Immunology Flashcards
What are the primary lymphoid tissues and what are their roles?
Thymus and red bone marrow
Sites where lymphocytes form and mature
What are the secondary lymphoid tissues and what are their roles?
Spleen, tonsils, appendix, adenoids, lymph noes, peyers patches (small intestine)
Monitor EC fluids
What is lymph?
A plasma like fluid, but with less suspended proteins
What is the difference between acquired and innate immunity?
Innate immunity is a non-specific first line of defence, while acquired immunity is specific
Which innate immunity cells are the first line of defence?
Phagocytes (macrophages, eosinophils, neutrophils, monocytes)
Which lymphocyte performs immunological surveillance and what do they do?
Natural Killer Cells - screen normal tissue for abnormalities - release perforins into target cell which cause pores and leads to lysis
What are interferons?
Chemical messengers which indicate viral infection and bind to neighbouring cells to activate immune cells.
What is the classical pathway of the complement system?
C1 enzyme interacts with an antigen-antibody complex C1-C2-C4-C3 forms C3 is cleaved C5-C9 forms membrane attack complex Membrane pores form, leading to lysis
What is the non-classical pathway of the complement system?
When C3 is directly activated by microbe contact
Outline three aspects of the inflammatory response
Phagocytes and other WBCs brought to site
Vasodilation
Chemical messengenrs activated (e.g. prostoglandins, histamine, complement)
What is the human leukocyte complex?
The name of the gene complex which encodes for the MHC (majot histocompatibility protein) which displays antigens on the surfaces of cells.
What do cytotoxic T cells do?
Destroy abnormal/foreign/infected cells
What do helper T cells do?
Release cytokines which stimulate the maturation/division of Tc cells, recruit macrophages and promote B cell activity
Suppressor T cells
Limit immune response
Memory T cells
Provide a rapid effective response to a second immune reaction
What is humoral immunity?
Antibody mediated immunity
What do B cells do?
Carry specific antibodies sensitised by antigens; TH cells bind to B cell antigens at MHC, recognise the antigen and secrete cytokines; B cells divide to plasma cells which secrete antibodies and memory B cells
How do antibodies eliminate cells?
Neutralise them (attach to binding sites to prevent other compounds from attaching)
Exist in fluids which coat tissues to prevent toxic cell entry into tissues
Attract phagocytic cells
Activate complement cascades
Stimulate basophils and mast cells
Link antigens together to form immune complexes
Which region of an antibody induces specificity?
The variable (top of Y) region
Which region of an antibody determines type?
The constant (bottom of Y) heavy chain region
What is the name of the sites on antigens to which antibodies may bind?
Epitopes
Describe IgG
Accounts for 80% of all antibodies
Can penetrate the placenta
Describe IgE
Attaches to basophils and mast cells (histamine)
Describe IgD
Located on B cell surface for antigen detection
