Biomedical subjects

Chang-you Wu

Publications and source records attributed to Chang-you Wu.

10 recordsLinked to original sources

PubMed2007

[Subpopulations and cytokine expression of naïve and memory T cells in normal human PBMCs].

AIM: To determine subpopulations and cytokine expression of naïve and memory T cells by polychromatic flow cytometry(PFC). METHODS: PBMCs were separated from normal human peripheral blood and stimulated by superantigen (SEB). After incubation for 5 hours, the cells were fixed, permeablized and stained with multiplecolor-labeled mAbs for cell surface and intracellular cytokines. Then they were detected by polychromatic flow cytometry and the data were analyzed by Flow Jo software. RESULTS: Based on the expression of CD45RO molecules, CD4(+) and CD8(+) T cells were classified as naïve and memory cells, which were further devided into several subsets according to the expression of CD62L and CCR7. When PBMCs were stimulated by SEB for 5 hours, CD45RO(+) and CD45RO(-) CD4(+) or CD8(+) T cells expressed IL-2, IFN-gamma and TNF-alpha. Further analysis indicated that CD62L(lo) CCR7(lo) and CCR7(+) T cells but not CD62L(hi) and CD62L(hi) CCR7(+) T cells expressed cytokines. In addition, the percentage of cytokine expression in CD62L(lo) CCR7(lo) subsets was markedly higher than that in CCR7(+) subsets. CONCLUSION: It is not scientific to identify naïve and memory cells in human T cells only based on the expression of CD45RO. Accurate determination of naïve, effector and memory cell populations can be achieved not only based on the expression of CD45RO but also according to the expression of CD62L.

CD4-Positive T-Lymphocytes↗

PubMed2006

Human memory T cell responses to SARS-CoV E protein.

E protein is a membrane component of severe acute respiratory syndrome coronavirus (SARS-CoV). Disruption of E protein may reduce viral infectivity. Thus, the SARS-CoV E protein is considered a potential target for the development of antiviral drugs. However, the cellular immune responses to E protein remain unclear in humans. In this study, we found that peripheral blood mononuclear cells (PBMCs) from fully recovered SARS individuals rapidly produced IFN-gamma and IL-2 following stimulation with a pool of 9 peptides overlapping the entire E protein sequence. Analysis of the immune responses by flow cytometry showed that both CD4+ and CD8+T cells were involved in the SARS-CoV E-specific immune responses after stimulation with SARS-CoV E peptides. Moreover, the majority of IFN-gamma+CD4+T cells were central memory cells expressing CD45RO+CCR7+CD62L-; whereas IFN-gamma+CD8+ memory T cells were mostly effector memory cells expressing CD45RO-CCR7-CD62L-. The results of T-cell responses to 9 individual peptides indicated that the E protein contained at least two major T cell epitopes (E2 amino acid [aa] 9-26 and E5-6: aa 33-57) which were important in eliciting cellular immune response to SARS-CoV E protein in humans.

Adult↗

PubMed2006

Long-lived memory T lymphocyte responses against SARS coronavirus nucleocapsid protein in SARS-recovered patients.

The nucleocapsid (N) protein is a structural component of severe acute respiratory syndrome (SARS) coronavirus (SARS-CoV) and can induce antibody responses in SARS patients during infection. However, it is not known whether SARS-CoV N protein can induce a long persistence of memory T-cell response in human. In this study, we found that peripheral blood mononuclear cells (PBMCs) from fully recovered SARS individuals rapidly produced IFN-gamma and IL-2 following stimulation with a pool of overlapping peptides that cover the entire N protein sequence. The N-specific IFN-gamma(+)CD4(+) T cells were mainly composed of CD45RA(-)CCR7(+)CD62L(-) cells, whereas IFN-gamma(+)CD8(+) memory T cells were mostly contained within CD45RA(+)CCR7(-)CD62L(-) cell population. Epitope mapping study indicated that a cluster of overlapping peptides located in the C-terminal region (amino acids [aa] 331 to 362) of N protein contained at least two different T-cell epitopes. The results indicated that human memory T-cell responses specific for SARS-CoV N protein could persist for 2 years in the absence of antigen, which would be a valuable for the design of effective vaccines against SARS-CoV and for basic studies of human T-cell memory.

CD4-Positive T-Lymphocytes↗

PubMed2006

Role of T-cell receptor V beta 8.3 peptide vaccine in the prevention of experimental autoimmune uveoretinitis.

