Immunologic aspects of HIV infection.

J A Caetano

Abstract


Infection of Human organism by Human Immunodeficiency viruses induces, after a shorter or a longer period, a complex immune Deficiency (ID) that has been named Acquired Immune Deficiency Syndrome (AIDS). Although the designation is not correct, it has been accepted by the scientific community. AIDS includes multiple clinical situations that have in common HIV infection and an almost constant ID, that at the end of natural course of infection manifestated by the presence of opportunistic infections and malignant tumors. HIV-1 and HIV-2 are slow RNA viruses with a common architecture and well known genomic organization. The characteristics that made HIV infectious agent n. 1 in XXth Century are their remarkable heterogeneity, close AA sequence homology between some of their proteins and relevant molecules in human beings: MHC molecules, IL-2, VIP, etc. and a strong affinity of gp 120 to CD4 receptor of T helper lymphocytes (T4), mononuclear phagocytes, natural killer cells, etc. all of them sharing a relevant role in normal immune response (IR). Affected in its cornerstones of cellular defense, human organism starts an immune defense through antibodies, cytotoxic T Lymphocytes (CTL) Natural Killer Cells (NK) antibody dependent cell cytotoxicity (ADCC), that fails. Activating immune system HIV turn that defense strategy to their own profit and enhanced replication. After an apparent latency period--in which the balance seems to favor the host--new viral variants arise due to high rate of HIV mutagenesis, that in turn stimulate immune system, induce new cycles of viral replication and new high virulent mutants, leading to the final collapse of Immune System.(ABSTRACT TRUNCATED AT 250 WORDS)

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