Thesis (Ph. D.)--University of Hawaii at Manoa, 2005. / Includes bibliographical references (leaves 158-166).

Macrophages are a natural target cell for HIV-1 infection, and they contribute to the development of disease as they are important for transmission, dissemination and persistence of the virus in an infected patient. Macrophages are less well-studied than T cells and cell lines in relation to HIV-1 infection, yet macrophages are highly specialised and key aspects of the HIV-1 life cycle in these cells are already known to differ compared to other cell types. HIV-1 entry into macrophages has been suggested to occur by macropinocytosis, however the entry route in these cells has not been fully characterised. In this thesis I have tested a panel of pharmacological inhibitors of cellular proteins and uptake pathways, in order to delineate the requirements for HIV-1 entry into macrophages and to determine the nature of the entry route. My findings suggest that the following host factors are important for entry; membrane cholesterol, actin rearrangements, dynamin, sodium-hydrogen exchange, Pak1, and Rac. Other factors including clathrin, PI-3 kinase, Rho kinase and some isoforms of PKC were found to be dispensable for infection or to inhibit infection. Macrophages are a heterogeneous group of cells, and tissue macrophages from different parts of the body differ in their morphology, phenotype and function. I have used the growth factors M-CSF and GM-CSF to direct monocytes to differentiate into distinct types of macrophage. This allowed me to determine that different macrophages differ in their susceptibility to infection and in their ability to support replication. This is likely to be due to variation in HIV-1 receptor expression and the levels of key HIV-1 transcription factors, respectively. Overall this thesis contributes to existing knowledge regarding HIV-1 infection of macrophages. These findings may assist with the design of entry inhibitors, and with therapies designed to eradicate HIV-1 from infected individuals.