Hepatitis B virus (HBV)-specific CD8⁺ T cells play a central role in controlling HBV infection; however, their function is impaired during chronic HBV infection, manifesting as a state of dysfunction. Recent studies have revealed that CD8⁺ T cell dysfunction in chronic HBV infection differs from the classical exhaustion observed in other viral infections or tumors. In 2024, several pivotal studies further elucidated novel mechanisms underlying CD8⁺ T cell dysfunction in chronic HBV infection and identified new therapeutic targets, including 4-1BB and transforming growth factor-beta (TGF-β). This review, while elucidating the dysfunction of CD8⁺ T cells in chronic HBV infection and its underlying mechanisms, focuses on summarizing the key findings from these latest studies and explores their translational value and clinical significance.
Humans ; Hepatitis B, Chronic/virology* ; CD8-Positive T-Lymphocytes/immunology* ; Hepatitis B virus/physiology* ; Animals ; Transforming Growth Factor beta/immunology*

Antibodies, Neutralizing ; Antibodies, Viral/isolation & purification* ; B-Lymphocytes/virology* ; COVID-19/virology* ; Humans ; Immunity/genetics* ; RNA, Viral/immunology* ; SARS-CoV-2/pathogenicity* ; Single-Cell Analysis

Progressive multifocal leukoencephalopathy (PML) is a rare and lethal central nervous demyelinating disease caused by JC polyomavirus (JCV), particularly in patients with impaired immune system. The variation of JCV plays an important role in the pathogenesis of PML, including the recombination of non-coding regulatory region (NCCR), which is closely related to binding sites of transcription factors and affect the level of gene transcription. Nucleotide mutations in VP1 region determine the antigenicity and receptor specificity of JCV, play an important role in cell adsorption, immune-mediation and pathogenicity. In addition, immune cells are also involved in the pathogenesis of PML. T lymphocytes can recognize virus antigens, clear JCV, which are directly related to the prognosis of PML. B lymphocytes can serve as latent sites of JCV, and participate in viral transmission, replication, and coordination of the expression of transcription factors. This paper summarizes the roles of JCV variation and immune cells in pathogenesis of PML.
B-Lymphocytes ; immunology ; virology ; Capsid Proteins ; genetics ; immunology ; Humans ; JC Virus ; immunology ; Leukoencephalopathy, Progressive Multifocal ; pathology ; virology ; Mutation ; T-Lymphocytes ; immunology ; virology

PURPOSE: Acute hepatitis A (AHA) and acute hepatitis B (AHB) are caused by an acute infection of the hepatitis A virus and the hepatitis B virus, respectively. In both AHA and AHB, liver injury is known to be mediated by immune cells and cytokines. In this study, we measured serum levels of various cytokines and T-cell cytotoxic proteins in patients with AHA or AHB to identify liver injury-associated cytokines. MATERIALS AND METHODS: Forty-six patients with AHA, 16 patients with AHB, and 14 healthy adults were enrolled in the study. Serum levels of 17 cytokines and T-cell cytotoxic proteins were measured by enzyme-linked immunosorbent assays or cytometric bead arrays and analyzed for correlation with serum alanine aminotransferase (ALT) levels. RESULTS: Interleukin (IL)-18, IL-8, CXCL9, and CXCL10 were significantly elevated in both AHA and AHB. IL-6, IL-22, granzyme B, and soluble Fas ligand (sFasL) were elevated in AHA but not in AHB. In both AHA and AHB, the serum level of CXCL10 significantly correlated with the peak ALT level. Additionally, the serum level of granzyme B in AHA and the serum level of sFasL in AHB correlated with the peak ALT level. CONCLUSION: We identified cytokines and T-cell cytotoxic proteins associated with liver injury in AHA and AHB. These findings deepen the existing understanding of immunological mechanisms responsible for liver injury in acute viral hepatitis.
Acute Disease ; Adult ; Alanine Transaminase/blood ; Biomarkers/blood ; Cytokines/*blood ; Enzyme-Linked Immunosorbent Assay ; Fas Ligand Protein/blood ; Female ; Hepatitis A/blood/virology ; Hepatitis A virus/*genetics/immunology ; Hepatitis B/blood/virology ; Hepatitis B virus/*genetics/immunology ; Humans ; Interleukin-6/blood ; Interleukin-8/blood ; Interleukins/blood ; Liver Failure/immunology/metabolism/*pathology ; Male ; Middle Aged ; T-Lymphocytes, Cytotoxic/immunology/*metabolism

