Galectin-1 reduction and changes in T regulatory cells may play crucial roles in patients with unexplained recurrent spontaneous abortion

To investigate the changes of Galectin-1 and T-lymphocyte phenotypes in unexplained recurrent spontaneous abortion (URSA). Totally 60 participants were recruited and divided into 3 groups in average: pregnant patients with URSA (URSA group), normal early pregnant women with induced abortion (IA group) and normal non-pregnant women (control group). After the tissue and blood sample were collected, Galectin-1 was measured using enzyme-linked immunosorbent assay. Then the proportion of T regulatory cells was determined by flow cytometry. The expression levels of Galectin-1 in IA group and URSA group was significantly higher than that in the control group (24.30 ± 3.06 and 6.23 ± 2.41 vs. 1.30 ± 0.66, P < 0.05). Besides, the expression level of Galectin-1 in URSA group was lower than that in IA group (P < 0.05). The percentage of CD4⁺CD25⁺Foxp3⁺ Tregs was lower in URSA group than IA group (0.77 ± 0.31 vs. 1.00 ± 0.35, P < 0.05) and the ratio of CD4⁺CD25⁺Foxp3⁺/CD4⁺ in URSA group was also obviously lower than that in IA and control group (P < 0.05). Galectin-1 and CD4⁺CD25⁺Foxp3⁺ may play essential roles in maintaining a normal pregnancy and their reduction may involve in the pathogenesis of URSA.     

Multifunctional cytomegalovirus (CMV)-specific CD8+ T cells are not restricted by telomere-related senescence in young or old adults

Antigen-specific multifunctional T cells that secrete interferon-γ, interleukin-2 and tumour necrosis factor-α simultaneously after activation are important for the control of many infections. It is unclear if these CD8⁺ T cells are at an early or late stage of differentiation and whether telomere erosion restricts their replicative capacity. We developed a multi-parameter flow cytometric method for investigating the relationship between differentiation (CD45RA and CD27 surface phenotype), function (cytokine production) and replicative capacity (telomere length) in individual cytomegalovirus (CMV) antigen-specific CD8⁺ T cells. This involves surface and intracellular cell staining coupled to fluorescence in situ hybridization to detect telomeres (flow-FISH). The end-stage/senescent CD8⁺ CD45RA⁺ CD27⁻ T-cell subset increases significantly during ageing and this is exaggerated in CMV immune-responsive subjects. However, these end-stage cells do not have the shortest telomeres, implicating additional non-telomere-related mechanisms in inducing their senescence. The telomere lengths in total and CMV (NLV)-specific CD8⁺ T cells in all four subsets defined by CD45RA and CD27 expression were significantly shorter in old compared with young individuals in both a Caucasian and an Asian cohort. Following stimulation by anti-CD3 or NLV peptide, similar proportions of triple-cytokine-producing cells are found in CD8⁺ T cells at all stages of differentiation in both age groups. Furthermore, these multi-functional cells had intermediate telomere lengths compared with cells producing only one or two cytokines after activation. Therefore, global and CMV (NLV)-specific CD8⁺ T cells that secrete interferon-γ, interleukin-2 and tumour necrosis factor-α are at an intermediate stage of differentiation and are not restricted by excessive telomere erosion.     

Killer cell immunoglobulin receptor profile on CD4+ CD28− T cells and their pathogenic role in non‐dialysis‐dependent and dialysis‐dependent chronic kidney disease patients

