BACKGROUNDThe mechanism of chronic immune activation and impairment of HIV-specific immune responses during chronic infection is not fully understood. However, it is known that high immune activation leads to more rapid progression to AIDS. We hypothesize that CD4(+) T cell-mediated viral antigen presentation contributes to this pathologic immune activation in HIV-infected individuals.

METHODSHIV-specific T cells, responding to noninfectious HIV-1 virions as antigen, were measured by flow cytometric assays. These experimental conditions reflect the in vivo condition where noninfectious HIV-1 represents more than 99% of the antigens.

RESULTSCD4(+) T cells purified from HIV-infected individuals were capable of cross presenting exogenous noninfectious HIV-1 virions to HIV-1-specific CD8(+) T cells. Cross presentation required the entry of HIV-1 to CD4(+) T cells and antigen translocation from endoplasmic reticulum to the Golgi complex. Blocking CD4(+) mediated activation of HIV-specific CD8(+) T cells and redirecting the viral antigens to antigen presenting cells improved HIV-specific T cell responses.

CONCLUSIONSOne possible cause of chronic immune activation and impairment of HIV-1 specific T cell responses is represented by HIV-1 harboring CD4(+) T cells cross presenting HIV-1 antigen to activate CD8(+) T cells. This new mechanism provides the first evidence that cross presentation of noninfectious HIV-1 virions play a role in the immunopathogenesis of HIV-1 infection.

Adult ; Antigen Presentation ; CD4-Positive T-Lymphocytes ; immunology ; virology ; CD8-Positive T-Lymphocytes ; immunology ; HIV-1 ; immunology ; Humans ; Lymphocyte Activation ; Male ; Virion ; immunology

OBJECTIVETo investigate the relationship between coxsackievirus infection and type 1 diabetes mellitus (T1DM), and observe the changes of T lymphocyte subsets in the development of T1DM.

METHODSWe detected Coxsackievirus RNA by reverse transcription PCR, and measured the change in T-lymphocyte subsets by flow cytometry in 22 cases of newly diagnosed T1DM (group I), 30 patients with diabetes for some time (group II), and 30 healthy subjects (group III).

RESULTSThe positivity rate of coxsackie virus RNA in groups I, II, and III was 55.55%, 23.33%, and 6.67%, respectively, showing a significant difference among the 3 groups (P<0.01). Patients with upper respiratory tract infection had a higher positivity rate for coxsackie virus RNA than those without upper respiratory tract infection in group I (P<0.05). Compared with the control group, the percentage of CD3, CD4 and CD4/CD8 ratio decreased significantly in groups I and II (P<0.01 or P<0.05). CD3, CD4 and CD4/CD8 tended to increase in group II in comparison with group I, and there was an significant difference in CD3 and CD4 between the two groups (P<0.01 or P<0.05). Compared with the control group and CVBRNA-negative group, CVBRNA-positive group showed significantly lowered CD3, CD4, CD8 and CD4/CD8 (P<0.01 or P<0.05).

CONCLUSIONThe occurrence and development of type 1 diabetes is closely related to coxsackie virus infection, and the changes in T lymphocyte subsets serves as a probable mechanism of its pathogenicity.

Adolescent ; Adult ; CD4-CD8 Ratio ; CD4-Positive T-Lymphocytes ; immunology ; CD8-Positive T-Lymphocytes ; immunology ; Coxsackievirus Infections ; complications ; immunology ; Diabetes Mellitus, Type 1 ; complications ; virology ; Female ; Humans ; Lymphocyte Count ; Male ; T-Lymphocyte Subsets ; immunology ; Young Adult

OBJECTIVETo study the characteristics of the peripheral blood lymphocyte subsets in pediatric patients with chronic active EBV (CAEBV) infection.

METHODFlow cytometry was used to detect the peripheral blood NK, B, T lymphocyte subsets and the functional, regulatory, naïve, memory and activatory subsets of T lymphocytes in 10 pediatric patients with CAEBV infection, 13 pediatric patients with acute Epstein-Barr virus infection (AEBV) and 12 healthy children in our hospital between March 2004 and April 2008.

