Biomedical subjects

Li-tao Yang

Publications and source records attributed to Li-tao Yang.

3 recordsLinked to original sources

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↗

PubMed2005

[The value of metastatic lymph nodes ratio in predicting the prognosis of patients with T3 gastric carcinoma].

OBJECTIVE: To evaluate the value of the metastatic lymph node ratio (MLR) in predicting the postoperatively survival time of patients with T(3) gastric carcinoma. METHODS: Eighty-nine patients with T(3) gastric carcinoma who underwent curative gastrectomy were analyzed retrospectively. The correlations between MLR, positive nodes and the total lymph nodes (15 or more) in histologic examination were analyzed using Spearman's correlation analysis. The influence of MLR and positive nodes on survival time of patients was identified with univariate Kaplan-Meier survival analysis and multivariate Cox proportional hazard model analysis. The predicting accuracy of MLR to death of patients within 2 years postoperatively was determined by receiver working characteristic curve and was compared with that of positive nodes. RESULTS: (1) The MLR did not correlate with the total lymph nodes in histologic examination (Spearman's correlation coefficient was -0.0022, P > 0.05), whereas positive lymph nodes did (correlation coefficient was 0.2504, P < 0.05). (2) Kaplan-Meier survival analysis identified that the MLR influenced significantly the survival time postoperatively (Log-rank chi(2) = 35.7470, P < 0.01). Cox proportional hazard model showed the high MLR was an independent poor prognostic factor (chi(2) = 7.9708, P < 0.01). (3) There was not difference between the area under the receiver working curve of MLR and positive nodes to predict the death of patients within 2 years postoperatively (P > 0.05). CONCLUSION: The MLR in T(3) gastric carcinoma is not correlated with the number of total lymph nodes examined on the condition that 15 or more lymph nodes were assessed in pathology. The predicting accuracy of MLR to death of patients with T(3) gastric carcinoma within 2 years postoperatively is same as, but not better than that of positive nodes if the extent of lymphadenectomy is optimal.

Adult↗