There is a progressive increase in cardiovascular disease with declining renal function, unexplained by traditional risk factors. A CD4⁺ T-cell subpopulation (CD4⁺ CD28⁻), activated by human heat-shock protein 60 (hHSP 60), expands in patients with acute coronary syndrome and is associated with vascular damage. These cells exhibit cytotoxicity via expression of activating killer cell-immunoglobulin-like receptor KIR2DS2, mainly in the absence of inhibitory KIR2DL3. We investigated expansion of these cells and the pathogenic role of the KIR in non-dialysis-dependent chronic kidney disease (NDD-CKD) and end-stage haemodialysis-dependent renal disease (HD-ESRD) patients. CD4⁺ CD28⁻ cells were present in 27% of the NDD-CKD and HD-ESRD patients (8–11% and 10–11% of CD4⁺ compartment, respectively). CD4⁺ CD28⁻ cells were phenotyped for KIR and DAP12 expression. Cytotoxicity was assessed by perforin and pro-inflammatory function by interferon-γ expression on CD4⁺ CD28⁻ clones (NDD-CKD n = 97, HD-ESRD n = 262). Thirty-four per cent of the CD4⁺ CD28⁻ cells from NDD-CKD expressed KIR2DS2 compared with 56% in HD-ESRD patients (P = 0·03). However, 20% of clones expressed KIR2DL3 in NDD-CKD compared with 7% in HD-ESRD patients (P = 0·004). DAP12 expression in CD28⁻ 2DS2⁺ clones was more prevalent in HD-ESRD than NDD-CKD (92% versus 60%; P < 0·001). Only 2DS2⁺ 2DL3⁻ DAP12⁺ clones were cytotoxic in response to hHSP 60. CD4⁺ CD28⁻ cells exhibited increased KIR2DS2, reduced KIR2DL3 and increased DAP12 expression in HD-ESRD compared with NDD-CKD patients. These findings suggest a gradual loss of expression, functionality and protective role of inhibitory KIR2DL3 as well as increased cytotoxic potential of CD4⁺ C28⁻ cells with progressive renal impairment. Clonal expansion of these T cells may contribute to heightened cardiovascular events in HD-ESRD.     

Association of T cell dysfunction with the presence of IgG autoantibodies on CD4+ lymphocytes in haemophilia patients; results of a 10-year study

HIV induces progressive dysfunction followed by numerical depletion of CD4⁺ lymphocytes. IgG autoantibodies and gp120-containing immune complexes have been implicated in the pathogenesis of AIDS. We carried out a longitudinal study in 19 HIV^– and 72 HIV⁺ haemophilia patients over a 10-year period in order to investigate a possible relationship between the occurrence of autoantibodies and CD4⁺ lymphocyte changes. IgM, IgG, C3d and gp120 on the surface of CD4⁺ lymphocytes were determined in heparinized whole blood with flow cytometry and double-fluorescence. The in vitro response of autoantibody-coated cells was tested in cell cultures with concanavalin A (Con A), phytohaemagglutinin (PHA), pokeweed mitogen (PWM), anti-CD3 MoAb or pooled allogeneic stimulator cells (MLC). After a 10-year follow up, 12 of 71 HIV⁺ and 16 of 19 HIV^– haemophilia patients showed no evidence of immunoglobulins on circulating CD4⁺ lymphocytes. HIV^– haemophilia patients without autoantibodies had CD4⁺and CD8⁺ cell counts in the normal range (957 ± 642/μl and 636 ± 405/μl) and normal T cell responses in vitro (mean relative response (RR) ≥ 0.7). In contrast, HIV⁺ haemophilia patients showed immunological abnormalities which were associated with the autoantibody and immune complex load of CD4⁺ blood lymphocytes. HIV⁺ patients without autoantibodies had a mean CD4⁺ lymphocyte count of 372 ± 274/μl, a mean CD8⁺ lymphocyte count of 737 ± 435/μl, and normal T lymphocyte stimulation in vitro (mean RR ≥ 0.7). HIV⁺ patients with complement-fixing IgM on CD4⁺ lymphocytes had somewhat lower CD4⁺ (255 ± 246/μl, P= NS) and CD8⁺ (706 ± 468/μl, P= NS) lymphocyte numbers, and also normal T lymphocyte stimulation (mean RR ≥ 0.7) in vitro. However, patients with complement-fixing IgG autoantibodies showed a strong decrease of CD4⁺ (150 ± 146/μl, P< 0.02) and CD8⁺ (360 ± 300/μl, P< 0.02) lymphocytes and impaired CD4⁺ lymphocyte stimulation in vitro with a mean RR of 0.5 ± 0.5 for Con A (P= NS), 0.7 ± 0.8 for PHA (P< 0.03), 0.4 ± 0.4 for PWM (P= NS), 0.8 ± 1.2 for anti-CD3 MoAb (P< 0.04) and 0.7 ± 1.0 for pooled allogeneic stimulator cells (P= 0.05). Patients with gp120-containing immune complexes on CD4⁺ blood lymphocytes demonstrated strongly decreased CD4⁺(25 ± 35/μl, P< 0.0001) and CD8⁺ (213 ± 212/μl, P< 0.006) lymphocyte counts as well as strongly impaired T lymphocyte responses in vitro upon stimulation with PHA (RR 0.2 ± 0.1, P < 0.02), PWM (RR 0.2 ± 0.2, P= 0.05), anti-CD3 MoAb (RR 0.1 ± 0.1, P< 0.04), and allogeneic stimulator cells (RR 0.2 ± 0.1, P< 0.02). These data led us to speculate that autoantibody formation against CD4⁺ lymphocytes is an important mechanism in the pathogenesis of AIDS. We hypothesize that autoantibodies against circulating CD4⁺ lymphocytes inhibit CD4⁺ cell function, especially the release of cytokines, and induce CD4⁺ cell depletion. The reduction and dysfunction of CD4⁺ lymphocytes may be responsible for the CD8⁺ cell depletion observed in HIV⁺ patients.     

