Immunohistochemical study of amelogenin binding proteins in an amelogenin point mutation mouse / Estudio inmunohistoquímico de proteínas de unión de la amelogenina en un ratón con mutación puntual de amelogenina

Amelogenin is one of the enamel matrices secreted by ameloblasts. A mutation of the amelogenin gene can cause hereditary dental enamel defects known as amelogenesis imperfecta (AI). Since lysosome-associated membrane protein-1 (LAMP-1), -3 (LAMP-3), and 78kDa glucose-related protein (Grp78) were identified as binding proteins of amelogenin, several studies have suggested the involvement of these binding proteins with the cell kinetics of ameloblasts in normal or abnormal conditions. The purpose of this study is to investigate the distribution of these amelogenin binding proteins in the ameloblast cell differentiation of mice with a point mutation of the amelogenin gene (Amelx*). The incisors of Amelx* mice had a white opaque color and the tooth surface was observed to be rough under a scanning electron microscope. Among the sequential ameloblast cell differentiation in the Amelx* mice, the shape of ameloblasts at the transition stage was irregular in comparison to those in wild-type (WT) mice. Immunostaining of Grp78 revealed that the whole cytoplasm of the transition stage ameloblasts was immunopositive for Grp78 antibody, while only the distal part of cell was positive in the WT mice. Furthermore, in the Amelx* mice, the cytoplasm of the transition stage ameloblasts was immunopositive for LAMP-1 and LAMP-3. These results suggest that Amelx* may cause the abnormal distribution of amelogenin binding proteins in the cytoplasm of ameloblasts.

La amelogenina es una de las matrices de esmalte secretadas por los ameloblastos. Una mutación del gen de amelogenina puede causar defectos hereditarios del esmalte dental conocidos como amelogénesis imperfecta (AI). Dado que la proteína de membrana asociada a lisosoma-1 (LAMP-1), -3 (LAMP-3) y la proteína relacionada con la glucosa de 78 kDa (Grp78) se identificaron como proteína de unión a amelogenina, varios estudios han sugerido la participación de estas proteínas con la cinética celular de los ameloblastos en condiciones normales o anormales. El objetivo del estudio fue investigar la distribución de LAMP-1, LAM-3 y Grp78 durante la diferenciación celular de ameloblastos de ratones con una mutación puntual del gen de amelogenina (Amelx*). Los incisivos de los ratones Amelx* presentaron un color blanco opaco y se observó en microscopio electrónico de barrido que la superficie del diente era áspera. La diferenciación celular secuencial y la forma de los ameloblastos en la etapa de transición en los ratones Amelx* fue irregular en comparación con los ratones silvestres (RS). La inmunotinción de Grp78 reveló que todo el citoplasma de los ameloblastos en etapa de transición fue inmunopositivo para el anticuerpo Grp78, mientras que solo la parte distal de la célula fue positiva en los ratones RS. Además, en ratones Amelx*, el citoplasma de los ameloblastos en etapa de transición fue inmunopositivo para LAMP-1 y LAMP-3. Estos resultados sugieren que Amelx* puede causar distribución anormal de proteínas de unión a amelogenina en el citoplasma de los ameloblastos.

CD107a expression and IFN-gamma production as markers for evaluation of cytotoxic CD3+ CD8+ T cell response to CMV antigen in women with recurrent spontaneous abortion

Some evidence has shown a relationship between primary human cytomegalovirus [CMV] infection and pregnancy loss. The impact of CMV infection reactivation during pregnancy on adverse pregnancy outcomes is not completely understood. It is proposed that altered immune response, and therefore, recurrence or reactivation of latent CMV infection may relate to recurrent spontaneous abortion [RSA]; however, few data are available in this regard. To find out about any cell mediated defect and reactivation of latent CMV infection in women with RPL, cellular immunity to the virus has been evaluated by specific cytotoxic T lymphocyte [CTL] response to CMV. In a case control study, CTL CD107a expression and intercellular IFN-gamma production in response to CMV pp65 antigen and staphylococcus enterotoxin B [SEB] in women with RSA were assessed by flow cytometric analysis. Forty-four cases with history of recurrent pregnancy and forty-four controls with history of successful pregnancies were included. The FACSCaliber flow cytometer were used for analysis. No significant difference was observed between CD107a expression and IFN-gamma production in response to CMV PP65 antigen in RPL patients and control group. However, the cytotoxic response to SEB antigen in patients with RPL was significantly lower than control group [p=0.042]. The results of this study show that impaired CD107a expression and IFN-gamma production as CTL response to CMV does not appear to be a major contributing and immune incompetence factor in patients with RPL, but cytotoxic T cell response defect to other antigens requires to be assessed further in these patients

Screening for cytotoxic defects with flow cytometric detection of CD107α on natural killer cells and cytotoxic lymphocyte cells / 中华儿科杂志

