Adverse immune reactions (year 2)

Question 1

what are the four types of adverse responses?

Answer 1

tolerance or breakdown or tolerance
autoimmunity
hypersensitivity
transplantation

Question 2

what is tolerance?

Answer 2

state of unresponsiveness to a particular antigen

Question 3

when is tolerance useful?

Answer 3

essential to prevent immune reactions to the bodies own tissue

Question 4

what cells must show tolerance and where is this generated?

Answer 4

T cells generated in the thymus

B cells removed by bone marrow if they are self-reactive

Question 5

what occurs if tolerance isn’t selected for?

Answer 5

autoimmunity

Question 6

what is autoimmunity?

Answer 6

loss of self/non-self discrimination in the immune responses causing damage to host tissue

Question 7

what may induce autoimmunity?

Answer 7

exposure of hidden antigens
new epitope formation
cross reactivity with microorganisms 
viral induction
immunoregulation deficiency
damage to immunologically privileged sites

Question 8

name some immunologically privileged sites

Answer 8

brain, reproductive tract, eye, bile ducts

Question 9

name two systemic autoimmune diseases

Answer 9

systemic lupus erythesmatosus

rheumatoid arthritis

Question 10

what are the 4 types of hypersensitivity?

Answer 10

type 1
type 2
type 3
type 4

Question 11

what is a type 1 hypersensitivity?

Answer 11

atopy - allergic condition

IgE is produced to an antigen

Question 12

describe how a type 1 hypersensitivity comes about

Answer 12

can be from an issue with class switching from IgM to IgG/A that goes wrong and switches to IgE
 IgE binds to mast cell stimulating histamines and inflammation

Question 13

what is a type 2 hypersensitivity?

Answer 13

when antibodies bind to antigens on host cells

Question 14

what causes tissue damage during type 2 hypersensitivities?

Answer 14

phagocytosis and complement

Question 15

give an example of when a type 2 hypersensitivity may occur?

Answer 15

blood group mismatch

foals RBCs leak into mares circulation, mare forms antibodies, foals ingests these antibodies in colostrum

Question 16

what is a type 3 hypersensitivity?

Answer 16

immune complexes form/deposit on host tissue

Question 17

why do type 3 hypersensitivities occur and what is the outcome?

Answer 17

due to an excess of antibody

this activates complement and cause granulocytes to release enzymes

Question 18

give an example of type 3 hypersensitivity

Answer 18

glomerulonephritis

immune complexes are deposited in the glomerulus

Question 19

what is type 4 hypersensitivity?

Answer 19

T cell mediated so doesn’t involve antibodies

Question 20

how does a type 4 hypersensitivity occur?

Answer 20

primed T cells respond to chronic antigen load by production of cytokines which attracts and activates macrophages causing damage to the tissue

Question 21

give an example of when a type 4 hypersensitivity is used

Answer 21

TB testing

Question 22

what is the main cause of transplant rejections?

Answer 22

differences in MHC between donor and host

Question 23

what are the four types of transplant?

Answer 23

autograft
isograft
allograft
xenograft

Question 24

what is an autograft?

Answer 24

from the same animal

Question 25

what is an isograft?

Answer 25

from a genetically identical animal

Question 26

what is an allograft?

Answer 26

from the same species

Question 27

when is a xenograft?

Answer 27

from a different species