CD4+CD29+T cells are blamed for the persistent inflammatory response in ulcerative colitis

Ulcerative colitis (UC) is a chronic gastrointestinal disorder eliciting occurrence of colorectal cancer, the third most common human malignancy. The diagnosis of UC is based on clinical symptoms combined with typical findings on endoscopy, radiology, and ultimately pathology. We investigated the variation trend of CD4⁺CD29⁺T cells together with MPO, VCAM-1 in different periods of rat UC model and UC patients. We also evaluated the relationship between CD4⁺CD29⁺T cells and disease severity. UC model was induced by administering DNCB liquid and acetate solution. We found upregulated expression of CD4⁺CD29⁺T cells in both peripheral blood and colon from rats, and a similar trend for MPO and VCAM-1 in colon (P < 0.05); the expression was especially enhanced in UC rats at two weeks after the model was established (P < 0.01). Such upregulation was also indicated in active and remission UC patients as compared to the healthy and enteritis groups (P < 0.05), with the highest expression level detected in the active UC patients (P < 0.01). Pearson correlation analysis showed a positive correlation of CD4⁺CD29⁺T cells in rat and human peripheral blood with DAI score (r_rat = 0.712, r_human = 0.677, P < 0.01), and MPO in colon (r_rat = 0.514, r_human = 0.682, P < 0.05). These results suggest that CD4⁺CD29⁺T cells may act as major effector cell subsets in persistent inflammatory responses for UC and that infiltration into colon inflammation may be induced by the combination of VCAM-1 and CD29.     

Involvement of Foxp3-expressing CD4+ CD25+ regulatory T cells in the development of tolerance induced by transforming growth factor-beta2-treated antigen-presenting cells

A growing body of evidence has shown that professional antigen-presenting cells (APC) treated with transforming growth factor-β (TGF-β) can induce a systemic antigen (Ag)-specific tolerance, similar to anterior chamber-associated immune deviation (ACAID). However, the exact mechanism for immune tolerance induced by TGF-β-treated APC has not been elucidated. In this study, we showed that intravenous injection of ovalbumin (OVA)-pulsed APC treated with TGF-β₂ induced a peripheral tolerance as evidenced by an impaired delayed-type hypersensitivity (DTH) response. CD4⁺ T cells from mice receiving an intravenous injection of TGF-β₂-treated APC pulsed with OVA could adoptively transfer a specific tolerance to naïve mice. An increased frequency of FoxP3-expressing CD4⁺ CD25⁺ T cells was observed in mice with tolerance. CD4⁺CD25⁺ T cells from TGF-β₂-treated APC-injected mice produced a large amount of TGF-β₁ and exhibited an in vitro antigen-specific suppressive activity. CD4⁺ CD25⁺ T cells from TGF-β₂-treated APC-injected mice were able to inhibit the antigen-specific DTH response significantly when adoptively transferred to naïve mice. These results indicate that FoxP3-expressing CD4⁺ CD25⁺ T cells might be actively involved in the development of tolerance induced by TGF-β₂-treated APC.     

CD8+ CD28− T cells in vertically HIV-infected children

To evaluate whether vertical HIV infection interferes with the expression of CD28 on T lymphocytes, 25 HIV-infected children and 29 seroreverted children born to HIV⁺ mothers were studied. The percentage of CD28⁻ cells among CD8⁺ T lymphocytes was higher in HIV-infected children than in controls (P < 0.001). In fact, in HIV-infected children, this percentage was elevated from the first year of life, while in healthy seroreverted children, the proportion of CD28⁻ cells among CD8⁺ cells rose progressively with age (r = 0.49; P = 0.008). In HIV⁺ children, the CD8⁺ CD28⁻, but not CD8⁺ CD28⁺ cell proportion was significantly correlated with immunological markers of disease progression, such as CD4⁺ cell loss (r = −0.65; P < 0.001) and the level of in vitro spontaneous lymphocyte apoptosis (r = 0.53; P = 0.03).     

