Immunology Flashcards

Question

How do antibodies work

Answer 1

Label invading organisms to be destroyed by other parts of immune system, this is opsonisation

Answer 2

Inherited T cells only recognise antigens as complexes with MHC molecules Peptides are presented on the surface of of antigen presenting cells in association with the MHC Allows immune cells to discriminate between normal antigens and foreign ones

Answer 3

Present on almost every cell in the body Present endogenous antigens that are synthesised in the cytoplasm on the surface Displayed to cytotoxic T cell lymphocytes (CD8+) If foreign the cell is killed otherwise it is spared

Answer 4

Only present on specialised antigen-presenting immune cells: macrophages, dendritic cells and B cells Present exogenous antigens that originate extracellularly from foreign bodies This is recognised by helper T cell lymphocyte (CD4+) The binding stimulates development of antibody-producing B cells against the antigen

Answer 5

Autoimmunity Hypersensitivity reactions Immunodeficiencies

Answer 6

Membrane attack complex produced to stab at invading pathogens Produce anaphylatoxins Prime pathogens for phagocytosis by macrophages and neutrophils (opsonisation)

Answer 7

Classical Lectin or mannose-binding Alternative

Answer 8

Activated by antigen-antibody complexes Complement factors are serine proteases Limited proteolysis

Answer 9

Involves mannose-binding lectin which binds sugars (mannose) found on the surface of pathogens but not on mammalian cells MBL binds with MASP 1 and 2 which activate C2 and C4, rest of pathway is as it was in classical

Answer 10

Yeast such as Candida albicans Viruses such as HIV and inluenza A Bacteria including Salmonella and Streptococci Parasites such as Leishmania

Answer 11

Involves auto-activation of C3 to C3a and C3b which occurs constantly at a very low rate Upon contact with bacteria auto-activated C3b binds factor B and properdin which rapidly activates more C3 and activates C5

Answer 12

C3a, C4a and C5a By-products of C3-5 during complement activation Trigger degranulation of endothelial cells, mast cells and phagocytes Cause smooth muscle contraction and enhance vascular permeability C3a and C5a also act as chemoattractants; they attract and activate neutrophils

Answer 13

C3b renders bacteria more susceptible to phagocytosis C3b is cleaved to iC3b on the bacterial surface The macrophage cell membrane contains receptors for iC3b, facilitating phagocytosis of the bacteria by the macrophage

Answer 14

Become hyperactive when stimulated by IFN-y and lipopolysaccharide (LPS) produced by gram-negative bacteria Hyperactive macrophages stop proliferating, become larger and increase they rate of phagocytosis Hyperactive macrophages produce cytokines: tumour necrosis factor (TNF) which can kill tumour cells and virus-infected cells, and interleukin-1 (IL-1)

Answer 15

Resting Primed Hyperactive

Answer 16

B-cell matures into plasma cell which allows for production of large quantities of antibody

Answer 17

Monocytes Macrophages B cells Dendritic cells

Answer 18

Helper: Activate B cells, activate phagocytes and help other T cells Killer: cytotoxic T lymphocytes, effective at attacking viruses Regulatory: not fully understood, regulate against self destruction

Answer 19

CD3 is associated with T cell receptor to make the CD3/TCR complex CD4: helper CD8: cytotoxic

Answer 20

Glycoprotein present on cell surfaces that help differentiate self from non-self Plays crucial role in T cell activation ``` MHC II (helper) MHC I (cytotoxic/ killer cells) ```

Answer 21

Th1: activate cell mediated immunity Th2 are responsible for antibody production

Answer 22

Occurs when self tolerance against a body antigen is broken

Answer 23

``` Organ specific: Thyroid disease Type 1 diabetes Pernicious anaemia Some skin conditions ``` Non-organ specific: Systemic lupus erythematosus (SLE)

Answer 24

T- cells become temporarily unresponsive to all signals due to lack of co-activation