Hiv Interactions With Dendritic Cells

Given rapid research progress and advance of the techniques in studying HIV interactions with host cells and factors, there is a critical need for a book on HIV interactions with DCs. The proposed book will aim for a broad readership to facilitate HIV/AIDS research and provide a practical tool for HIV researchers to continuously address novel questions. Specifically, the editors will summarize the literature in this field and provide critical analysis and future directions. International researchers will be invited as contributors of the book, highlighting authors who have contributed significantly to the field from different angles and aspects of virology, cell biology and immunology, etc.

Dendritic cells are key players during HIV pathogenesis, and shape both the immediate immune response at the site of infection as well as directing the adaptive immune response against the virus. HIV has developed a plethora of immune evasion mechanisms that hijack dendritic cell functions, suppressing their ability to mount an accurate immune response and exploiting them for efficient viral transfer to target T cells. To achieve successful replication within dendritic cells without triggering danger signaling, HIV accomplishes a delicate balance where only a low level of transcription can be sustained without triggering antiviral responses that would harm the virus. Here, we describe how the presence of HSV2 coinfection, which is very common in geographic areas with a high HIV prevalence and almost triples the risk of HIV acquisition, alters dendritic cell state to support much higher levels of HIV infection. We found this effect to be mediated by the STING pathway, which is involved in the sensing of DNA in the cell cytosol. STING activation led to an upregulation of factors such as IRF3 and NFkB that can be used for HIV transcription and a degradation of factors that restrict HIV replication. In addition, we describe how HIV exploits the human complement system, a group of proteins that usually help the human body to identify dangerous pathogens while avoiding reaction towards self. HIV can coat itself, i.e. become opsonized, in complement fragments that are typically only present on the body’s own cells, allowing it to activate signaling pathways that are associated with tolerance. Dendritic cells that come into contact with complement opsonized HIV do not mount danger responses, despite the fact that HIV-derived single stranded RNA triggers the pathogen recognition receptor TLR8. The suppression of danger responses is mediated by activation of complement receptor 3, and leads to an increased infection of the dendritic cell and affects its interactions with other immune cells. There is a lack of recruitment of NK cells to the site of infection, and an inhibition of NK cell killing, which plays an important role in the destruction of HIV-infected cells in vivo. T cells primed by dendritic cells exposed to complement opsonized HIV have a lower ability to develop towards effector phenotype, and have an increased expression of the markers PD1, TIM3 and LAG3 which are associated with T cell dysfunction and exhaustion. In addition, T cells primed by these dendritic cells in the presence of NK cells upregulate markers CD38, CXCR3 and CCR4, which have been linked to an increased susceptibility to HIV infection. In summary, we add to the current knowledge on HIV immune evasion mechanisms that allow the virus to establish infection, as well as describing mechanisms that govern whether dendritic cells mount danger signaling and an immune response or not.

Dendritic cells are vital to induce potent anti-viral immune responses. It will become clear to the reader that dendritic cells often play a dual role during viral infections. On the one hand they are able to mount potent antiviral immune responses, and on the other hand several viruses, including HIV-1, use DC as a vector to be transferred from the periphery to the lymph nodes where they infect their prime target.

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This book gives a comprehensive overview of HIV and AIDS including NeuroAIDS, as well as general concepts of pathology, immunity and immunopathology, diagnosis, treatment, epidemiology and etiology to current clinical recommendations in management of HIV/AIDS including NeuroAIDS, highlighting the ongoing issues, recent advances and future directions in diagnostic approaches and therapeutic strategies.

Great advances have taken place in basic research and the clinical usefulness of dendritic cells (DCs). It has now been clearly established, for instance, that these cells play a crucial role in immune responses against infectious diseases and cancers. Antigen-presenting DCs are widely distributed in the body and regulate both immunity and immune tolerance. Experimental studies have provided important insights into DCs and how they can be used for treating animal models of various diseases that occur in humans. The role of these cells in pathogenesis and the treatment of human diseases is elaborately set forth in this valuable book. Researchers in the field are optimistic that DCs, already in use for treating patients with cancers, soon can be used therapeutically for patients with chronic infections, autoimmune diseases, and allergic manifestations. This volume provides a working definition of DCs and also explains the phenotypes and functions of DCs so that these can be readily understood not only by clinicians but by immunologists, researchers, and students as well.

HIV remains the major global health threat, and neither vaccine nor cure is available. Increasing our knowledge on HIV infection will help overcome the challenge of HIV/AIDS. This book covers several aspects of HIV-host interactions in vitro and in vivo. The first section covers the interaction between cellular components and HIV proteins, Integrase, Tat, and Nef. It also discusses the clinical relevance of HIV superinfection. The next two chapters focus on the role of innate immunity including dendritic cells and defensins in HIV infection followed by the section on the impact of host factors on HIV pathogenesis. The section of co-infection includes the impact of Human herpesvirus 6 and Trichomonas vaginalis on HIV infection. The final section focuses on generation of HIV molecular clones that can be used in macaques and the potential use of cotton rats for HIV studies.