RESULTCompared with AEBV group, the number of white blood cells [3325 x 10(6)/L (median, just the same as the following)], lymphocytes (1078 x 10(6)/L), NK cells (68 x 10(6)/L), B cells (84 x 10(6)/L), total T cells (684 x 10(6)/L), CD4+ T cells (406 x 10(6)/L) and CD8+ T cells (295 x 10(6)/L) in CAEBV patients were lower (P<0.05). The functional subset of the CD4+ T cells in CAEBV group (94.5%) was lower than those of the healthy control group (98.7%) (P<0.05), but was still higher than those of AEBV group (74.0%) (P<0.05). While the functional subset of the CD8+ T cells in CAEBV (40.7%) was not dramatically different from the healthy control group (48.3%), but was still higher than that of AEBV group (21.0%) (P<0.05). Although the regulatory subset in CAEBV group (5.0%) was higher than the health control group (4.6%) (P<0.05), but lower than AEBV group (5.8%) (P<0.05). In CAEBV, the proportion of CD4+/CD8+ naïve T cells (32.3%/37.5%) was lower than that of normal group (58.3%/56.6%) (P<0.05), but the proportion of CD4+/CD8+ effective memory T cells in CAEBV group (23.9%/15.1%) was lower than that in AEBV group (36.5%/69.8%) (P<0.05), while the proportion of CD8+ fake naïve T cells in CAEBV (17.5%) was higher than the other 2 groups (P<0.05). The CD8+ activatory subset in CAEBV group (84.4%/34.0%) was higher than that of the healthy control group (44.1%/16.7%) (P<0.05), but still lower than AEBV group (96%/95%) (P<0.05).

CONCLUSIONThere is an imbalance in lymphocyte subsets and disturbance in cellular immunity in CAEBV patients, which may be associated with EBV chronic active infection. Detecting the peripheral haematologic parameters and lymphocyte subsets may be helpful in the diagnosis and the differential diagnosis of CAEBV.

Adolescent ; CD4-CD8 Ratio ; CD4-Positive T-Lymphocytes ; CD8-Positive T-Lymphocytes ; Case-Control Studies ; Child ; Epstein-Barr Virus Infections ; blood ; immunology ; virology ; Female ; Flow Cytometry ; Herpesvirus 4, Human ; Humans ; Killer Cells, Natural ; Lymphocyte Subsets ; immunology ; Male

OBJECTIVETo determine the complementary determining region 3 (CDR3) length diversity of T cell receptor Vbeta repertoires of CD8+ T lymphocytes and to explore its association with viral load in individuals with HIV-1 infection.

METHODSSeparation of CD8+ T cells from peripheral blood mononuclear cells (PBMCs) was carried out by using immunomagnetic beads coated with anti-CD8 antibody. Total RNAs from the purified CD8+ T lymphocytes were isolated and used to perform polymerase chain reaction (PCR) amplifications in CDR3 of 22 T cell receptor (TCR) gene families. CDR3 diversity and its association with viral load in individuals with HIV-1 infection were analyzed.

RESULTSAn average diversity for all CDR3 profiles in CD8+ T cells from 9 HIV-infected individuals was significantly different as compared to 7 age-matched healthy donors (P<0.05) with the HIV-infected individuals losing diversity in the CDR3 profiles. There was positive correlation between changes in TCR CDR3 diversity and viral load (r=0.771, P<0.05). The changes in CDR3 length diversity of Vbeta families in HIV-infected individuals, particular in Vbeta2, Vbeta4, Vbeta5, Vbeta17, Vbeta20, Vbeta21, Vbeta23, Vbeta24, were statistically different from the healthy controls.

CONCLUSIONHIV-1 infection might induce the loss of TCR Vbeta repertoire diversity and disrupt the CDR3 distributions within CD8+ T cells. There should be positive correlation between changes in TCR CDR3 diversity and the viral load in HIV-1 infected patients.

CD8-Positive T-Lymphocytes ; immunology ; HIV Infections ; genetics ; virology ; HIV-1 ; immunology ; Humans ; Polymorphism, Genetic ; Receptors, Antigen, T-Cell ; genetics ; Viral Load

Hepatocytes are the primary targets of the hepatitis C virus (HCV). While immunosuppressive roles of HCV core protein have been found in several studies, it remains uncertain whether core protein expressed in hepatocytes rather than in immune cells affects the CD8+ T cell response. In order to transduce genes selectively into hepatocytes, we developed a baculoviral vector system that enabled primary hepatocytes to express a target epitope for CD8+ T cells, derived from ovalbumin (OVA), with or without HCV core protein. Culture of OVA-specific CD8+ T cells with hepatocytes infected with these baculoviral vectors revealed that core protein has no effect on proliferation or apoptosis of CD8+ T cells. Our results suggest that HCV core protein does not exert its suppressive role on the CD8+ T cell immune response through expression in hepatocytes.
Viral Core Proteins/*metabolism ; Ovalbumin/genetics/immunology ; Mice ; Hepatocytes/cytology/*virology ; Green Fluorescent Proteins/genetics ; Genetic Vectors ; Cell Proliferation ; CD8-Positive T-Lymphocytes/*immunology ; Baculoviridae/genetics ; Apoptosis ; Animals

