Viral Antigens

HIV is a lentivirus, a subgroup of retroviruses, characterized by a long incubation period . It primarily infects CD4+ T cells, macrophages, and dendritic cells . The virus is composed of two strands of RNA, 15 types of viral proteins, and a lipid bilayer membrane derived from the host cell . HIV is present in bodily fluids such as blood, semen, vaginal fluids, and breast milk .

The primary function of HIV is to replicate within host cells. It targets CD4+ T cells, which play a crucial role in immune responses by coordinating the activity of other immune cells . By depleting these cells, HIV impairs the body’s ability to mount an effective immune response, leading to increased vulnerability to infections and diseases .

HIV’s life cycle involves several stages: binding, fusion, reverse transcription, integration, replication, assembly, and budding . The virus binds to CD4 receptors on the host cell surface, fuses with the cell membrane, and releases its RNA into the cell. Reverse transcriptase converts viral RNA into DNA, which is then integrated into the host genome by integrase . The host cell machinery is used to produce viral proteins and RNA, which are assembled into new virions that bud off from the cell, ready to infect other cells .

HIV gene expression and latency are regulated by various mechanisms, including transcriptional regulation and post-transcriptional modifications . Long noncoding RNAs (lncRNAs) play a significant role in modulating HIV gene expression, acting as either activators or inhibitors . Epigenetic modifications, such as DNA methylation and histone modification, also influence viral transcription and latency .

HIV research has led to significant advancements in biomedical research, including the development of antiretroviral therapies (ART) that suppress viral replication and improve the quality of life for people living with HIV . HIV is also used as a model to study viral pathogenesis, immune responses, and the development of vaccines . Diagnostic tools, such as HIV antibody tests and nucleic acid tests, are crucial for early detection and management of the infection .

HIV plays a critical role throughout its life cycle, from initial infection to the development of AIDS. The virus hijacks the host cell machinery to replicate and spread, leading to the gradual depletion of CD4+ T cells . Without treatment, HIV progresses through several stages: acute infection, chronic infection, and AIDS . Antiretroviral therapy can significantly slow this progression, allowing individuals to live longer, healthier lives .