Upregulation of CD94 on CD8+T cells in anterior chamber-associated immune deviation

The Basis and Advances in Clinical Application of Cytomegalovirus-Specific Cytotoxic T Cell Immunotherapy for Glioblastoma Multiforme

A high percentage of malignant gliomas are infected by human cytomegalovirus (HCMV), and the endogenous expression of HCMV genes and their products are found in these tumors. HCMV antigen expression and its implications in gliomagenesis have emerged as a promising target for adoptive cellular immunotherapy (ACT) strategies in glioblastoma multiforme (GB) patients. Since antigen-specific T cells in the tumor microenvironments lack efficient anti-tumor immune response due to the immunosuppressive nature of glioblastoma, CMV-specific ACT relies on in vitro expansion of CMV-specific CD8+ T cells employing immunodominant HCMV antigens. Given the fact that several hurdles remain to be conquered, recent clinical trials have outlined the feasibility of CMV-specific ACT prior to tumor recurrence with minimal adverse effects and a substantial improvement in median overall survival and progression-free survival. This review discusses the role of HCMV in gliomagenesis, disease prognosis, and recent breakthroughs in harnessing HCMV-induced immunogenicity in the GB tumor microenvironment to develop effective CMV-specific ACT.

CD8(+) T-Cells as Immune Regulators of Multiple Sclerosis

The vast majority of studies regarding the immune basis of MS (and its animal model, EAE) have largely focused on CD4(+) T-cells as mediators and regulators of disease. Interestingly, CD8(+) T-cells represent the predominant T-cell population in human MS lesions and are oligoclonally expanded at the site of pathology. However, their role in the autoimmune pathologic process has been both understudied and controversial. Several animal models and MS patient studies support a pathogenic role for CNS-specific CD8(+) T-cells, whereas we and others have demonstrated a regulatory role for these cells in disease. In this review, we describe studies that have investigated the role of CD8(+) T-cells in MS and EAE, presenting evidence for both pathogenic and regulatory functions. In our studies, we have shown that cytotoxic/suppressor CD8(+) T-cells are CNS antigen-specific, MHC class I-restricted, IFNγ- and perforin-dependent, and are able to inhibit disease. The clinical relevance for CD8(+) T-cell suppressive function is best described by a lack of their function during MS relapse, and importantly, restoration of their suppressive function during quiescence. Furthermore, CD8(+) T-cells with immunosuppressive functions can be therapeutically induced in MS patients by glatiramer acetate (GA) treatment. Unlike CNS-specific CD8(+) T-cells, these immunosuppressive GA-induced CD8(+) T-cells appear to be HLA-E restricted. These studies have provided greater fundamental insight into the role of autoreactive as well as therapeutically induced CD8(+) T-cells in disease amelioration. The clinical implications for these findings are immense and we propose that this natural process can be harnessed toward the development of an effective immunotherapeutic strategy.

Determining immune components necessary for progression of pigment dispersing disease to glaucoma in DBA/2J mice

Background

The molecular mechanisms causing pigment dispersion syndrome (PDS) and the pathway(s) by which it progresses to pigmentary glaucoma are not known. Mutations in two melanosomal protein genes (Tyrp1^b and Gpnmb^R150X) are responsible for pigment dispersing iris disease, which progresses to intraocular pressure (IOP) elevation and subsequent glaucoma in DBA/2J mice. Melanosomal defects along with ocular immune abnormalities play a role in the propagation of pigment dispersion and progression to IOP elevation. Here, we tested the role of specific immune components in the progression of the iris disease and high IOP.

Results

We tested the role of NK cells in disease etiology by genetically modifying the B6.D2-Gpnmb^R150XTyrp1^b strain, which develops the same iris disease as DBA/2J mice. Our findings demonstrate that neither diminishing NK mediated cytotoxic activity (Prf1 mutation) nor NK cell depletion (Il2rg mutation) has any influence on the severity or timing of Gpnmb^R150XTyrp1^b mediated iris disease. Since DBA/2J mice are deficient in CD94, an important immune modulator that often acts as an immune suppressor, we generated DBA/2J mice sufficient in CD94. Sufficiency of CD94 failed to alter either the iris disease or the subsequent IOP elevation. Additionally CD94 status had no detected effect on glaucomatous optic nerve damage.

Conclusion

Our previous data implicate immune components in the manifestation of pigment dispersion and/or IOP elevation in DBA/2J mice. The current study eliminates important immune components, specifically NK cells and CD94 deficiency, as critical in the progression of iris disease and glaucoma. This narrows the field of possible immune components responsible for disease progression.

Influence of coffee (Coffea arabica) and galacto-oligosaccharide consumption on intestinal microbiota and the host responses

Although studies have reported numerous effects of coffee on human health, few studies have examined its specific effects on gut microbiota. This study aimed to clarify the influence of coffee and galacto-oligosaccharide (GOS) consumption on gut microbiota and host responses. After mice consumed coffee and GOS, their intestines were sampled, and the bacterial counts were measured with quantitative RT-PCR. Results showed that GOS consumption significantly increased total bacteria counts in the proximal colon. Although Escherichia coli and Clostridium spp. counts significantly decreased in the proximal colon, Bifidobacterium spp. counts increased remarkably in the same area. A bacterial growth inhibition assay was also conducted, and the results showed that E. coli growth was inhibited only by a coffee agar. Host responses were also investigated, revealing that coffee and GOS consumption remarkably increased aquaporin8 expression in the proximal colon. In conclusion, coffee has antibiotic effects, and GOS significantly decreased E. coli and Clostridium spp. counts, but increased Bifidobacterium spp. counts remarkably. Aquaporin8 expression was also increased with a mixture of coffee and GOS consumption. This is the first study to demonstrate that coffee consumption can regulate gut microbiota and increase aquaporin8, both of which are necessary for maintaining intestinal balance.

