adaptive immunity

Question 1

two things adaptive immunity need

Answer 1

antigen( includes microbes) and innate immune response (APCs + complement system)

Question 2

two types of adaptive immunity

Answer 2

both- respond to microbes and non-microbes, can distinguish between different ones (unlike innate)
1. Humoral Immunity
Mediated by antibodies; the principle defense against extracellular microbes and toxins esp those on mucosal surfaces and in the blood from gaining access to and colonizing body tissues
2. Cell-mediated Immunity (cellular immunity)
Mediated by specific T lymphocytes and defends against intracellular microbes (i.e viruses)

Question 3

what is an antigen?

Answer 3

A substance that elicits an immune response from the host
Include the components of the microbial world
Bacteria
Fungi
Viruses
Protozoa
Parasites

nonmicrobial: examples :Plant pollens, Poison ivy, Insect venom, Transplanted organs

Question 4

epitope

Answer 4

also called antigenic determinants
small pieces of antigen (broken down b/c complex). immune system recognizes these epitopes.
–immunologically active sites on bacteria’s surface
–engulf, tag, spit out

Question 5

hapten

Answer 5

small compounds attach to larger compound (protein) to function as an antigen (ex/ allergic responses to poison ivy protein)

Question 6

antibodies and immunoglobins: what are they and what are the classes?

Answer 6

Antib. or immunoglobulin-secreted proteins of B lymphocytes that function as antigen receptors for B cells or as effector molc of the humoral immune response. There are 5 classes: IgG, IgA, IgM, IgD, and IgE

Question 7

order of response by antibodies/immunoglobins

Answer 7

GAMED
infected: 1st on the scene is M, second is G
A- in secretions (i.e.sputum)
E- in worm infestations and allergies- binds to mast cells and basophils= histamine
D- receptors to B lymphocytes

Question 8

APCs (antigen presenting cells): function and two types

Answer 8

They engulf foreign invaders; process into epitopes; display them on their own cell membrane; alert the Lymphocytes

1. Macrophages
   Cluster in connective tissue and in organs
   Liver= Kupffer cells
   Nervous system= microglial cells
2. Dendritic cells
   Found in most tissues where antigen enter the body
   Skin= Langerhans cells

Question 9

cells of adaptive immunity

Answer 9

1. lymphocytes: Tcells and B cells (have specificity, diversity, memory, and self-non-self recognition which is critical for adaptive immunity)
2. MHCs: Major histocompatibility complex molecules

Question 10

upon recognition, what do T and B cells do?

Answer 10

divide to form populations or clones of cells that continue to differentiate into effector and memory cells.
B: antiB binds to Bcell receptor=plasma cells –> produce antibody (w/ specificity)
T: helper Ts –>activate macrophages–> eat pathogens
cytotoxic Ts: kill cells infected w/ pathogen

Question 11

MHCs (major histocompatibility complex molecules): two classes

Answer 11

molecules on surfaces that help ID what type of cell and antigen are present
CD8- cytotoxic- only activated by MHC1
CD4- helper T- needs MHC 2 (“b/c 4 is 1/2 of eight”- to remember)

MHC1
On all nucleated cells
Viral particles associate with MHC I on cell surface
Associated with cancer cells too

MHC2
on immune cells, APCs, macrophages, B cells
-epitopes + MHC II molecule on cell membrane
-then direct others by the release of cytokines

Question 12

clusters of differentiation (CD) and CD4 role

Answer 12

Lymphocytes distinguished by surface proteins and the “clusters of differentiation” on their surface
Protects against viruses, cancer and intracellular bacteria
Can only recognize membrane bound antigens

CD4 helper T cell:orchestrates entire immune response
activated by APCs
Attaches to MHC II receptors + releases cytokines to…
-Stimulate B cells–> Plasma cells + Memory B cells
-activate cytotoxic T cells to get the MCH I targets
-Stimulate T helper memory cell

Question 13

CD8, CD4 + CD25

Answer 13

CD8 cytotoxic T cell-Kill cells that have been damaged from within. They show different receptors (MHC I) which signal Tc cells to kill them
–injecting preformed cytotoxic proteins into target cells which triggers apoptosis
CD4 + CD25 regulatory T cells
Suppress immune responses by inhibiting the proliferation of other potentially harmful self-reactive lymphocytes

Question 14

granzymes

Answer 14

granzymes: “killer grandma”- go through plasma membrane of infected cell- makes holes, degrades integrity of infected cell, kills it/explodes

Question 15

4 membrane receptors that can identify B cells

Answer 15

Immunoglobulin that functions as antigen receptor
Class II MHC proteins
Complement receptors
Specific CD molecules

Question 16

if you have intact immune system: every time Bcells see antigen- they make…

Answer 16

a plasma cell, memory Bcell and antibody)

Question 17

possible outcomes from Bcell activation: antigen to antibody

Answer 17

Antigen-antibody complexes
Agglutination or clumping of cells
Neutralization of bacterial toxins and viruses (CD8)
Lysis or destruction of pathogens or cells
Adherence of antigen to immune cell (Bcell, Plasma, AntiB)
Facilitation of phagocytosis (macrophage, dendritic)
Complement activation (IL, INF, etc)

IDEALLY- all result in cell death of offender

Question 18

primary and secondary immune response

Answer 18

Primary when antigen is first introduced

Secondary occurs with subsequent exposures

Question 19

transfer of immunity from mom to infant

Answer 19

Maternal IgG Ab cross the placenta during fetal development and remain functional for the first few months of the baby’s life (usually gone by 6 mo)

• Most of IgG transferred in the last few weeks of gestation
• Because of this transfer, an infant born to an HIV pos mom will have a positive HIV Ab test, although the child may not be infected with the virus
• Cord blood does NOT contain IgM or IgA typically
• IgA is transferred to the baby through colostrum via breastfeeding

Question 20

elderly immune response, decrease in what specific cells?

Answer 20

CD4 and CD8 T cells