Immunology Flashcards
Describe phagocytosis
•Engulf pathogen by endocytosis
•Forming vesicle/phagosome which fuses with lysosome
•Lysosomes contains hydrolytic enzymes (lysozymes) that hydrolyse molecules of pathogen OR digests pathogen
•Antigens are displayed on cell membrane
•Waste material is also removed by exocytosis
Describe how vaccination leads to production of antibodies and immunological memory
•Vaccine contains antigen from pathogen
•Phagocyte engulfs and presents antigen on its surface
•T helper lymphocyte with complementary receptor protein binds to antigen
•T helper lymphocyte releases cytokines to stimulate specific B lymphocyte to divide by mitosis ( clonal expansion)
•Clones become plasma cells which produce and secret (monoclonal) antibodies complementary with antigen
•Clones become memory B lymphocytes which remain in blood and recognise antigen for a more rapid response and release of more antibodies upon second infection
Describe the structure of HIV
•Genetic material is RNA
•Container in a capsid
•Contains reverse transcriptase
•Phospholipid envelope
•Has attachment proteins on lipid envelope
Describe the HIV replicates
•Attachment proteins complementary and bind to proteins on T helper cell
•Capsid broken down and releases viral RNA
•Reverse transcriptase converts viral RNA to cDNA
•Viral cDNA incorporated into host DNA ( now infected)
•Transcription of viral DNA into mRNA
•Translation of HIV proteins and formation of virions (infectious particle)
•Virions bud off the host cell membrane forming their lipid bilayer