Currently, killed-virus and modified-live porcine reproductive and respiratory syndrome virus (PRRSV) vaccines are used to control porcine reproductive and respiratory syndrome. However, both types of vaccines have inherent drawbacks; accordingly, the development of novel PRRSV vaccines is urgently needed. Previous studies have suggested that yeast possesses adjuvant activities, and it has been used as an expression vehicle to elicit immune responses to foreign antigens. In this report, recombinant Kluyveromyces lactis expressing GP5 of HP-PRRSV (Yeast-GP5) was generated and immune responses to this construct were analyzed in mice. Intestinal mucosal PRRSV-specific sIgA antibody and higher levels of IFN-gamma in spleen CD4+ and CD8+ T cells were induced by oral administration of Yeast-GP5. Additionally, Yeast-GP5 administered subcutaneously evoked vigorous cell-mediated immunity, and PRRSV-specific lymphocyte proliferation and IFN-gamma secretion were detected in the splenocytes of mice. These results suggest that Yeast-GP5 has the potential for use as a vaccine for PRRSV in the future.
Administration, Oral ; Animals ; Antibodies, Viral/*immunology ; B-Lymphocytes/immunology/virology ; Enzyme-Linked Immunosorbent Assay ; *Immunity, Cellular ; *Immunity, Mucosal ; Injections, Subcutaneous ; Kluyveromyces/genetics ; Mice ; Mice, Inbred BALB C ; Porcine respiratory and reproductive syndrome virus/*immunology ; Recombinant Proteins/genetics/immunology ; T-Lymphocytes/immunology/virology ; Viral Envelope Proteins/*genetics/*immunology ; Viral Vaccines/administration & dosage/*pharmacology

<b>OBJECTIVEb>To investigate the effect and clinical significance of glucocorticoid on CD4+CD25+ regulatory T cells (Tregs) in patients with hepatitis B virus (HBV)-related pre-liver failure.

<b>METHODSb>The subjects of this study included 78 patients with pre-liver failure induced by HBV (cases) and 24 healthy individuals (controls). Among the 78 cases, 42 received glucocorticoid treatment and 36 did not. Between-group differences in Tregs (in peripheral blood) were evaluated by flow cytometry and statistical analysis.

<b>RESULTSb>Two weeks of glucocorticoid treatment led to an increase in Treg level compared to baseline (before therapy: 2.76 ± 0.73 vs. 3.88 ± 1.60). In addition, after the two weeks of glucocorticoid treatment, the Treg level of improved patients was significantly higher than that measured at baseline (before therapy: 2.70 ± 0.77 vs 3.97 ± 1.59, P < 0.05).

<b>CONCLUSIONb>Glucocorticoids up-regulate the expression of Treg cells, which may contribute to the immunological mechanism that protects pre-liver failure patients from deterioration of their condition. Careful inspection and monitoring of Treg levels may help improve prognosis of these patients.

Adult ; Case-Control Studies ; Female ; Glucocorticoids ; therapeutic use ; Hepatitis B virus ; Hepatitis B, Chronic ; drug therapy ; immunology ; Humans ; Liver Failure ; immunology ; virology ; Male ; Middle Aged ; T-Lymphocytes, Regulatory ; cytology ; immunology ; Young Adult

This study was aimed to explore the method for induction and expansion of EB virus specific cytotoxic T lymphocytes (EBV-CTL) in vitro, and to detect their killing effect. Peripheral blood mononuclear cells (PBMNC) were collected from 6 EBV seropositive healthy donors, and EBV-transformed B lymphoblastoid cells (BLCL)were used as the antigen-presenting cells and antigen stimulant which was irradiated by 40 Gy (60)Co irradiator. The autologous PBMNC and irradiated BLCL were cultured to induce and expand the EBV-CTL, and the immunophenotype was identified by the flow cytometry. The killing effect of the EBV-CTL against the autologous BLCL (autoBLCL), the autologous PHA cultured B lymphoblastoid cells( PHA-BLCL), the allogeneic BLCL (alloBLCL) and the K562 cells were measured with LDH release assay under different effector-to-target ratio. The results showed that the 6 cell lines of EBV-CTL were induced and expanded from the EBV seropositive healthy donors, the overall increase in cell numbers varied from 18.6 to 55.0 times. After 10 stimulations, the specific killing efficiency of the EBV-CTL for the autoBLCL were 59.4%, 43.2% and 29.0% under the effector-to-target ratio of 20: 1, 10: 1 and 5: 1. The nonspecific killing efficiency for the PHA-blast, alloBLCL and K562 cells were 7.1%, 9.4% and 10.3% (P < 0.05) under the 20: 1 ratio; 6.6%, 8.3% and 8.1% (P < 0.05) under 10: 1; 5.4%, 7.3% and 6.3% (P < 0.05) under 5: 1, respectively. It is concluded that the EBV-CTL can be successfully induced and expanded ex vivo for specific killing of HLA matched BLCL and may become a potential treatment for EBV related post-transplant lymphoproliferative disorders.
B-Lymphocytes ; immunology ; Cell Line, Transformed ; Herpesvirus 4, Human ; immunology ; Humans ; K562 Cells ; Leukocytes, Mononuclear ; immunology ; virology ; T-Lymphocytes, Cytotoxic ; cytology ; immunology ; virology

