The impact of aging on innate and adaptive immunity in the human female genital tract

Mucosal tissues in the human female reproductive tract (FRT) are primary sites for both gynecological cancers and infections by a spectrum of sexually transmitted pathogens, including human immunodeficiency virus (HIV), that compromise women''s health. While the regulation of innate and adaptive immune protection in the FRT by hormonal cyclic changes across the menstrual cycle and pregnancy are being intensely studied, little to nothing is known about the alterations in mucosal immune protection that occur throughout the FRT as women age following menopause. The immune system in the FRT has two key functions: defense against pathogens and reproduction. After menopause, natural reproductive function ends, and therefore, two overlapping processes contribute to alterations in immune protection in aging women: menopause and immunosenescence. The goal of this review is to summarize the multiple immune changes that occur in the FRT with aging, including the impact on the function of epithelial cells, immune cells, and stromal fibroblasts. These studies indicate that major aspects of innate and adaptive immunity in the FRT are compromised in a site‐specific manner in the FRT as women age. Further, at some FRT sites, immunological compensation occurs. Overall, alterations in mucosal immune protection contribute to the increased risk of sexually transmitted infections (STI), urogenital infections, and gynecological cancers. Further studies are essential to provide a foundation for the development of novel therapeutic interventions to restore immune protection and reverse conditions that threaten women''s lives as they age.     

Expressed Salmonella antigens within macrophages enhance the proliferation of CD4+ and CD8+ T lymphocytes by means of bystander dendritic cells

ATP-dependent Lon protease-deficient Salmonella enterica serovar Typhimurium (strain CS2022) appeared to invade successfully the mesenteric lymph nodes (MLN) and Peyer's patches (PP) of BALB/c mice and appeared to be easily eradicated by the host after oral immunization. As detected by flow cytometry, the population of major histocompatibility complex class I (MHC-I)-expressing macrophages and dendritic cells (DCs) was increased in the PP of mice immunized with CS2022 on day 6 after immunization. Thereafter, the population of splenic surface CD69(+) T lymphocytes prepared from mice immunized with CS2022 6 weeks prior to measurement increased as a result of the administration of the extracellular vesicles of RAW264.7 macrophage-like cells derived by Salmonella challenge. In addition, the proliferation of CD8(+) and even of CD4(+)T cells isolated from mouse spleens immunized with CS2022 was enhanced after cocultivation with naive DCs in the presence of the extracellular vesicles. These findings indicate that the extracellular vesicles prepared from the Salmonella-challenged macrophages carried salmonellae antigens to bystander DCs, thereby stimulating T-cell responses. Therefore, as antigen presentation after phagocytosis should be a central process in the T-cell activation that occurs in response to Salmonella infection, an oral immunization with CS2022 sufficiently induces T cell-mediated immunity in mice.     

IL‐12 stimulates the osteoclast inhibitory peptide‐1 (OIP‐1/hSca) gene expression in CD4+ T cells