Type 2 diabetes mellitus is associated with altered CD8+ T and natural killer cell function in pulmonary tuberculosis

Type 2 diabetes mellitus (DM) is associated with expanded frequencies of mycobacterial antigen-specific CD4⁺ T helper type 1 (Th1) and Th17 cells in individuals with active pulmonary tuberculosis (TB). No data are available on the role of CD8⁺ T and natural killer (NK) cells in TB with coincident DM. To identify the role of CD8⁺ T and NK cells in pulmonary TB with diabetes, we examined mycobacteria-specific immune responses in the whole blood of individuals with TB and DM (TB-DM) and compared them with those without DM (TB-NDM). We found that TB-DM is characterized by elevated frequencies of mycobacterial antigen-stimulated CD8⁺ T cells expressing type 1 [interferon-γ and interleukin-2 (IL-2)] and type 17 (IL-17F) cytokines. We also found that TB-DM is characterized by expanded frequencies of TB antigen-stimulated NK cells expressing type 1 (tumour necrosis factor-α) and type 17 (IL-17A and IL-17F) cytokines. In contrast, CD8⁺ T cells were associated with significantly diminished expression of the cytotoxic markers perforin, granzyme B and CD107a both at baseline and following antigen or anti-CD3 stimulation, while NK cells were associated with significantly decreased antigen-stimulated expression of CD107a only. This was not associated with alterations in CD8⁺ T-cell or NK cell numbers or subset distribution. Therefore, our data suggest that pulmonary TB complicated with type 2 DM is associated with an altered repertoire of cytokine-producing and cytotoxic molecule-expressing CD8⁺ T and NK cells, possibly contributing to increased pathology.     

CD8+ T cells and not CD4+ T cells are hyporesponsive to CD28- and CD40L-mediated activation in HIV-infected subjects

T cell dysfunction in HIV-infected subjects could be the consequence of altered sensitivity of CD4⁺ or CD8⁺ T cells to various costimulatory signals. Therefore, we studied proliferation and cytokine production in highly purified CD8⁺ and CD4⁺ T cells from HIV-infected and HIV⁻ subjects, induced by co-activation via cell-bound CD80, CD86 and CD40 or by allo-activation. Regardless of the nature of the first and the costimulatory signal, CD8⁺ T cells from patients proliferated consistently less than controls, while responses from CD4⁺ T cells were similar in patients and controls. This phenomenon was observed after ligation of CD28 combined with anti-CD3 or phorbol myristate acetate (PMA), but also after allogeneic stimulation and after activation by CD40 and anti-CD3. Anti-CD3 combined with CD80 or CD86 induced a mixed Th1/Th2-type cytokine profile in both CD4⁺ and CD8⁺ T cells from controls, whereas anti-CD3 plus CD40 induced only low levels of Th2-type cytokines and no interferon-gamma (IFN-γ) in CD4⁺ T cells. Compared with controls, CD4⁺ T cells from patients produced slightly lower levels of IL-10 but equal amounts of IFN-γ, IL-4 and IL-5, while CD8⁺ T cells from patients produced less of all cytokines tested. In conclusion, responses of purified CD4⁺ T cells from HIV⁺ subjects to various costimulatory pathways are relatively intact, whereas CD8⁺ T cells are hyporesponsive at the level of proliferation and cytokine production. A generalized intrinsic CD8⁺ T cell failure might contribute to viral and neoplastic complications of HIV infection.     

