Related Experiment Video
Updated: Apr 28, 2026
An In vitro Co-infection Model to Study Plasmodium falciparum-HIV-1 Interactions in Human Primary Monocyte-derived Immune Cells
Published on: August 15, 2012
Antigen-presenting phagocytic cells ingest malaria parasites and increase HIV replication in a tumor necrosis factor
Marika Orlov1, Florin Vaida2, Kathryn Williamson3
1University of California-San Diego, La Jolla Seattle Biomedical Research Institute, Washington.
Background:
Plasmodium falciparum infection induces human immunodeficiency virus (HIV) replication and accelerates a decline in CD4(+) T-cell count. The mechanisms contributing to these interactions have not been fully elucidated.
Methods:
We infected peripheral blood mononuclear cells (PBMCs) with HIV type 1 (HIV-1) and then cocultured them with P. falciparum-infected red blood cells (iRBCs) or uninfected RBCs (uRBCs). Levels of HIV-1 p24 antigen and activation-associated cytokines were measured in culture supernatants. T-cell surface activation was assessed by flow cytometry.
Results:
It has been reported that iRBCs increase HIV replication, compared with uRBCs; that neutralizing tumor necrosis factor α (TNF-α) abrogates this increase; and that hemozoin enhances HIV production. In this study, we confirmed that TNF-α plays an important role in this interaction. We show that iRBCs increased CD4(+) T-cell expression of HLA-DR(+)/CD38(+) (P = .001), that monocyte/macrophage depletion reduced HIV production by 40%-50% (P < .001), and that hemozoin-laden monocytes/macrophages that were preincubated with iRBCs also stimulated HIV production.
Conclusions:
iRBCs activate CD4(+) T cells and stimulate HIV replication in a TNF-α-dependent manner following malarial antigen processing by monocytes/macrophages. These results suggest that the persistent elevation of HIV replication during and after acute bouts of P. falciparum malaria may be due, at least in part, to ongoing stimulation of CD4(+) T cells by hemozoin-loaded antigen-presenting cells within lymphoid tissues.
More Related Videos
07:32Phagosome Migration and Velocity Measured in Live Primary Human Macrophages Infected with HIV-1
Published on: September 5, 2016
09:57Measuring Naturally Acquired Phagocytosis-Inducing Antibodies to Plasmodium falciparum Parasites by a Flow Cytometry-Based Assay
Published on: August 6, 2020
Related Concept Videos
01:29Immune Response Against Viral Pathogens
NK Cells
NK cells are a crucial part of our innate immune system, acting as the first line of defense against viral infections. These cells can recognize and kill infected cells without prior exposure to the virus, effectively slowing down the spread of infection. Additionally, NK cells produce proinflammatory...
01:22Antigen Presenting Cells
T cells require the help of antigen-presenting cells (APCs), which process foreign antigens into smaller fragments that can be recognized by T cells. These APCs are highly specialized cells that efficiently internalize antigens...
01:40Cell-mediated Immune Responses
01:27Cytotoxic T Cells-mediated Immune Response
Immunological surveillance is the ability of immune cells to monitor and eliminate infected cells with intracellular pathogens, neoplastically transformed cells, and cells with non-self antigens. Cytotoxic T cells and NK...
01:28Cells of the Innate Immune Response
Phagocytes
Phagocytes police the peripheral tissues by removing cellular debris and responding to the invasion of foreign substances or pathogens. Many phagocytes attack and remove microorganisms even before lymphocytes detect them. The human body has two general...
01:31Defense Against Bacterial Pathogens
Phagocytes
Phagocytes are the frontline soldiers of the immune system. They include neutrophils and macrophages. Neutrophils are the most abundant type of white blood cell and are quickly mobilized to the site of infection. Macrophages are larger cells that patrol...