BACKGROUND: T-cell receptor (TCR) plays an important role in the development of autoimmune diseases. Recently, it was reported that immunization of animals with TCR peptide derived from the pathogenic cells could prevent autoimmune diseases. The aim of this study was to investigate whether vaccination with a synthetic peptide from the hypervariable region of TCR V(beta) 8.3, an experimental autoimmune uveoretinitis (EAU)-associated gene, was able to prevent the disease. METHODS: EAU was induced in Lewis rats by immunization with IRBP R16 peptide emulsified in complete Freund's adjuvant (CFA). The clinical and histological appearances were scored. Delayed type hypersensitivity (DTH) and lymphocyte proliferation were detected. Cytokine levels of aqueous humour, supernatants of cells from spleen and draining lymph nodes were measured by enzyme linked immunosorbent assay (ELISA). Gene expression of TCR V(beta) 8.3 on CD(4)(+) T cells was examined by real time quantitative polymerase chain reaction (PCR). RESULTS: After vaccination, the intraocular inflammation was significantly mitigated, antigen specific DTH and lymphocyte proliferation responses were suppressed, interleukin (IL)-2 in aqueous humour, interferon (IFN)-gamma and IL-2 produced by the spleen and draining lymph node cells were significantly decreased, whereas the production of IL-4 and IL-10 were increased. The response of draining lymph node cells to TCR V(beta) 8.3 peptide was enhanced after vaccination. Inoculation with CFA alone did not affect the severity of EAU and the above parameters. The suppression of EAU was much stronger in the group of four fold inoculations than the group of two fold inoculations. The expression of TCR V(beta) 8.3 gene was significantly reduced in the group of fourfold inoculations. CONCLUSION: Vaccination with the synthetic TCR V(beta) 8.3 peptide could remarkably inhibit the development of EAU.

Animals↗

PubMed2006

Immunization with SARS-CoV S DNA vaccine generates memory CD4+ and CD8+ T cell immune responses.

An effective vaccine for severe acute respiratory syndrome (SARS) will probably require the generation and maintenance of both humoral and cellular immune responses. It has been reported that after natural infection in humans and immunization in animals with SARS-CoV vaccine, antibody is produced and persistent for a long period of time. In the present study, mice were immunized i.m. with SARS-CoV S DNA vaccine, and three different methods (ELISA, ELISPOT and FACS) were used to evaluate the immune responses when the cells were stimulated in vitro with a pool of peptides overlapping entire SARS spike protein. The results show that prime-immunization with SARS-CoV S DNA vaccine can induce both CD4(+) and CD8(+) T cell responses. Boosting with the same vaccine enhances CD4(+) and CD8(+) T cell responses in both lymphoid and nonlymphoid organs and were persistent over two months. The SARS-CoV S-specific CD4(+) and CD8(+) T cells were CD62L(-), a marker for memory cells, and -30 to 50% of the cells expressed IL-7Ralpha (CD127), a marker for the capacity of effector cells to develop into memory cells. In addition, immunization with the DNA vaccine elicited high levels of antibody production. Taken together, these data demonstrate that immunization with SARS-CoV S DNA vaccine can generate antigen-specific humoral and cellular immune responses that may contribute to long-term protection.

Animals↗

PubMed2006

Th1 memory: implications for vaccine development.

T-helper 1 (Th1) cells play a critical role, via interferon-gamma (IFN-gamma) production, in mediating intracellular killing against a variety of infectious pathogens. Thus, understanding the regulation of Th1 responses could provide better insight into vaccine design for infections requiring Th1 immunity. The cellular and molecular mechanisms that control the induction of Th1 effector cells have been well characterized. More recently, there has been substantial progress in furthering our understanding of the factors that regulate the development of Th1 memory cells. It is clear that Th1 responses are functionally heterogeneous, as defined by their ability to produce IFN-gamma. Furthermore, this heterogeneity has profound implications for the capacity of distinct lineages of Th1 cells to develop into memory cells. This review emphasizes the mechanisms controlling the differentiation of naïve CD4+ T cells into effector and then memory cells in a progressive manner. It highlights the importance of IFN-gamma as a positive regulator for inducing Th1 responses but a negative regulator for sustaining Th1 effector cells. In conclusion, we discuss how this current understanding of Th1 differentiation will inform vaccine design and better define immune correlates of protection.

Animals↗

PubMed2006

[Effect of cyclosporin A on the production of IFN-gamma by murine splenocytes].

