Microbiology / Infectious Disease
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12503/31259
Browse
Browsing Microbiology / Infectious Disease by Subject "HIV"
Now showing 1 - 2 of 2
- Results Per Page
- Sort Options
Item HIV AND HCV INFECTION OF THE BRAIN IN HUMANIZED MICE(2013-04-12) Zhang, ZiugenPurpose: In this study, we wished to determine the possibility of HIV and HCV infections in the brains of these mice in preparation of using the mice to study HIV and HCV co-infection of the brain and the roles of the co-infection in HIV/HCV-associated neurological diseases . Methods: Human CD34+ human hematopoietic stem cells (HSC) and hepatocyte progenitors were co-transplanted into the Balb/CRag2-/-𝛄C-null mice, which led to efficient engraftment of human leukocytes and hepatocytes. These humanized mice were infected with HCV alone or HCV and HIV. Two months after infection, livers and brains of these mice were collected. Half of the brain was fixed and paraffin-embedded for immunostaining for HIV p24 and HCV core; the other half of the brain was used for DNA and RNA extraction. Polymerase Chain Reaction (PCR) was performed to detect HIV DNA; Strand-specific Reverse Transcription Polymerase Chain Reaction (RT-PCR) was performed to detect positive-strand and negative strand HCV RNA. Results: Three of four mice in HCV mono-infected group, one of five mouse in the HCV/HIV co-infected group showed severe fibrosis in liver. The HCV core protein and HIV P24 protein were detected in the brain, although faint. All 5 mouse infected with HIV were detected for HIV DNA in the brain. All 4 HCV mono-infected mice and all 5 HCV/HIV co-infected mice were detected for positive-strand HCV RNA in their brains, while only 3 of those brains were detected for negative-strand HCV RNA. Conclusions: These results showed that HCV and HIV are both capable of gaining access into the brain and replicating in the brain of these mice and suggest that humanized mice could be used to study the effects of HCV infection and HCV/HIV co-infection on the brain dysfunction.Item INTERCELLULAR TRANSFER OF HIV-1 NEF AMONG CD4 T CELLS IS MEDIATED BY DIRECT CELL-CELL CONTACT(2013-04-12) Luo, XiaoyuPurpose: HIV-1 Nef is an essential pathogenic factor for acquired immunodeficiency syndrome disease progression. It binds to over 30 putative cellular components and initiates a great variety of functions. Recent studies have demonstrated that Nef can be transferred from infected cells to uninfected cells and leads to significant changes on the bystander cells. This intercellular Nef transfer is possibly linked to the massive depletion of CD4 T cells in disease progression. However, the underlying mechanism for the intercellular Nef transfer is still not fully understood. In this study, by using advanced tools, we tested two potential mechanisms for intercellular Nef transfer among CD4 T cells including direct Nef transfer through cell-cell contact and Nef secretion in the form of exosomes. Methods: Nef-GFP Jurkat cells were co-cultured with red dye-labeled uninfected Jurkat cells for 8 hours. Cell mixture was analyzed under florescence microscope. To determine the percentage of Nef transfer during HIV infection, HIV and HIV Nef-deleted virus-infected jurkat cells were collected when cells reached 50% infected. The percentage of Nef+ cells in uninfected population and how it affected by cell density was analyzed by Immunostaining and flow-cytometry. In order to test if exosomes are involved in intercellular Nef transfer among CD4 T cells, we utilized optiprep gradient centrifugation to separate exosomes from viral particles and then detect Nef expression in exosome fractions. Results: Nef was detected in the bystander Jurkat cells after co-cultured with Nef-expressing /infected Jurkat cells. Nef was transferred through nanotubes and filopodia bridges by forming connections between infected cells and uninfected cells. There was about 3-10% of uninfected cells that were found to be Nef+ in infected Jurkat cells (50% infection). The intercellular Nef transfer was enhanced by increasing the cell density. Using optiprep gradient centrifugation, virus was successfully separated with exosomes and Nef was only detected in the virus fractions but not exosome fractions. Conclusions: Taken together, our studies showed that Nef can be transferred to uninfected bystander CD4+ T cells either from Nef-expressing cells or from HIV-infected cells. This intercellular Nef transfer is mediated by direct cell-cell contact possibly through synapse or nanotube like structures. Exosome is not involved in the intercellular Nef transfer.