HIV/AIDS Flashcards
what does HIV stand for?
human immunodeficiency virus
what does AIDS stand for?
acquired immune deficiency syndrome
what type of virus is HIV and why?
it is a retrovirus because it has the ability to transcribe RNA into DNA
features of structure of HIV
- lipid envelope
- surface proteins - used to attach HIV onto receptors of T cells and macrophages
- capsid (protein layer encloses nucleic acid)
- RNA - two identical strands which contain genetic blueprint to make more viruses
- reverse transcriptase - enzyme catalyses production of DNA when inside host cell
what are the first two stages of the infection of helper T cell with HIV?
- attracted to CD4 receptors on surface of cell
- uses specific binding with attachment proteins
- particle fuses with membrane and capsid removed by enzymes (ENDOCYTOSIS)
how is DNA formed and where is it placed?
- reverse transcriptase forms DNA using RNA as template
- complimentary strand is formed
- inserted into host cell’s chromosome
how are HIV proteins formed?
- viral genes transcribed into mRNA
- mRNA transcribed into proteins (protein synthesis)
what happens after proteins are formed?
- capsids assemble around viral genomes
- new viruses are budded off host cell
what symptoms can occur as a result of HIV infection?
- medical examination: swollen lymph glands
- opportunist infections
why do opportunist infections occur?
due to immunosuppressed system and depleted population of helper T cells
other symptoms of AIDS
- eye infection
- karposi’s sarcoma (malignant skin tumour)
- oral thrush
- weight loss
- diarrhea
- fever
- lymphoma of brain
- dementia
- autoimmune diseases (thrombocytopenia - reduced platelet count)
- skin inflammation (dermatitis)
What type of test is the ELISA test?
blood test
what does ELISA stand for?
enzyme-linked immunosorbent assay
how does ELISA test work?
- well coated with HIV antigen
- add serum (contains blood plasma)
- if antibodies are present then, will attach to antigen
- wells are washed to get rid of excess
- second antibody is covalently conjugated to enzyme linking to first antibody
- wash well again to remove excess
- add colorgenic solution of enzyme-substrate
- should turn pink if antibody present
how can the severity of the infection be checked from ELISA test?
use a colorimeter to check intensity of colour - stronger the colour more severe infection