Immune cell products such as interferon (IFN)‐γ and interleukin (IL)‐12 are potent inhibitors of osteoclast formation. We previously characterized the human osteoclast inhibitory peptide‐1 (OIP‐1/hSca), a Ly‐6 gene family member and showed IFN‐γ modulation of OIP‐1 expression in bone marrow cells. Whether, IL‐12 regulates OIP‐1 expression in the bone microenvironment is unclear. Real‐time PCR analysis revealed that IL‐12 treatment significantly enhanced OIP‐1 mRNA expression in human bone marrow mononuclear cells. Because IL‐12 induces IFN‐γ production by T cells, we tested whether IFN‐γ participates in IL‐12 stimulation of OIP‐1 gene expression in these cells. IL‐12 treatment in the presence of IFN‐γ neutralizing antibody significantly increased OIP‐1 mRNA expression, suggesting that IL‐12 directly regulates OIP‐1 gene expression. Interestingly, real‐time PCR analysis demonstrated that IL‐12 induces OIP‐1 expression (3.2‐fold) in CD4+ T cells; however, there was no significant change in CD8+ T cells. Also, IL‐12 (10 ng/ml) treatment of Jurkat cells transfected with OIP‐1 gene (?1 to ?1,988 bp) promoter‐luciferase reporter plasmid demonstrated a 5‐fold and 2.7‐fold increase in OIP‐1 gene promoter activity in the presence and absence of antibody against IFN‐γ, respectively. We showed that STAT‐1,3 inhibitors treatment significantly decreased IL‐12 stimulated OIP‐1 promoter activity. Chromatin immunoprecipitation (ChIP) assay confirmed STAT‐3, but not STAT‐1 binding to the OIP‐1 gene promoter in response to IL‐12 stimulation. These results suggest that IL‐12 stimulates the OIP‐1 gene expression through STAT‐3 activation in CD4+ T cells. J. Cell. Biochem. 107: 104–111, 2009. © 2009 Wiley‐Liss, Inc.     

Splenic dendritic cell subsets prime and boost CD8 T cells and are involved in the generation of effector CD8 T cells

The ability of the dendritic cell (DC) subsets, CD8alpha+ and CD8alpha- DCs, to initiate a CD8 T cell response or to activate memory CD8 T cells and generate effector CD8 T cells has been controversial. In this study, we analyse the capacity of splenic DC subsets to induce CD8 T cell responses to a CD8 T cell epitope (pb9) of a malaria antigen. The administration of peptide-pulsed CD8alpha- or CD8alpha+ DCs primes and boosts a primed CD8 T cell response against the malaria epitope. In vitro, depletion of CD11c(+) DCs from mouse splenocytes, immunised with recombinant vaccinia virus Ankara (MVA) expressing pb9 epitope, significantly reduced the generation of pb9-specific IFNgamma producing effector CD8 T cells, indicating that splenic DCs are involved in the development of pb9-specific IFNgamma producing effector cells. Taken together, this result shows that both DC subsets have the ability to prime and boost CD8 T cell responses and are involved in the activation of memory CD8 T cells.     

Activation of Unusual Mac-1+CD4− CD8− T Cells Bearing αβ Antigen Receptor in Murine Lungs during Infection with Mycobacterium bovis BCG: Regulation by Interferon-γ

We have recently (Kawakami et al, Immunol. Lett. 1995;46: 143) demonstrated that unusual Mac-1⁺CD4^?CD8^? T cells bearing αβ antigen receptor (Mac-1⁺ αβ T cells) reside in a considerable proportion in murine lungs. The present study was performed to examine the dynamics of accumulation of these cells in the lungs following intravenous administration of Mycobacterium bovis BCG (BCG). Mac-1⁺ αβ T cells accumulated rapidly 24 hr after infection, followed by a gradual increase over the observation period of 15 days. Furthermore, the expression of Ia, ICAM-1 and FcγR II/III on their surface intensified dramatically after BCG infection. The kinetics of enhancement of Ia expression was slower than that of ICAM-1, with the maximum level attained in one day in the latter molecule but in two weeks in the former. Neutralization of endogenous IFN-γ by specific mAb completely blocked the augmented expression of Ia on Mac-1⁺ αβ T cells after BCG infection, but did not have any significant effect on that of ICAM-1. In contrast, in vivo administration of IFN-γ enhanced the expression of ICAM-1 as well as that of Ia. Our results indicate that accumulation of Mac-1 αβ T cells within the lung is associated with a differential change in the expression of surface antigens, and suggest that these cells may play a role in the host defense against mycobacterial infection.     

