Effect of LAG3 deficiency on natural killer cell function and hepatic fibrosis in mice infected with Echinococcus multilocularis / 中国血吸虫病防治杂志

Objective To investigate the effect of LAG-3 deficiency (LAG3-/-) on natural killer (NK) cell function and hepatic fibrosis in mice infected with Echinococcus multilocularis. Methods C57BL/6 mice, each weighing (20 ± 2) g, were divided into the LAG3-/- and wild type (WT) groups, and each mouse in both groups was inoculated with 3 000 E. multilocularis protoscoleces via the hepatic portal vein. Mouse liver and spleen specimens were collected 12 weeks post-infection, sectioned and stained with sirius red, and the hepatic lesions and fibrosis were observed. Mouse hepatic and splenic lymphocytes were isolated, and flow cytometry was performed to detect the proportions of hepatic and splenic NK cells, the expression of CD44, CD25 and CD69 molecules on NK cell surface, and the secretion of interferon γ (IFN-γ), tumor necrosis factor α (TNF-α), interleukin (IL)-4, IL-10 and IL-17A. Results Sirius red staining showed widening of inflammatory cell bands and hyperplasia of fibrotic connective tissues around mouse hepatic lesions, as well as increased deposition of collagen fibers in the LAG3-/-group relative to the WT group. Flow cytometry revealed lower proportions of mouse hepatic (6.29% ± 1.06% vs. 11.91% ± 1.85%, P < 0.000 1) and splenic NK cells (4.44% ± 1.22% vs. 5.85% ± 1.10%, P > 0.05) in the LAG3-/- group than in the WT group, and the mean fluorescence intensity of CD44 was higher on the surface of mouse hepatic NK cells in the LAG3-/- group than in the WT group (t = −3.234, P < 0.01), while no significant differences were found in the mean fluorescence intensity of CD25 or CD69 on the surface of mouse hepaticNK cells between the LAG3-/- and WT groups (both P values > 0.05). There were significant differences between the LAG3-/- and WT groups in terms of the percentages of IFN-γ (t = −0.723, P > 0.05), TNF-α (t = −0.659, P > 0.05), IL-4 (t = −0.263, P > 0.05), IL-10 (t = −0.455, P > 0.05) or IL-17A secreted by mouse hepatic NK cells (t = 0.091, P > 0.05), and the percentage of IFN-γ secreted by mouse splenic NK cells was higher in the LAG3-/- group than in the WT group (58.40% ± 1.64% vs. 50.40% ± 4.13%; t = −4.042, P < 0.01); however, there were no significant differences between the two groups in terms of the proportions of TNF-α (t = −1.902, P > 0.05), IL-4 (t = −1.333, P > 0.05), IL-10 (t = −1.356, P > 0.05) or IL-17A secreted by mouse splenic NK cells (t = 0.529, P > 0.05). Conclusions During the course of E. multilocularis infections, LAG3-/- promotes high-level secretion of IFN-γ by splenic NK cells, which may participate in the reversal the immune function of NK cells, resulting in aggravation of hepatic fibrosis.

Self-assembling, pH-responsive nanoflowers for inhibiting PAD4 and neutrophil extracellular trap formation and improving the tumor immune microenvironment

Self-assembling carrier-free nanodrugs are attractive agents because they accumulate at tumor by an enhanced permeability and retention (EPR) effect without introduction of inactive substances, and some nanodrugs can alter the immune environment. We synthesized a peptidyl arginine deiminase 4 (PAD4) molecular inhibitor, ZD-E-1M. It could self-assembled into nanodrug ZD-E-1. Using confocal laser scanning microscopy, we observed its cellular colocalization, PAD4 activity and neutrophil extracellular traps (NETs) formation. The populations of immune cells and expression of immune-related proteins were determined by single-cell mass cytometry. ZD-E-1 formed nanoflowers in an acidic environment, whereas it formed nanospheres at pH 7.4. Accumulation of ZD-E-1 at tumor was pH-responsive because of its pH-dependent differences in the size and shape. It could enter the nucleus and bind to PAD4 to prolong the intracellular retention time. In mice, ZD-E-1 inhibited tumor growth and metastasis by inhibiting PAD4 activity and NETs formation. Besides, ZD-E-1 could regulate the ratio of immune cells in LLC tumor-bearing mice. Immunosuppressive proteins like LAG3 were suppressed, while IFN-γ and TNF-α as stimulators of tumor immune response were upregulated. Overall, ZD-E-1 is a self-assembling carrier-free nanodrug that responds to pH, inhibits PAD4 activity, blocks neutrophil extracellular traps formation, and improves the tumor immune microenvironment.