Infectious mononucleosis due to Epstein-Barr virus (EBV) infection sometimes causes acute hepatitis, which is usually self-limiting with mildly elevated transaminases, but rarely with jaundice. Primary EBV infection in children is usually asymptomatic, but in a small number of healthy individuals, typically young adults, EBV infection results in a clinical syndrome of infectious mononucleosis with hepatitis, with typical symptoms of fever, pharyngitis, lymphadenopathy, and hepatosplenomegaly. EBV is rather uncommonly confirmed as an etiologic agent of acute hepatitis in adults. Here, we report two cases: the first case with acute hepatitis secondary to infectious mononucleosis and a second case, with acute hepatitis secondary to infectious mononucleosis concomitantly infected with hepatitis A. Both cases involved young adults presenting with fever, pharyngitis, lymphadenopathy, hepatosplenomegaly, and atypical lymphocytosis confirmed by serologic tests, liver biopsy and electron microscopic study.
Acute Disease ; Adult ; CD8-Positive T-Lymphocytes/virology ; Female ; Hepatitis/*etiology/pathology ; Humans ; Infectious Mononucleosis/*complications ; Liver/pathology/ultrastructure ; Male ; Young Adult

BACKGROUNDS/AIMS: Hepatitis B virus(HBV) specific cytotoxic T lymphocyte (CTL) response is believed to play a major role in virus control and liver damage in chronic hepatitis B(CHB). We performed this study to evaluate whether HBV specific CTL could be visualized directly by tetrameric HLA-A2/core 18-27 complex(T c18-27) in the peripheral blood and liver of patients with CHB. On the basis of our results we clarified patients intrahepatic compartmentalization and correlation with HBV specific CTL and viral replication or liver damage. METHODS: We stained peripheral blood mononuclear cells of 33 HLA-A2 + and 8 HLA-A2 patients with CHB with cychrome conjugated anti-CD8 mAb and phycoerythrin conjugated T c18-27. Among these we analysed intrahepatic lymphocyte of 11 HLA-A2 + patients. We compared the frequency of T c18-27 specific CD8+ cells with serum HBV-DNA levels or alanine aminotransferase(ALT) levels. RESULTS: The frequency of circulating T c18-27 specific CD8+ cell was higher(9-101 cells per 50,000 CD8+ cells) than background level in 14 among 33 patients. The frequency of intrahepatic T c18-27 specific CD8+ cells was 12-2100 cells per 50,000 CD8+ cells in 8 out of 11 patients whose liver was obtained This was 17.4-150 times higher than circulating T c18-27 specific CD8+ cells. The frequency of circulating T c18-27 specific CD8+ cells was increased in 10 out of 18 patients with serum HBV DNA level <0.5 pg/mL and ALT < 40 IU/L. It was increased in just 4 out of 15 patients with HBV DNA level > 800 pg/mL and ALT >70 IU/L. The frequency of intrahepatic T c18-27 CTL tended to be lower in high levels of serum HBV DNA and was not correlated with liver inflammation. CONCLUSION: This study provess that if HBV-specific CTLs are barely detectable in the peripheral blood of CHB, much more HBV-specific CTLs are in the liver and most HBV-specific CTLs are infiltrated in the liver. Also, in the presence of an effective HBV specific CD8 response the inhibition of viral replication can be independent of liver damage.
CD8-Positive T-Lymphocytes/immunology ; DNA, Viral/analysis ; English Abstract ; HLA-A2 Antigen/analysis/*immunology ; Hepatitis B Virus/genetics/*immunology ; Hepatitis B, Chronic/*immunology/virology ; Human ; T-Lymphocytes, Cytotoxic/*immunology ; Viral Core Proteins/*immunology

OBJECTIVETo investigate the pathogenesis and immunogenicity of H9N2 influenza virus A/Guangzhou/333/99 (a reassortant of G1 and G9 viruses isolated from a female patient in 1999) in a mouse model of infection.

METHODSMice were infected with increasing virus titers. Viral load in the lungs and trachea was determined by EID50 assay. Pulmonary histopathology was assessed by hematoxylin-eosin staining. Anti-HI antibody titers and T-cell responses to viral HA were determined by ELISPOT and confirmed by flow cytometry.

RESULTSMice presented a mild syndrome after intranasal infection with A/Guangzhou/333/99 (H9N2) influenza virus. Virus was detected in the trachea and lungs of mice harvested on days 3, 6, and 9 post-infection. A T-cell response to viral HA was detected on day 6 and H9 HA-specific CD(4+) T-cells predominated. Seroconversion was detected after 14 days and antibody persisted for at least 28 weeks.