Anomalies of the CD8+ T cell pool in haemochromatosis: HLA-A3-linked expansions of CD8+CD28− T cells

The present study consists of a phenotypic and functional characterization of peripheral blood T lymphocytes in a group of 21 patients with hereditary haemochromatosis (HH), an MHC class I-linked genetic disease resulting in iron overload, and a group of 30 healthy individuals, both HLA-phenotyped. The HH patients studied showed an increased percentage of CD8⁺ CD28⁻ T cells with a corresponding reduction in the percentage of CD8⁺ CD28⁺ T cells in peripheral blood relative to healthy blood donors. No anomalies of CD28 expression were found in the CD4⁺ subset. The presence of the HLA-A3 antigen but not age accounted for these imbalances. Thus, an apparent failure of the CD8⁺ CD28⁺ T cell population ‘to expand’, coinciding with an ‘expansion’ of CD8⁺ CD28⁻ T cells in peripheral blood of HLA-A3⁺ but not HLA-A3⁻ HH patients was observed when compared with the respective HLA-A3-matched control group. A significantly higher percentage of HLA-DR⁺ but not CD45RO⁺ cells was also found within the peripheral CD8⁺ T cell subset in HH patients relative to controls. Phytohaemagglutinin (PHA) stimulation of peripheral blood mononuclear cells (PBMC) for 5 days showed: (i) that CD8⁺ CD28⁺ T cells both in controls and HH were able to expand in vitro; (ii) that CD8⁺ CD28⁻ T cells decreased markedly after activation in controls but not in HH patients. Moreover, functional studies showed that CD8⁺ cytotoxic T lymphocytes (CTL) from HH patients exhibited a diminished cytotoxic activity (approx. two-fold) in standard ⁵¹Cr-release assays when compared with CD8⁺ CTL from healthy controls. The present results provide additional evidence for the existence of phenotypic and functional anomalies of the peripheral CD8⁺ T cell pool that may underlie the clinical heterogeneity of this iron overload disease. They are of particular relevance given the recent discovery of a novel mutated MHC class I-like gene in HH.     

Quantitative T cell subsets profile in peripheral blood from patients with idiopathic inflammatory myopathies: tilting the balance towards proinflammatory and pro-apoptotic subsets

The role of T cells in idiopathic inflammatory myopathies (IIM) is not yet clear. Some alterations in certain subsets have been reported in inflamed muscle cells. However, a broad quantitative assessment of peripheral T cell subsets has not been evaluated. The aim of this study was to address the quantitative profile of potential pathogenic T cell subsets, namely follicular helper T cells (Tfh), T helper type 17 (Th17), CD28^null and regulatory T cells (T_regs) in peripheral blood from IIM patients. Thirty IIM patients and 30 age- and gender-matched healthy donors were included. Peripheral blood mononuclear cells were isolated. T cell subsets were evaluated by flow cytometry, as follows: Tfh (CD4⁺CXCR5⁺) and its subsets Tfh1 (CXCR3⁺CCR6⁻), Tfh2 (CXCR3⁻CCR6⁻), Tfh17 (CXCR3⁻CCR6⁺), Th17 (CD4⁺IL17A⁺), CD28^null (CD4⁺CD28⁻CD244⁺) and T_regs (CD4⁺CD25^highforkhead box protein 3 (FoxP3⁺); CD8⁺CD25^highFoxP3⁺). Percentage, absolute numbers and mean fluorescence intensity were analysed. We found increased numbers of total Tfh cells (28 ± 8·16 versus 6·64 ± 1·29, P = 0·031) in IIM patients when compared to healthy controls. Moreover, this increment was dependent upon Tfh2 and Tfh17 (Tfh2:9·49 ± 2·19 versus 1·66 ± 0·46, P = 0·005; Tfh17 9·48 ± 2·83 versus 1·18 ± 0·21, P = 0·014). Also, IIM patients showed higher numbers of Th17 cells (30·25 ± 6·49 versus 13·46 ± 2·95, P = 0·031) as well as decreased number of T_regs (5·98 ± 1·61 versus 30·82 ± 8·38, P = 0·009). We also found an expansion of CD28^null cells (162·88 ± 32·29 versus 64 ± 17·35, P = 0·015). Our data suggest that IIM patients are characterized by an expansion of peripheral proinflammatory T cells, such as Tfh and Th17, as well as pro-apoptotic CD28 null cells and a deficiency of suppressor populations of T_regs (CD4⁺ and CD8⁺).     