Heterogeneity in phenotype and function of CD8+ and CD4/CD8 double‐negative Natural Killer T cell subsets in sooty mangabeys

Background We have recently reported the presence of CD8⁺ and CD4/8 double‐negative (DN) natural killer T (NKT) lymphocytes in sooty mangabeys. To investigate differences in the two NKT cell subsets, we compared the phenotype and function of sooty mangabey CD8⁺ and DN NKT cells. Methods Flow‐sorted NKT lymphocytes from one SIV‐negative sooty mangabey were subjected to limiting dilution cloning. Invariant NKT clones were characterized by flow cytometry and cytokine ELISA. Results The majority of NKT clones displayed an effector memory phenotype and expressed CXCR3 and NKG2D. While CD8⁺ NKT subsets expressed significantly higher levels of granzyme B and perforin and produced more IFN‐γ, the DN NKT subsets secreted significantly more IL‐4, IL‐13, and IL‐10. Conclusions The Th1 and Th2 cytokine bias of CD8⁺ and DN NKT cells, respectively, indicates the presence of functionally heterogeneous populations of NKT cells in sooty mangabeys.     

Type D SRV-2 virus-specific CD8+ and CD4- CD8- T cells that regulate virus-induced T cell proliferation in Celebes macaques

These studies defined SRV-2 envelope peptides 96-102, 127-152, and 233-249 as T cell epitopes that induce significant T cell proliferation. Peripheral blood lymphocytes of Celebes macaques (Macaca nigra) exposed to SRV-2 and currently virus^- antibody⁺, cultured with SRV-2 virus show strongly suppressed T cell responses and have two immunoregulatory T cell populations.     

Effects of Sirolimus treatment on patients with β‐Thalassemia: Lymphocyte immunophenotype and biological activity of memory CD4 + and CD8 + T cells

Inhibitors of the mammalian target of rapamycin (mTOR) have been proposed to improve vaccine responses, especially in the elderly. Accordingly, testing mTOR inhibitors (such as Sirolimus) and other geroprotective drugs might be considered a key strategy to improve overall health resilience of aged populations. In this respect, Sirolimus (also known as rapamycin) is of great interest, in consideration of the fact that it is extensively used in routine therapy and in clinical studies for the treatment of several diseases. Recently, Sirolimus has been considered in laboratory and clinical studies aimed to find novel protocols for the therapy of hemoglobinopathies (e.g. β‐Thalassemia). The objective of the present study was to analyse the activity of CD4⁺ and CD8⁺ T cells in β‐Thalassemia patients treated with Sirolimus, taking advantages from the availability of cellular samples of the {"type":"clinical-trial","attrs":{"text":"NCT03877809","term_id":"NCT03877809"}}NCT03877809 clinical trial. The approach was to verify IFN‐γ releases following stimulation of peripheral blood mononuclear cells (PBMCs) to stimulatory CEF and CEFTA peptide pools, stimulatory for CD4⁺ and CD8⁺ T cells, respectively. The main results of the present study are that treatment of β‐Thalassemia patients with Sirolimus has a positive impact on the biological activity and number of memory CD4⁺ and CD8⁺ T cells releasing IFN‐γ following stimulation with antigenic stimuli present in immunological memory. These data are to our knowledge novel and in our opinion of interest, in consideration of the fact that β‐Thalassemia patients are considered prone to immune deficiency.     

Rapid G0/1 transition and cell cycle progression in CD8+ T cells compared to CD4+ T cells following in vitro stimulation

T‐cell population consists of two major subsets, CD4⁺ T cells and CD8⁺ T cells, which can be distinguished by the expression of CD4 or CD8 molecules, respectively. Although they play quite different roles in the immune system, many of their basic cellular processes such as proliferation following stimulation are presumably common. In this study, we have carefully analyzed time–course of G0/1 transition as well as cell cycle progression in the two subsets of quiescent T‐cell population following in vitro growth stimulation. We found that CD8⁺ T cells promote G0/1 transition more rapidly and drive their cell cycle progression faster compared to CD4⁺ T cells. In addition, expression of CD25 and effects of its blockade revealed that IL‐2 is implicated in the rapid progression, but not the earlier G0/1 transition, of CD8⁺ T cells.     

