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Helper T cells are capable of influencing a variety of immune cells, and the T cell response generated (including the extracellular signals such as cytokines) can be essential for a successful outcome from infection. In order to be effective, helper T cells must determine which cytokines will allow the immune system to be most useful or ...
CD4+ T helper cells are white blood cells that are an essential part of the human immune system. They are often referred to as CD4 cells, T helper cells or T4 cells. They are called helper cells because one of their main roles is to send signals to other types of immune cells, including CD8 killer cells, which then destroy the infectious ...
In cell-free spread (see figure), virus particles bud from an infected T cell, enter the blood or extracellular fluid and then infect another T cell following a chance encounter. [90] HIV can also disseminate by direct transmission from one cell to another by a process of cell-to-cell spread, for which two pathways have been described.
HIV is commonly transmitted via unprotected sexual activity, blood transfusions, hypodermic needles, and from mother to child.Upon acquisition of the virus, the virus replicates inside and kills T helper cells, which are required for almost all adaptive immune responses.
The CD8 + T cell response is thought to be important in controlling virus levels, which peak and then decline, as the CD4 + T cell counts recover. A good CD8 + T cell response has been linked to slower disease progression and a better prognosis, though it does not eliminate the virus. [102] Ultimately, HIV causes AIDS by depleting CD4 + T cells.
HIV tropism refers to the cell type in which the human immunodeficiency virus infects and replicates. HIV tropism of a patient's virus is measured by the Trofile assay . HIV can infect a variety of cells such as CD4+ helper T-cells and macrophages that express the CD4 molecule on their surface.
As the helper T cells grow and divide, they produce effecter helper T cells (which help coordinate the immune system response to HIV). The effector T cells utilize cytokines to mobilize other immune cells to join the combat against HIV. The cytokines promote the maturation of B cells into plasma cells. Then the plasma cells secrete antibodies ...
T cells are one of the important types of white blood cells of the immune system and play a central role in the adaptive immune response. T cells can be distinguished from other lymphocytes by the presence of a T-cell receptor (TCR) on their cell surface. T cells are born from hematopoietic stem cells, [1] found in the bone marrow.