principles of immune response

Question 1

principle features of innate immune response

Answer 1

first line of defence, pre-formed from birth (germ-line encoded)/rapidly synthesised receptors, independent of previous exposure, rapid reaction, doesn’t adapt so no memory, recognition based on sensing of common molecular patterns e.g. toll-like receptors

Question 2

what two types of components are present in the innate and adaptive immune responses

Answer 2

cellular and soluble

Question 3

advantage of innate immune response

Answer 3

rapid and effective response (minutes to hours) as many cells express same receptor

Question 4

disadvantage of innate immune response

Answer 4

limited receptor diversity so some pathogens not recognised

Question 5

3 functions of innate immune response

Answer 5

destroys invading nucleic acids in cytoplasm; activates inflammatory pathways (signals location of damage/infection for recruitment of cells); cooperates with and directs adaptive response

Question 6

innate immunity: 2 anatomical barriers and description

Answer 6

skin (mechanical barrier, acidic environment), mucous membranes (secretions trap microbes, cilia expel)

Question 7

innate immunity: 3 physiological barriers and description

Answer 7

high body temperature (fever), low pH (acidic pH of stomach destroys pathogens), chemical mediators (lysozymes, interferons, complement proteins)

Question 8

innate immunity: 7 cell types and function

Answer 8

neutrophil (phagocytosis), eosinophil (phagocytosis, granule release, defence against parasitic infections, help B cell responses in GALT to produce IgA), basophil (granule release, act as APC in Th2 immunity), monocyte/macrophage (phagocytosis, killing, cytokine release, APC), mast cell (granule release, pro-inflammatory), dendritic cell (APC), natural killer cell (lysis of infected cells)

Question 9

innate immunity: timescale

Answer 9

much quicker; image from immunology introduction

Question 10

principle features of adaptive immune response

Answer 10

consists of T and B cells; B: BCR recognises intact antigen, secrete soluble antibodies, can cause opsonisation (complement system or neutralisation); T: recognise sequences of digested antigen peptide by APCs using MHC I or II; can form memory; millions of receptors generated by random recombination of gene segments; requires priming (adaption to exposure)

Question 11

effector responses of adaptive immune response

Answer 11

cellular immunity (lymphocytes) and humoral immunity (antibodies)

Question 12

advantage of adaptive immune response

Answer 12

massive receptor diversity

Question 13

disadvantages of adaptive immune response

Answer 13

takes time to clonnaly expand cells expressing receptor, random recombination can cause autoimmunity

Question 14

5 cell types of adaptive immune response

Answer 14

lymphocytes, basophils, mast cells, dendritic cells, natural killer cells

Question 15

adaptive immunity: central process of clonal selection

Answer 15

lymphocytes that meet recognisable antigen will proliferate and survive to become effector lymphocytes; all others (naïve polyclonal) die out; when antigen removed, most lymphocytes die out; some survive as memory cells, so re-exposure to previous antigen leads to more rapid and effective secondary immune response

Question 16

adaptive immunity: timescale

Answer 16

much slower; image from immunology introduction