CONCLUSIONOur results suggest that H9N2 (A/Guangzhou/333/99) can replicate in the murine respiratory tract without prior adaptation, and both humoral and cell-mediated immunity play an important role in the immune response.

Animals ; CD4-Positive T-Lymphocytes ; immunology ; CD8-Positive T-Lymphocytes ; immunology ; Cell Line ; Dogs ; Enzyme-Linked Immunospot Assay ; Female ; Hemagglutination Inhibition Tests ; Hemagglutinins, Viral ; immunology ; Humans ; Infant ; Influenza A Virus, H9N2 Subtype ; immunology ; isolation & purification ; pathogenicity ; Interferon-gamma ; immunology ; Lung ; virology ; Lymphocytes ; immunology ; Mice ; Mice, Inbred BALB C ; Orthomyxoviridae Infections ; immunology ; virology ; Spleen ; immunology ; Trachea ; virology ; Viral Load ; Virulence

OBJECTIVETo investigate role of CD4-CD8- T cells in murine hepatitis virus type 3 (MHV-3) induced chronic viral hepatitis in C3H/Hej mice and to identify their surface markers.

METHODSThirty C3H/Hej mice received 10 Pfu MHV-3 intraperitoneally, the CD4-CD8- T cells were isolated using magnetic bead sorting on 0, 4, 15, 30, 40 days post MHV-3 infection. The cytotoxic effects of CD4-CD8- T cells on normal and infected hepatocytes, CD8+ T cells and unrelated-virus (murine cytomegalovirus, MCMV) infected CD8+ T cells were examined by non-radioactive cytotoxicity assay. The surface markers of CD4-CD8- T cells were determined by flow cytometry.

RESULTSMHV-3 infected CD4-CD8- T cells showed significant cytotoxic effect on CD8+ T cells, but not on infected hepatocytes or MCMV infected CD8+ T cells. The analysis of cell surface markers demonstrated that the CD4-CD8- T cells are a completely new T cell subset.

CONCLUSIONSCD4-CD8- T cells have significant cytotoxic effect on virus specific CD8+ T cells in MHV-3 infected C3H/Hej mice, which suggests that CD4-CD8- T cells have immune modulatory functions in the development of chronic viral hepatitis. The phenotype of these CD4-CD8- T cells detected by flow cytometry is TCR alpha beta +CD3+CD4- CD8- CD25- CD28- CD30- CD44+.

Animals ; CD4-Positive T-Lymphocytes ; immunology ; CD8-Positive T-Lymphocytes ; immunology ; Coronavirus Infections ; immunology ; pathology ; virology ; Female ; Flow Cytometry ; Hepatitis, Viral, Animal ; immunology ; pathology ; virology ; Liver ; immunology ; pathology ; Mice ; Mice, Inbred C3H ; Murine hepatitis virus ; Spleen ; immunology ; pathology ; T-Lymphocyte Subsets ; immunology ; Time Factors

OBJECTIVETo investigate the effect of human cytomegalovirus (HCMV) infection on T lymphocyte subsets in children with β-thalassemia major (TM) during the initial 6 months after allogeneic hematopoietic stem cell transplantation (Allo-HSCT).

METHODSFrom January, 2010 to January, 2011, 35 children with TM underwent Allo-HSCT. Peripheral blood samples were obtained from the children 6 month after the transplantation to examine the changes of T lymphocytes subsets in relation to HCMV seropositivity.

RESULTSThirteen children were found seropositive and 22 were seronegative for HCMV. The HCMV-seropositive children had a higher CD8⁺ cell percentage but a lower CD4⁺ cell percentage than those without HCMV infection. Compared with those seronegative for HCMV, the children with HCMV seropositivity showed increased percentages of CD8⁺ cells and CD8⁺CD28⁻ cells with a decreased percentage of CD8⁺CD28⁺ cells. A positive linear correlation was found between the percentages of CD8⁺CD28⁻ cells and CD8⁺ cells.

CONCLUSIONHCMV infection can lead to the accumulation of CD8⁺CD28 cells to cause increased CD8⁺ T cells in the peripheral blood in TM children after Allo-HSCT. The percentages of CD8⁺CD28⁻ cells has a positive linear correlation to that of CD8⁺ cells.

Adolescent ; CD8-Positive T-Lymphocytes ; immunology ; Child ; Child, Preschool ; Cytomegalovirus ; Cytomegalovirus Infections ; immunology ; Female ; Hematopoietic Stem Cell Transplantation ; Humans ; Male ; Postoperative Period ; T-Lymphocyte Subsets ; beta-Thalassemia ; immunology ; surgery ; virology