Research advances in biological function of lymphocyte activation gene-3 (LAG-3) molecule and clinical application of antibody drugs targeting LAG-3 / 中国药理学与毒理学杂志

Lymphocyte activation gene-3 (LAG-3, CD223) is a class of immunosuppressive receptors, mainly expressed on the cell surface of activated T and natural killer (NK) cells. As with programmed death-1 (PD-1), T cell immunoglobulin domain and mucin domain-3 (TIM-3) and other immune check-points, the expression of LAG-3 in activated T cells is upregulated to prevent the occurrence of autoimmune diseases. In the tumor microenvironment, persistent antigenic stimulation can induce T cells to overexpress LAG-3 and other suppressor molecules, causing local immune suppression in the tumor microenvironment. However, the mechanism by which LAG-3 inhibits downstream signals of T-activation or interacts with other immunosuppressive molecules is still unknown. Preliminary clinical data has shown that anti-LAG-3 and anti-PD-1 antibodies possess synergistic effect on the treatment of tumors. Moreover, LAG-3 has different intracellular domains which are completely different from those of any other immunological negative regulatory molecules, suggesting that LAG-3 might have a unique molecular mechanism and prospect of application. Currently, there are at least 7 kinds of antibody drugs targeting LAG-3 and one kind of LAG-3-Fc fusion protein in clinical research, which indicates that anti-LAG-3 targeted drugs have a broad prospect of clinical application.

Lymphocyte-Activation Gene-3 Expression and Prognostic Value in Neoadjuvant-Treated Triple-Negative Breast Cancer / 한국유방암학회지

PURPOSE: In this study, we aimed to evaluate lymphocyte-activation gene-3 (LAG-3) expression and its prognostic value in neoadjuvant-treated triple-negative breast cancer (TNBC). METHODS: LAG-3, programmed death-1 (PD-1), programmed death ligand-1 (PD-L1), and CD8⁺ tumor-infiltrating lymphocyte (TILs) levels were examined using immunohistochemistry in 148 preand 114 post-neoadjuvant chemotherapy (NACT) specimens of human TNBC tissue. Correlations between expression levels and clinicopathological features were analyzed. Prognostic values for combined detection in TNBC following NACT were evaluated. RESULTS: In pre-NACT specimens, LAG-3 expression showed a significant association with pathological complete response (pCR, p=0.038) and was correlated with PD-1 (p<0.001) and PD-L1 (p=0.008). In post-NACT specimens, high expression of LAG-3 showed significant effects on nodal status (p=0.023) and PD-1 (p<0.001). The expression of immune markers on TILs significantly increased following NACT. Multivariate analysis indicated that only nodal status (odds ratio [OR], 0.226; 95% confidence interval [CI], 0.079–0.644; p=0.005) and high quantities of CD8⁺TILs (OR, 3.186; 95% CI, 1.314–7.721; p=0.010) are independent predictors of pCR. Nodal status (hazard ratio [HR], 2.666; 95% CI, 1.271–5.594; p=0.010), CD8⁺TILs (HR, 0.313; 95% CI, 0.139–0.705; p=0.005), and the LAG-3-high/PD-L1-high group (HR, 2.829; 95% CI, 1.050–7.623; p=0.040) provided prognostic values for patients with TNBC following NACT. CONCLUSION: CD8+TILs were sensitive predictive markers in response to NACT. High expression of LAG-3 in residual tissues, especially in combination with PD-L1, was associated with poor prognosis.

Effect of different stimulants on the LAG3 expression and function of spleen lymphocytes in mice / 中国生化药物杂志

Objective To investigate the effect of different stimulants on the LAG3 expression and function of spleen lymphocytes in mice. Methods The spleen lymphocytes from mice were isolated by density centrifugation.The LAG3 expressions in T cell subsets after exposure to conA, PMA, PHA or anti-CD3/28 antibodies for 24 h or 72 h were analyzed by Flow cytometry.The IFN-γsecretions of conditional medium were detected by ELISA kit.The proliferation of lymphocytes was examined by MTT analysis.Results Treatment with conA for 24 h or 72 h dose-dependently increased LAG3 +CD3 +and LAG3 +CD4 +CD3 +T cell percentages.Similarly, an exposure of anti-CD3/28 antibodies for 72 h significantly increased LAG3 +CD3 +and LAG3 +CD4 +CD3 + T cell percentages.Meanwhile, conA and anti-CD3/28 antibodies increased the IFN-γsecretion of lymphocytes in a time-dependent manner.Furthermore, Treatment with conA, PMA, PHA or anti-CD3/28 antibodies for 72 h could enhance the proliferation of lymphocyte. Conclusion conA and anti-CD3/28 antibodies are effective activators of T cells, and both of them could promote the expression of LAG3 and IFN-γsecretion of lymphocytes.