<p><b>OBJECTIVE</b>To establish a novel flow cytometry-based assay for measuring the expression of lysosomal-associated membrane protein 1 (LAMP-1, CD107α) on the cell surface of natural killer (NK) cells and cytotoxic T lymphocyte (CTL) and evaluate the screening value of this assay for cytotoxic defects-related diseases such as familial hemophagocytic lymphopro-liferative (FHL) syndrome.</p><p><b>METHOD</b>Three suspected Chediak-Higashi Syndrome (CHS) patients, three suspected FHL patients and 10 healthy children were enrolled in the study from October 2010 to June 2011. Their PBMCs were separated and activated overnight with IL-2. After the granule release of NK cells activated by phytohemagglutinin (PHA) and CD8+T cells by anti-CD3, the CD107α expression were analyzed by flow cytometry. The peripheral blood DNA and RNA of the patients were extracted to analyze the pathogenic genes via DNA-PCR/RT-PCR and direct sequencing.</p><p><b>RESULT</b>The CD107α expression on CTL in the ten healthy children significantly increased after activation by anti-CD3 [(0.18 ± 0.07)% vs. (4.47 ± 2.36)%, P < 0.05] and NK cells after activation by PHA [(0.27 ± 0.07)% vs. (5.80 ± 2.83)%, P < 0.05]. The frequency of CD107α-expression NK cells in three suspected CHS after activation was significantly elevated when compared with the healthy control [0.5%, 0.6% vs. (5.80 ± 2.83)%] except patient 2. After the anti-CD3 activation, the frequency of CD107α expression on CTL cells also showed no significant difference [0.3%, 0.9%, 0.2% vs. (4.47 ± 2.36)%] in three patients. All of their mean fluorescence intensity (MFI) showed the same trend. Patient 1 and 3 were identified to have LYST mutations (Patient 1: c.5411-5414 del TTTC, L1741fsX1758 and c.7975 C > T, R2596X; Patient 3: c.4863G > A, R1563H and c.5392-5393delAA, E1739fsX1756). There was no mutation identified in the LYST gene for patient 2. CD107α expression of NK cells and CTL in the suspected FHL patients and in mirror of these findings, no underlying gene variation of PRF, MUNC13-4 and STX11 were identified.</p><p><b>CONCLUSION</b>We developed a method to quantitatively assess cytotoxicity of the NK cells and CTL by measuring the expression of CD107α on the cell membrane, which appeared to be an effective and rapid screening test for cytotoxic defects-related diseases such as FHL and other HLH secondary to primary immunodeficiency.</p>

The cytotoxic effect of CD8+ T subsets plays an important role in the chronic hepatitis B / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>The aim of this study is to explore the cytotoxic effect of CD8+ T subsets in peripheral blood with chronic hepatitis B subjects who are at immune tolerance phase and immune clearance phase (before and after three months' treatment with interferon-alpha), further to investigate their impact in the pathogenesis of chronic hepatitis B and antiviral therapy.</p><p><b>METHODS</b>The subjects of chronic hepatitis B, including 20 subjects of immune tolerance phase and 20 subjects of immune clearance phase, are enrolled in the study. And we use flow cytometry to detect Lysosome-associated membrane protein-1 (LAMP-1, CD107a) and Granzyme B (GrB) expression of CD8(high) and CD8(low) T cells in peripheral blood with chronic hepatitis B subjects.</p><p><b>RESULTS</b>(1) At immune clearance phase, the CD8+ T subsets expressing GrB and CD107a are higher than counterpart of immune tolerance phase. (2) At immune tolerance phase and immune clearance phase in HBV infection, the CD8(low) T cells expressing GrB and CD107a are higher than that of CD8(high) T cells. (3) After three months' treatment with interferon-a, except for GrB+ CD107a+ CD8(high) T cells, CD8(high) T cells expressing GrB and CD107a present a tendency of ascensus at the same time with that of CD8(low) T cells a tendency of descensus except for GrB(-)CD107a+ CD8(low) T cells. (4) The CD8+ T cell expressing GrB and CD107a, correlate positively with HBV DNA load at immune tolerance phase, but correlated negatively at immune clearance phase.</p><p><b>CONCLUSIONS</b>(1) GrB and CD107a molecule expressed by different CD8+ T cell subsets play an important role in disease evolution and antivirus therapy of chronic hepatitis B, the cytotoxic effect of CD8(high) T cell subset became more and more stronger during the treatment of IFN-alpha, and the cytotoxic effect of CD8(low) T cell subset couldn't be neglected before antivirus therapy. (2) To some degree, the correlation between HBV-DNA load and the expression of GrB and CD107a at different CD8+ T cell subsets, could hint the relationship between virus and immune response.</p>

Construction of hu-PBL/SCID chimeras and development of EBV-related lymphomas / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To construct hu-PBL/SCID chimeras and to investigate the development of lymphoma and oncogenicity of the Epstein-Barr virus (EBV).</p><p><b>METHODS</b>Human peripheral blood lymphocytes (PBLs) were isolated from healthy adult donors and transplanted intraperitoneally into severe combined immunodeficient (SCID) mice. Mice with hu-PBL engraftment from healthy EBV seronegative donors were injected intraperitoneally with EBV-containing supernatant from suspension culture of B95-8 cell line (active infection), whereas mice receiving lymphocytes from healthy EBV seropositive donors were not re-infected with B95-8 derived EBV (latent infection). Pathological examination and molecular analysis were performed on experimental animals and induced neoplasms.</p><p><b>RESULTS</b>In the early stage of this experiment, 12 mice died of acute graft-versus-host disease, mortality was 34.3% (12/35 mice) with an average life span of 17.5 days. In 19 survival hu-PBL/SCID chimeric recipients from 12 healthy donors, tumor incidence was 84.2% (16/19 mice). The average survival time of tumor-bearing mice was 65.5 days. EBV-related neoplasms in SCID mice were nodular tumors with aggressive and fatal features. Histological morphology of tumors exhibited diffuse large cell lymphomas. Immunohistochemistry revealed that LCA (CD45) and L26 (CD20) were positive, but both PS1 (CD3) and UCHL-1 (CD45RO) were negative, and EBV products ZEBRA, LMP1, and EBNA2 were expressed in a small number of tumor cells. EB virus particles were seen in the nuclei of some tumor cells by electron microscopy, and EBV DNA could be amplified in the tumor tissues by PCR. In situ hybridization indicated that the nuclei of tumor cells contained human-specific Alu sequence.</p><p><b>CONCLUSIONS</b>EBV-induced tumors were human B-cell malignant lymphomas. We obtained direct causative evidence dealing with EBV-associated tumor deriving from normal human cells.</p>