Common gamma chain cytokines promote rapid in vitro expansion of allo-specific human CD8+ suppressor T cells

Human CD8⁺ regulatory T cells, particularly the CD8⁺CD28⁻ T suppressor cells, have emerged as an important modulator of alloimmunity. Understanding the conditions under which these cells are induced and/or expanded would greatly facilitate their application in future clinical trials. In the current study, we develop a novel strategy that combines common gamma chain (γc) cytokines IL-2, IL-7 and IL-15 and donor antigen presenting cells (APCs) to stimulate full HLA-mismatched allogeneic human CD8⁺ T cells which results in significant expansions of donor-specific CD8⁺CD28⁻ T suppressor cells in vitro. The expanded CD8⁺CD28⁻ T cells exhibit increased expressions of CTLA-4, FoxP3, and CD25, while down-regulate expressions of CD56, CD57, CD127, and perforin. Furthermore, these cells suppress proliferation of CD4⁺ T cells in a contact-dependent and cytokine-independent manner. Interestingly, the specificity of suppression is restricted by the donor HLA class I antigens but promiscuous to HLA class II antigens, providing a potential mechanism for linked suppression. Taken together, our results demonstrate a novel role for common γc cytokines in combination with donor APCs in the expansion of donor-specific CD8⁺CD28⁻ T suppressor cells, and represent a robust strategy for in vitro generation of such cells for adoptive cellular immunotherapy in transplantation.

Immune amplification of murine CD8 suppressor T cells induced via an immune-privileged site: quantifying suppressor T cells functionally

Background

CD8⁺ suppressor T cells exert antigen-specific suppression of the expression of hypersensitivity by activated T cells. Therefore, CD8⁺ suppressor T cells serve a major regulatory role for the control of active immunity. Accordingly, the number and/or activity of CD8⁺ suppressor T cells should be influenced by an immune response to the antigen. To test this hypothesis we used an adoptive transfer assay that measures the suppression of the expression of delayed-type hypersensitivity (DTH) by CD8⁺ suppressor T cells to quantify the antigen-specific suppression of DTH by these suppressor T cells.

Methods

Suppressor T cells were induced in the spleens of mice by the injection of antigen into the anterior chamber of an eye. Following this injection, the mice were immunized by the same antigen injected into the anterior chamber. Spleen cells recovered from these mice (AC-SPL cells) were titrated in an adoptive transfer assay to determine the number of AC-SPL cells required to effect a 50% reduction of antigen-induced swelling (Sw50) in the footpad of immunized mice challenged by antigen.

Results

Suppression of the expression of DTH is proportional to the number of AC-SPL cells injected into the site challenged by antigen. The number of AC-SPL cells required for a 50% reduction in DTH-induced swelling is reduced by injecting a cell population enriched for CD8⁺ AC-SPL cells. Immunizing the mice receiving intracameral antigen to the same antigen decreases the RSw50 of AC-SPL cells required to inhibit the expression of DTH.

Conclusions

The results provide the first quantitative demonstration that the numbers of antigen-specific splenic CD8⁺ suppressor T cells are specifically amplified by antigen during an immune response.

CD8+ Tregs in lupus, autoimmunity, and beyond

While CD4(+)CD25(high) regulatory T cells (Tregs) have garnered much attention for their role in the maintenance of immune homeostasis, recent findings have shown that subsets of CD8(+) T cells (CD8(+) Tregs) display immunoregulatory functions as well. Both CD4(+) Tregs and CD8(+) Tregs appear impaired in number and/or function in several autoimmune diseases and in experimental animal models of autoimmunity, suggesting the possibility of immunotherapeutic targeting of these cells for improved management of autoimmune conditions. Our group has developed a strategy to induce CD8(+) Tregs in autoimmune mice through the use of a tolerogenic self-peptide, and new information has been gained on the phenotype, function and role of induced CD8(+) Tregs in autoimmunity. Here we present an overview of the role and mechanisms of action of CD8(+) Tregs in autoimmunity, with a special focus on lupus. We also discuss the potential role of CD8(+) Tregs in other diseases, including chronic infection and cancer.

The suppression of hypersensitivity by ocular-induced CD8(+) T cells requires compatibility in the Qa-1 haplotype

The injection of antigen into the anterior chamber (AC, intracameral injection) of a murine eye induces the generation of splenic CD8(+) regulatory T cells (AC-SPL cells) that effect the antigen-specific suppression of a delayed-type hypersensitivity (DTH) reaction. Here we show (i) for the first time that the local antigen-specific suppression of DTH-induced swelling in immunized mice either by an intracameral injection of antigen or by the direct injection of CD8(+) AC-SPL cells into an antigen-challenged site is associated with an absence of infiltrated mononuclear cells, (ii) that the local antigen-specific suppression of the DTH reaction by CD8(+) AC-SPL cells requires compatibility between the Qa-1 but not H2 antigen haplotype of the immunized recipient and the injected AC-SPL regulatory T cells, (iii) that the suppression of the DTH reaction by CD8(+) AC-SPL cells requires the expression of Qa-1 but not H2 antigens and is not due to bystander suppression.