CD8+ T-cell recognition of a synthetic epitope formed by t-butyl modification

We set out to clone Bax-specific CD8⁺ T cells from peripheral blood samples of patients with primary chronic lymphocytic leukaemia. A number of clones were generated using a Bax peptide pool and their T-cell epitope was mapped to two peptides sharing a common 9-amino-acid sequence (LLSYFGTPT), restricted by HLA-A*0201. However, when these T-cell clones were tested against highly purified syntheses (> 95%) of the same peptide sequence, there was no functional response. Subsequent mass spectrometric analysis and HPLC fractionation suggested that the active component in the original crude peptide preparations (77% pure) was a peptide with a tert-butyl (tBu) modification of the tyrosine residue. This was confirmed by modification of the inactive wild-type sequence to generate functionally active peptides. Computer modelling of peptide:HLA-A*0201 structures predicted that the tBu modification would not affect interactions between peptide residues and the HLA binding site. However, these models did predict that the tBu modification of tyrosine would result in an extension of the side chain out of the peptide-binding groove up towards the T-cell receptor. This modified product formed < 1% of the original P603 crude peptide preparation and < 0·05% of the original 23-peptide mixture used for T-cell stimulation. The data presented here, illustrate the potential for chemical modifications to change the immunogenicity of synthetic peptides, and highlight the exquisite capacity of T-cell receptors to discriminate between structurally similar peptide sequences. Furthermore, this study highlights potential pitfalls associated with the use of synthetic peptides for the monitoring and modulating of human immune responses.     

CD8+ lymphocyte phenotype and cytokine production in long-term non-progressor and in progressor patients with HIV-1 infection

In most HIV-1-infected patients, clinical and immunological progression develops within a few years. Few infected people, termed long-term non-progressors (LTNP), remain healthy and immunologically stable for a long time. The factors governing the maintenance of this condition are not well known, but it is conceivable that CD8⁺ lymphocytes, cells that play a central role in controlling in vitro HIV replication, may have a part in vivo in this process. The aim of this study was to characterize the phenotypic profile and the cytokine production of CD8⁺ cells in a group of LTNP patients who had stable CD4⁺ cell counts (>500/mm³) for at least 7 years. Their CD8⁺ absolute numbers were similar to a control group composed of HIV-1⁺ patients who have a progressive decline of their CD4⁺ cell counts. However, our multiparameter immunofluorescence studies show that a clinical and immunologically stable condition is associated with the presence of a CD28⁺, CD95 strongly positive CD8⁺ population, while disease progression is marked by the CD28⁻CD95⁺CD8⁺ subset. Purified CD8⁺ cells from LTNP retain their ability to produce IL-2, interferon-gamma (IFN-γ) and, to a lesser degree, to produce IL-10 and IL-4. In contrast, CD8⁺ cells from progressors are unable to secrete IL-2 and IL-10. Although CD8⁺ cytokine profile does not fit with the proposed T helper (Th)1/Th2 switch in progressive HIV infection, LTNP CD8⁺ T cells maintain their capacity to produce IL-2 and IL-10 (Th0-like), a pattern very similar to that observed in normal HIV healthy controls. We suggest that CD8⁺ cells expressing CD28, CD95 and having a Th0-like profile may be considered to be associated with long-term survival.     

Programmed cell death 2 functions as a tumor suppressor in osteosarcoma

Objectives: To investigate the role of programmed cell death 2 (PDCD2) in osteosarcoma (OS), along with correlations between PDCD2 and CD4⁺/CD8⁺. Methods: Sprague-Dawley (SD) rats were randomly assigned to control group and OS group. The OS group rats were subjected to induce models of OS by transplantation with UMR106 cells. Peripheral blood was collected to test the percentages of the CD4⁺ and CD8⁺ cell subsets using flow cytometry (FCM). Western blotting was performed to determine the PDCD2 protein level. The correlations between PDCD2 and CD4⁺/CD8⁺ were analyzed by Pearson correlation coefficient. Besides, specific small interfering RNAs (siRNA) against PDCD2 and nonspecific (NS)-siRNA were transfected into UMR106 cells. Cell viability and invasive ability were determined after transfection. Results: CD4⁺ cells percentages were significantly decreased in the OS group, while CD8⁺ cells were significantly increased (P < 0.05). The PDCD2 protein levels were markedly lower than that in the control group (P < 0.05). Additionally, PDCD2 was positively correlated with CD4⁺ (R² = 0.66, P < 0.05), but was negatively correlated with CD8⁺ (R² = -0.94, P < 0.05). Moreover, the cell viability and invasion ability were significantly higher than that in the control group and the NS siRNA group after transfection with PDCD2 siRNA (P < 0.05). Conclusion: These results suggest that PDCD2 is involved in the pathogenesis of OS, and PDCD2 may play an important role in tumor suppression. These mechanisms might be related to immune response induced by CD4⁺ and CD8⁺ T cells.     