Hepatitis B virus ; Hepatitis B, Chronic ; immunology ; virology ; Humans ; T-Lymphocytes ; immunology

<b>OBJECTIVEb>To investigate the effect of HBV antigens and pathological mechanism of chronic HBV infection by analyzing the cellular immune function of peripheral blood mononuclear cells (PBMCs) from HBsAg carriers.

<b>METHODSb>PBMCs were prepared from individuals with chronic asymptomatic HBV infection and cultured in the presence of different antigens and/ or cytokines. The levels of cytokines in culture supernatants were detected by ELISA method. The phenotype of the cells was detected by FACS.

<b>RESULTSb>The levels of IFN y secreted by PBMCs from HBsAg carriers were (48.3+/-19.8) pg/ml, significantly lower than that from healthy controls (t = 3.023, P less than 0.05); The IFN y produced by PBMCs from HBeAg positive patients due to HBsAg and HBcAg stimulation were (50.4+/-51.6) pg/ml and (63.2+/-36.9) pg/ml, significantly lower than that of HBeAg negative patients (t = 2.468 and 3.184, P less than 0.05, respectively). The IL-12p70 secreted by PBMCs from HBeAg positive patients was also significantly lower than that of HBeAg negative patients (P less than 0.05); Exogenous IL-12 promoted significantly PBMCs to secrete IFN y (P less than 0.01) and IL-12 combined with HBV antigens activated CD8+CD45RA+CCR7+ and CD8+CD45RA-CD62L+ cells. IL-12 secreted by PBMCs decreased in HBeAg positive patients, which may be the crucial reason of viral persistence in chronic HBV carriers. Exogenous IL-12 combined with specific HBV antigen could promote the central memory CD8+ T cells to produce IFN y.

Adolescent ; Adult ; Carrier State ; blood ; immunology ; virology ; Case-Control Studies ; Hepatitis B ; blood ; immunology ; Hepatitis B Antigens ; blood ; Hepatitis B virus ; immunology ; Humans ; Interferon-gamma ; blood ; Interleukin-12 ; blood ; immunology ; Leukocytes, Mononuclear ; immunology ; T-Lymphocytes ; immunology ; Young Adult

<b>OBJECTIVEb>To investigate the expressions of perforin (PF), granzyme B (GrB), granulysin (GNLY), TNF-alpha and IFN-gamma in peripheral CD8+ T lymphocytes and their correlation to infection status in patients with chronic hepatitis B (CHB).

<b>METHODSb>ALT, AST, TB and HBV DNA copy were detected to evaluate the infection status in CHB patients, with healthy volunteers serving as the control group. According to the infection status, the CHB patients were divided into 4 groups, namely normal hepatic function and high HBV DNA level group, normal hepatic function and low HBV DNA level group, abnormal hepatic function and high HBV DNA level group and abnormal hepatic function and low HBV DNA level group. The expressions of some immune effector molecules in CD8+T cells were detected by flow cytometry, and the correlations between these immune effector molecules and the infection status were analyzed.

<b>RESULTSb>The expressions of GrB, TNF-alpha and IFN-gamma in normal hepatic function and low HBV DNA level group were significantly higher than those in abnormal hepatic function and high HBV DNA level group (P<0.05). The expression of IFN-gamma in normal hepatic function and high HBV DNA level group was significantly higher than that in abnormal hepatic function and high HBV DNA level group (P<0.05). The expressions of PF and GNLY were similar among all the 4 groups. Positive correlations were noted between GrB, PF, GNLY, TNF-alpha and IFN-gamma.

<b>CONCLUSIONb>GrB, TNF-alpha and IFN-gamma in peripheral CD8+ T cells are inversely correlated to hepatic dysfunction and HBV DNA level in CHB patients.

Adult ; CD8-Positive T-Lymphocytes ; immunology ; metabolism ; Case-Control Studies ; DNA, Viral ; blood ; Female ; Granzymes ; blood ; Hepatitis B, Chronic ; blood ; immunology ; Humans ; Interferon-gamma ; blood ; Liver ; physiopathology ; virology ; Male ; Middle Aged ; Perforin ; blood ; Tumor Necrosis Factor-alpha ; blood ; Young Adult