AIM: To explore the effect of cyclosporine A (CsA) on the production of IFN-gamma by murine splenocytes after stimulation with different reagents. METHODS: Mouse splenocytes were prepared and cultured with anti-CD3 mAb alone, anti-CD3 mAb plus anti-CD28 mAb or anti-CD3 mAb plus IL-12, in the presence or absence of different concentrations of CsA. After stimulating for 3 days, the content of INF-gamma in the culture supernatant was assayed by ELISA. The effects of CsA on the expression of activated molecules on T cells and intracellular IFN-gamma production were examined at the single cell level by flow cytometry. RESULTS: The mouse splenocytes stimulated with anti-CD3 mAb, anti-CD3 mAb + anti-CD28 mAb or anti-CD3 mAb + IL-12 could produce high level of IFN-gamma, but CsA inhibited INF-gamma production in a dose-dependent manner. The inhibitory mechanism of CsA was related to the activation of splenocytes. CONCLUSION: CsA can inhibit the expressions of CD25 and CD69 on splenocytes, as well as INF-gamma production by splenocytes in a dose dependent manner.

Animals↗

PubMed2006

[Human peripheral blood CD56+ natural killer cell subsets and their phenotypic and biological properties].

OBJECTIVE: To characterize the phenotypic and biological properties of CD56(+) natural killer cells from human peripheral blood mononuclear cells (PBMCs). METHODS: Surface markers and intracellular cytotoxic molecules were stained with multi-color-labeled monoclonal antibodies and analyzed at the single cell level the relation between NK subsets and biological characteristics by flow cytometry. RESULTS: NK cells in PBMCs could be divided into two major populations, CD56(bright) and CD56(dim), based upon the expression of CD56 molecules. Both CD56(bright) and CD56(dim) expressed CD95 (Fas) with CD95(bright) and CD95(dim) subsets. CD56(dim) subsets had higher percentage of CD8, granzyme B and perforin expression compared to those of CD56(bright) subsets. In CD56(bright) and CD56(dim) subpopulations, CD95(bright) and CD8(+) subsets had higher percentage of granzyme B and perforin expression. CONCLUSION: CD56(+) NK cells in PBMCs are composed of distinct subpopulations, CD56(dim) and CD56(dim) CD8(+) NK subsets have higher percentage of granzyme B and perforin and may play an important role in the killing of target cells.

CD56 Antigen↗

PubMed2003

Prime-boost vaccination with HIV-1 Gag protein and cytosine phosphate guanosine oligodeoxynucleotide, followed by adenovirus, induces sustained and robust humoral and cellular immune responses.

A prophylactic vaccine for HIV-1 will probably require the induction and maintenance of both humoral and cellular immunity. One current strategy to achieve such long term immune responses is a prime-boost vaccination approach using a DNA priming inoculation, followed by recombinant viral boost. In this report we use a novel prime-boost approach in which the priming injections consist of recombinant HIV-1 Gag protein mixed with cytosine phosphate guanosine oligodeoxynucleotide (CpG ODN), followed by recombinant adenoviral boost expressing HIV-1 Gag. Analysis of the immune responses indicates that HIV-1 Gag protein plus CpG ODN immunization alone induces potent humoral as well as Th1 and CD8+ T cell responses. Boosting with recombinant adenovirus strikingly enhances CD8+, but not Th1, T cell responses, resulting in CD8+ T cell responses far greater in magnitude than Th1 responses. Furthermore, the Th1 and CD8+ T cell responses following prime-boost immunization were seen in both lymphoid and peripheral mucosal organs and were sustained over several months. Together, these data suggest a new immunization approach for elicitation of long term humoral and cellular immune responses.

AIDS Vaccines↗

PubMed2002

Vaccination with heat-killed leishmania antigen or recombinant leishmanial protein and CpG oligodeoxynucleotides induces long-term memory CD4+ and CD8+ T cell responses and protection against leishmania major infection.

CpG oligodeoxynucleotides (ODN) have potent effects on innate and adaptive cellular immune responses. In this report, the ability of CpG ODN to confer long-term immunity and protection when used as a vaccine adjuvant with a clinical grade of leishmanial antigen, autoclaved Leishmania major (ALM), or a recombinant leishmanial protein was studied. In two different mouse models of L. major infection, vaccination with ALM plus CpG ODN was able to control infection and markedly reduce lesion development in susceptible BALB/c and resistant C57BL/6 (B6) mice, respectively, up to 12 wk after immunization. Moreover, B6 mice immunized with ALM plus CpG ODNs were still protected against infectious challenge even 6 mo after vaccination. In terms of immune correlates of protection, ALM plus CpG ODN-vaccinated mice displayed L. major-specific T helper cell 1 and CD8+ responses. In addition, complete protection was markedly abrogated in mice depleted of CD8+ T cells at the time of vaccination. Similarly, mice vaccinated with a recombinant leishmanial protein plus CpG ODN also had long-term protection that was dependent on CD8+ T cells in vivo. Together, these data demonstrate that CpG ODN, when used as a vaccine adjuvant with either a recombinant protein or heat-killed leishmanial antigen, can induce long-term protection against an intracellular infection in a CD8-dependent manner.

Animals↗