Failure of tumor-reactive lymph node cells to kill tumor in the presence of immune-suppressive CD34+ cells can be overcome with vitamin D3 treatment to diminish CD34+ cell levels

Growth of Lewis lung carcinoma (LLC-LN7) tumors results in an increase in CD34⁺ granulocyte-macrophage progenitor cells having natural suppressor (NS) activity. These CD34⁺ NS cells were capable of inhibiting the cytotoxic activity of tumor-reactive lymph node cells. In vivo studies showed that adoptive treatment of LLC-LN7 tumor-bearing mice with tumor-reactive lymph node cells plus IL-2 failed to reduce the development of metastases. Studies were conducted to determine if diminishing the levels of CD34⁺ NS cells would allow for improved anti-tumor effectiveness of the adoptively transferred cells. The suppressive activity of CD34⁺ cells toward the cytolytic activity of tumor-reactive lymph node cells could be blocked by in vitro culture of CD34⁺ cells with the differentiation-inducing hormone 1a,25-dihydroxyvitamin D₃. Similarly, treatment of LLC-LN7-bearing mice with vitamin D₃ alone diminished the levels of CD34⁺ NS cells within regional lymph nodes, spleens and tu mors. This treatment resulted in an increased immune reactivity to autologous tumor, as shown by the production of IFN-g by lymph node cells in response to the presence of LLC-LN7 cells. The extent of tumor metastasis in mice receiving vitamin D₃ treatment was also reduced. When tumor-reactive lymph node cells were adoptively transferred into these LLC-LN7-bearing mice that were receiving vitamin D₃ treatment, there resulted a pronounced synergistic reduction in tumor metastasis. The results of this study show that treatment of tumor bearers with vitamin D₃ to eliminate CD34⁺ NS cells improves the anti-tumor effectiveness of adoptively transferred tumor-reactive lymph node cells. © Rapid Science 1998     

Attenuation of Peripheral Regulatory T-Cell Suppression of Skin-Homing CD8+T Cells in Atopic Dermatitis

Purpose

Cutaneous lymphocyte-associated antigen (CLA)-expressing CD8⁺T cells have been known to play an important role in the pathogenesis of atopic dermatitis (AD). However, the mechanisms underlying the loss of self-tolerance remain unclear. Regulatory T cells (Tregs) play a key role in the development of homeostasis in the immune system. We, therefore, hypothesized that a reduced ability of Tregs to inhibit autologous CD8⁺CLA⁺T cells might be underlying mechanism in AD.

Materials and Methods

CD8⁺CLA⁺T cells and Tregs were obtained from the peripheral blood of AD patients and control volunteers. The frequencies of CD8⁺CLA⁺T cells were evaluated. The proliferative responses of CD8⁺CLA⁺T cells were assessed by flow cytometry, and the levels of transforming growth factor-β1 (TGF-β1) and interleukin-10 (IL-10) in culture supernatants were detected by enzyme-linked immunosorbent assay.

Results

Our results revealed higher frequency and increased expression of perforin and granzyme-B in peripheral CD8⁺CLA⁺T cells in AD, and lower inhibitory ability of Tregs on proliferation of CD8⁺CLA⁺T cells in AD. Meanwhile, the levels of TGF-β1 produced by Tregs were significantly lower in AD, and anti-TGF-β1 abolished such suppression.

Conclusion

The attenuated inhibitory ability of Tregs on hyper-activated autologous CD8⁺CLA⁺T cells, mediated by TGF-β1, plays an important role in the pathogenesis of AD.     

