have been and are still largely regarded as the orchestrators of immune responses, being able to differentiate into distinct T helper cell populations based on differentiation signals, transcription factor expression, cytokine secretion, and specific functions. Nonetheless, a growing body of evidence indicates that CD4+ T cells can also exert a direct effector activity, which depends on intrinsic cytotoxic properties acquired and carried out along with the evolution of several pathogenic infections. The relevant role of CD4+ T cell lytic features in the control of such infectious conditions also leads to their exploitation as a new immunotherapeutic approach. This review aims at summarizing currently available data about functional and therapeutic relevance of cytotoxic CD4+ T cells in the context of viral infections and virus-driven tumors

Defective monocyte enzymatic function and an inhibitory immune phenotype in HIV-exposed uninfected African infants in the era of antiretroviral therapy

BACKGROUND: HIV-Exposed Uninfected (HEU) infants are a rapidly expanding population in sub-Saharan Africa, highly susceptible to encapsulated bacterial disease in the first year of life. The mechanism of this increased risk is still poorly understood. We investigated if HIV-exposure dysregulates HEU immunity, vaccine-antibody production and human herpes virus (HHV) amplify this effect. METHODS: 34 HIV-infected and 44 HIV-uninfected pregnant women were recruited into the birth cohort, followed up to 6 weeks of age; and 43 HIV-infected and 61 HIV-uninfected mother-infant pairs into a longitudinal infant cohort, at either: 5-7 to 14-15; or 14-15 to 18-23 weeks of age. We compared monocyte function, innate and adaptive immune cell phenotype, and vaccine-induced antibody responses between HEU and HU infants. RESULTS: We demonstrate altered monocyte phagosomal function and B cell subset homeostasis, and lower vaccine-induced anti-Haemophilus influenzae type b (Hib) and anti-Tetanus Toxoid (TT) IgG titers in HEU compared to HU infants. HHV infection was similar between HEU and HU infants. CONCLUSION: In the era of antiretroviral therapy (ART)-mediated viral suppression, HIV-exposure may dysregulate monocyte and B cell function, during the vulnerable period of immune maturation. This may contribute to the high rates of invasive bacterial disease and pneumonia in HEU infants

Cytomegalovirus infection does not impact on survival or time to first treatment in patients with chronic lymphocytic leukemia

Human cytomegalovirus (HCMV) is a widely prevalent herpes virus which establishes a state of chronic infection. The establishment of CMV‐specific immunity controls viral reactivation and leads to the accumulation of very large numbers of virus‐specific T cells which come to dominate the immune repertoire. There is concern that this may reduce the immune response to heterologous infections and HCMV infection has been associated with reduced survival in elderly people. Patients with chronic lymphocytic leukemia (B‐CLL) suffer from a state of immune suppression but have a paradoxical increase in the magnitude of the CMV‐specific T cell and humoral immune response. As such, there is now considerable interest in how CMV infection impacts on the clinical outcome of patients with B‐CLL. Utilizing a large prospective cohort of patients with B‐CLL (n = 347) we evaluated the relationship between HCMV seropositivity and patient outcome. HCMV seropositive patients had significantly worse overall survival than HCMV negative patients in univariate analysis (HR = 2.28, 95% CI: 1.34–3.88; P = 0.002). However, CMV seropositive patients were 4 years older than seronegative donors and this survival difference was lost in multivariate modeling adjusted for age and other validated prognostic markers (P = 0.34). No significant difference was found in multivariate modeling between HCMV positive and negative patients in relation to the time to first treatment (HR = 1.12, 95% CI: 0.68–1.84; P = 0.65). These findings in a second independent cohort of 236 B‐CLL patients were validated. In conclusion no evidence that HCMV impacts on the clinical outcome of patients with B‐CLL was found. Am. J. Hematol. 91:776–781, 2016. © 2016 Wiley Periodicals, Inc