α‐galactosylceramide generates lung regulatory T cells through the activated natural killer T cells in mice

Our previous study showed that intraperitoneal injection of α‐galactosylceramide (α‐GalCer) has the ability to activate lung iNKT cells, but α‐GalCer‐activated iNKT cells do not result in airway inflammation in wild‐type (WT) mice. Many studies showed that iNKT cells had the capacity to induce Treg cells, which gave rise to peripheral tolerance. Therefore, we examined the influence of intraperitoneal administration of α‐GalCer on the expansion and suppressive activity of lung Treg cells using iNKT cell‐knockout mice and co‐culture experiments in vitro. We also compared airway inflammation and airway hyperresponsiveness (AHR) after α‐GalCer administration in specific anti‐CD25 mAb‐treated mice. Our data showed that intraperitoneal injection of α‐GalCer could promote the expansion of lung Treg cells in WT mice, but not in iNKT cell‐knockout mice. However, α‐GalCer administration could not boost suppressive activity of Treg cells in WT mice and iNKT cell‐knockout mice. Interestingly, functional inactivation of Treg cells could induce airway inflammation and AHR in WT mice treated with α‐GalCer. Furthermore, α‐GalCer administration could enhance iNKT cells to secrete IL‐2, and neutralization of IL‐2 reduced the expansion of Treg cells in vivo and in vitro. Thus, intraperitoneal administration of α‐GalCer can induce the generation of lung Treg cells in mice through the release of IL‐2 by the activated iNKT cells.     

Tumor eradication by hetIL-15 locoregional therapy correlates with an induced intratumoral CD103intCD11b+ dendritic cell population

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Exposure of normal monocyte-derived dendritic cells to human immunodeficiency virus type-1 particles leads to the induction of apoptosis in co-cultured CD4+ as well as CD8+ T cells

The depletion of immune T cells by human immunodeficiency virus type-1 (HIV-1) infection is a major mechanism involved in the pathogenesis of AIDS. Here, we examined a possible effector function of blood monocyte-derived dendritic cells (DCs) to induce apoptosis in bystander CD4+ and CD8+ T cells. The DCs were generated by culturing monocytes in the presence of granulocyte-macrophage colony-stimulating factor and interleukin-4. The DCs exposed to HIV-1 particles were co-cultured with healthy donor-derived blood T cells at a ratio of 1:20. Analyses by percent cell mortality, staining with propidium iodide and reactivity with Annexin V revealed the induction of apoptosis in both CD4+ and CD8+ target T cells. Further, this apoptosis occurred without stimulation with mitogens when the cell cycle of target T cells shifted from G0 to G1, probably due to the mitogenic effect of the DCs. Thus, induction of apoptosis in both CD4+ and CD8+ T cells occurred via interaction with DCs adsorbed with HIV-1 particles.     

4-1BB costimulation enhances HSV-1-specific CD8+ T cell responses by the induction of CD11c+CD8+ T cells

Since 4-1BB plays a predominant role in CD8+ T cell responses, we investigated the effects of 4-1BB triggering on the primary and memory CD8+ T responses to HSV-1 infection. 4-1BB was detected on 10-15% of CD4+ and CD8+ T cells following the infection. 4-1BB-positive T cells were in the proliferative mode and showed the enhanced expression of anti-apoptotic proteins. Agonistic anti-4-1BB treatment exerted preferential expansion of CD8+ T cells and gB/H-2Kb-positive CD8+ T cells, and enhanced cytotoxicity against HSV-1 that was mainly mediated by CD11c+CD8+ T cells. CD11c+CD8+ T cells were re-expanded following re-challenge with HSV-1 at post-infection day 50, indicating that CD11c+CD8+ phenotype was maintained in memory CD8+ T cell pool. Our studies demonstrated that 4-1BB stimulation enhanced both primary and memory anti-HSV-1 CD8+ T cell responses, which was mediated by a massive expansion of antigen-specific CD11c+CD8+ T cells.