Gm40600 promotes CD4+ T‐cell responses by interacting with Ahnak

It is important to characterize novel proteins involved in T‐ and B‐cell responses. Our previous study demonstrated that a novel protein, Mus musculus Gm40600, reduced the proliferation of Mus musculus plasmablast (PB)‐like SP 2/0 cells and B‐cell responses induced in vitro by LPS. In the present study, we revealed that Gm40600 directly promoted CD4⁺ T‐cell responses to indirectly up‐regulate B‐cell responses. Importantly, we found that CD4⁺ T‐cell responses, including T‐cell activation and differentiation and cytokine production, were increased in Gm40600 transgenic (Tg) mice and were reduced in Gm40600 knockout (KO) mice. Finally, we demonstrated that Gm40600 promoted the Ahnak‐mediated calcium signalling pathway by interacting with Ahnak to maintain a cytoplasmic lateral location of Ahnak in CD4⁺ T cells. Collectively, our data suggest that Gm40600 promotes CD4⁺ T‐cell activation to up‐regulate the B‐cell response via interacting with Ahnak to promote the calcium signalling pathway. The results suggest that targeting Gm40600 may be a means to control CD4⁺ T‐cell‐related diseases.     

Anti-neutrophil monoclonal antibody therapy inhibits the development of adjuvant arthritis

The aim of this study was to determine the contribution of neutrophils to adjuvant arthritis (AA) by in vivo depletion of peripheral blood neutrophils. Specific anti-neutrophil MoAb, RP3 (10 mg), or a control antibody was given twice daily on days 8–11 after injection of Mycobacterium tuberculosis in inbred male Sprague-Dawley rats. RP3 treatment inhibited the neutrophil leukocytosis associated with AA (3.3 ± 0.6 × 10³/mm³versus 21.2 ± 6.9 × 10³/mm³; P < 0.001). On day 12, control animals exhibited severe arthritis as assessed by articular index (AI) (9.2 ± 1.3), increase in paw volume (149.3 ± 10.6%), and synovial fluid (SF) cell count (5.3 ± 0.5 × 10⁵). RP3 treatment significantly reduced AI (1 ± 0.1; P < 0.001), paw volume (103.6 ± 5.8%; P < 0.001) and SF cells (0.6 ± 0.1 × 10⁵; P < 0.001) without affecting cutaneous DTH (treated 0.6 ± 0.1 mm change in thickness, control 0.8 ± 0.2 mm; NS). Additional experiments demonstrated that CD4⁺ cell depletion but not decomplementation inhibited AA development and synovial neutrophil accumulation. Depletion of circulating neutrophils prevented joint inflammation and synovial leucocyte influx in AA, suggesting a pivotal role for neutrophils in the effector phase of AA. Inhibition of neutrophil accumulation by CD4⁺ cell depletion and not by decomplementation suggests that neutrophil accumulation in AA is T cell-dependent.     

Increased numbers of CD5+ B cells and T cell receptor (TCR) γδ+ T cells are associated with younger age of onset in rheumatoid arthritis (RA)

Patients presenting with RA before the age of 45 years (younger onset) are known to have more aggressive disease compared with patients presenting after the age of 65 years (older onset). Coordinated expansion of circulating CD5⁺ B cell and TCR γδ⁺ T cell levels has been reported in patients with RA. This study assesses the peripheral blood levels of these two cell types in RA patients with younger and older onset of disease. CD5⁺ B cell levels were significantly elevated in the younger onset RA group (26·6 ± 4·5%) compared with the older onset RA group (14·2 ± 1·2%; P <0·01). TCR γδ⁺ T cell levels were also significantly raised in the young patients (4·0 ± 0·9%) compared with elderly patients (1·6 ± 0·2%; P <0·01). T cell levels (CD3⁺) were similar in both groups (young 66·4 ± 3·3%; old 74·3 ± 3·4% (mean ± s.e.m.); NS). Total B cell levels (CD19⁺) were also similar in these groups (7·7 ± 0·7% versus 8·9 ± 1·8%; NS). A significant positive correlation was observed between the CD5⁻ B and TCR γδ⁺ T cell types in the patients (r = 0·72, P <0.05). Compared with age-matched normal controls, the younger onset patients had similar CD5⁺ B cell and TCR γδ⁺ T cell levels to the elderly controls (CD5⁺ B cells 30·2 ± 3·0%; TCR γδ⁺ T cells 3·0 ± 0·8%). Conversely, older onset RA patients had CD5⁺ B cell levels similar to the young controls (12·3 ± 1·9%). Spontaneous in vitro synthesis of immunoglobulins (IgM, IgA and IgG) and rheumatoid factors (IgM and IgA isotypes) were not significantly different in both patient groups. The coordinate expansion of circulating CD5⁺ B cells and γδ⁺ T cells seen in patients with RA presenting before 45 years of age and not after 65 years of age may suggest a potential role for these cells in more aggressive disease states.