贵州登革病毒疫源地调查及毒力相关性的研究

The BALB/c mice model were successful foundated with dengue virus type 2 NGC and B strain(isolated from the dengue hemorrhagic fever patient serum) infection. The mice were infected with dengue virus type 2 by multisubcutaneruly injection at various doses of two DV2 strains (NGC and B strain ). The injected mice presented typical clinical manifestations including the fever, decreased platelet counts as well as viremia. The production of specific antibodies of the infected BALB/c mice after primary and secondary injection showed some difference. However, BALB/c mice infected by the B strain showed the prolonged viremia. The dynamic curve of specific antibody and the viremia induced by various DV2 strains were different in some existence. The viral RNA were detected in the murine liver, kidney, spleen, and brain. It existed longest in brain, shortest in liver. The cytokines of the infected mice, such as IL-2、IL-4、IL-5、IL-6、IL-10、IFN-γ, were different. BALB/c mice infected with DV2 B strain could produce higher IL-4 and IFN-γthan infected with DV2 NGC strain. The concentrations of the CKs production had closely relationship with the doses of the virus. The lever of IL-4 and IFN-γboth increased after the first infection, but IL-4 increased more predominantly than IFN-γin the secondary infected phase. It suggested that IL-4 and IFN-γplay important roles in the diseases coursed by DV. Furthermore, Th1 and Th2 responses were both arose by DV in the first infection phase.While in the second infection phase, Th1 responses was more predominant than Th2 responses. But for NGC strain, infection eliciting a dominant humoral immune response induced expression of Th2-related CKs at the early phase, whereas those showed some appearance of Th1 Cks at the later phase. It showed that Th1 response played a role to inhibite Th2 response. And Th cell and the CKs were critic to the DV infective diseases. A new strain was isolated from Aedes albopictus collected from Mawei area in Guizhou province. And it was identified dengue virus type 2. We also detected the viral nucleic acid in the Aedes albopictus. The E gene and NS1 gene of DV2 NGC and B strains were amplified by RT-PCR. The PCR production were sequenced. The E gene and NS1 gene sequences of B strain have been submitted to GenBank, the accession number are AY179733 and AY219180. These results showed that the virulence of DV2 is correlated with the mutation of virus gene.

调查贵州自然界白纹伊蚊登革病毒带毒情况及研究其对登革病毒（Dengue virus,DV）的易感性，对300例夏秋季发热病人血清作DV特异性IgM、IgG抗体检测，病毒分离、核酸检测，从机体细胞分子水平完成贵州省DV自然疫源地及登革热的流行病学调查。利用不同毒株建立小鼠模型，研究免疫应答机制。通过对E、NS1基因序列测定，探讨碱基序列改变与毒力的相关性。.