immunity Flashcards
immunity
ability of the body to defend itself against pathogen
antigen
protein/glycoprotein/carbohydrate/polysaccharide/ glycolipids recognized the body as foreign which trigger an immune response
self-antigen
product of bodys own genotype which produces a protein which do not trigger an immune response but when introduced in another body it becomes nonself
nonself antigen
foreign molecule stimulating an immune response
active immunity
antigen enters the body through infection or vaccine, provide long term immunity, memory cells produced
natural active
infection by a pathogen
artificial active
vaccine
passive immunity
antibodies injected inside the body, short term immunity, no memory cells produced
natural passive
antibodies passed through breast milk ( colostrum: first breastmilk, yellow in color, rich in antibodies ) or placenta
artificial passive
anti-venom/ injecting readymade antibodies
innate immunity
in born, non specific, no memory cells
acquired immunity
acquired during lifetime, specific, memory cells produced
opsonin
free antibodies present in plasma, not specific, increases chances of phagocytosis, this process is called as opsonisation
how is the structure of B cells adapted for its function?
many mitochondria: for ATP production ( transcription, translation, exocytosis)
large nucleus: more transcription possible
more nucleolus, more ribosome production
many RER ribosomes for polypeptide synthesis
many Golgi body for packing of antibodies into vesicles and secrete them into lymph
variable region AKA
antigen binding site
Immune response
the first 100 amino acids terminal varies in both
heavy and light chain die yo which its called as a variable region
an antibody has _ variable regions
4
where are antibodies present
in plasma, surface of pathogen
herd immunity
large proportion of people vaccinated, provides protection, transmission cycle is broken
ring immunity
vaccinate people who are exposed to infected person
T lymphocytes
they recieve specific receptors during maturation
T cells are activated under 2 conditions
Recognize an antigen inside host cell
when a macrophage engulf the pathogen and present it on the surface
T helper
it secretes all signalling molecules called cytokinesis
function: stimulates B cells to divide and form plasma cells which secrete antibodies
stimulates macrophages for phagocytosis
stimulates T cells to divide more by mitosis
promote inflammation to attract macrophages and B cells
T-Killer/ cytotoxic cells
finds infected cells/ cells displacing antigen on the surface
function: recognize antigen on the surface of infected cells and produce hydrogen peroxide to kill bodies own cells and the pathogen inside
releases perfroins that punch holes on the cell surface membrane, water enters, resulting in cell lysis
T-memory
helps in secondary immune response
T-supressor
secretes lymphokines, decreases activity of other WBC’s adter immune response
3 types of vaccines
dead germs/virus, weak/live/attentuated, vaccine
dead germs/virus
no cell division, mild immune response, less antibodies produced, overcome by giving booster doses, secondary immune response generated, antibodies produced
weak/live/attenuated
vaccine created by reducing the variance ( made harmless), undergo slow division, antigen can remain in the body for a long time, strong immune response, life long protection
vaccine
harmless virus of the same family is injected which controls the spread of diseases caused by the virus of the same family , example: cowpex virus, used to treat small pox
humoural response
pathogen is in blood/ tissue fluid/B lymph, B lymphocyte is responsible
Cellmediated immune response
antigen is inside the cell, on the cell surface,self cell with nonself antigen ( macrophage). T-lymphocytes responsible
problems associated with vaccine
malnutrition- less protein, less antibodies produced
poor response to vaccine due to defective immune system
less B cells and Tcells- bone marrow transplant, live virus can pass through faeces
problems associated with vaccine can be overcomed by
herd immunity and ring immunity
antigenic variability
change in surface protein tag/ antigen
types of antigenic variability
antigenic C shift
antigenic drift
Antigenic C shift
major change in protein tag so a new vaccine has to be used
Antigenic drift
minor change in protein tag, same vaccine can be used
antigen binding site
matches the epitopes of antigens
vary between the antibodies as they have specific amino acid sequences unique to an antigen
epitope
the part of the antigen which binds to the antibody
hinge region
gives flexibility which allows the antigen-binding site to be placed at different angles when binding to antigens ( it is not present on all immunoglobins)
Virus of toxin is blocked from the cell
Neutralisation
monoclonal antibodies
they are large quantities of identical antibodies produced by a clone of genetically identical plasma cells
they have many uses in medicine, and they are produced to be effective against a single, specific antigen
stages of the production of monoclonal antibodies
1) a mouse is injected with antigen for which the antibodies are required
2) an immune response takes place and the mouse plasma cells start to make the antibody
3) plasma cells are extracted from the mouse spleen
4) because plasma cells cannot divide, the plasma cells are fused with B cell myeloma cells using fusogen ( a chemical that makes surface cell membrane join) or polyethylene glycol (PEG)
5) the resulting hybridoma cells are separated individually and allowed to grow, divide and produce antibodies
6) some antibodies are removed and tested with the relevant antigen, to make sure they are the correct monoclonal
7) those hybridoma cells are produced the required antibodies are cultured in a large fermenter
8) the monoclonal antibodies are harvested and purified
the use of monoclonal antibodies
in the diagnosis and treatment of disease
monoclonal antibodies used in diagnosis
because the monoclonal antibodies produced from a clone of B cells are all identical, they can be used to identify macromolecules with a very high degree of specificity. for exampe they are noew routinely used for the following
1) blood typing before transfusion
2) tissue typingbefore transplant
3) identification of pathogens: using monoclonals, it is now possible to distinguish between different strains of certain pathogen which would otherwise speed up the choice of patient used
4) identifcation and location of tumors
5) detection of HIV
6) distinguis between different types of leukemia
identifying location of blood clots in the body of a person thought to have blood cancer
identifying location of a tumor
a monoclonal antibody can be used to track down cancer cells, which have different proteins in their CSA than normal body cells and can therefore be picked out by antibodies
advantages of using monoclonal antibodies than conventional ( normal) methods to diagnose disease
2 ways in which monoclonal antibodies can be used in treatment of disease
trastuzumab ( AKA herceptinTM)
Ipilimumab
infiximab
Rutiximab
difficulties in using monoclonal antibdoes in treatment of disease
ELISA TEST (ENZYME LINKED IMMUNOSORBENT ASSAY)
Steps for Elisa test
a person inhales minute particles from a v dusty env. effect on b
lymphocytes and goblet cells?
both will be more active
sequence of phagocytosis
endocytosis → phagocytic vacuole formation → digestion by lysosome
enzymes → exoyctosis
separated variable and constant regions added to cells infected w
viruses
variable regions would all bind to the same part of virus antigens!
constant region would bind to the csm
correct statements about macrophages
- more are found in tissues such as the lungs, than in the blood
- they have a role in antigen presentation
- they can engulf pathogens, dust particles, and damaged body cells
The roles of the various types of T-lymphocytes should be understood. A
major role of T cells is to
detect and destroy any normal cell that has been changed by a virus or mutation into an abnormal cell. Any graft of
tissue from a different person will have what the recipient T cells detect as abnormal cells. Therefore, T killer cells will gather at the graft site and destroy the graft. This is called rejection.
graft is like
transplant
The number of neutrophils in the blood increases during
bacterial infections and whenever tissues become inflamed and die
The number of lymphocytes in the blood increases in
viral infections and in TB.
Most of the lymphocytes that circulate in the blood are
T cells
it takes time for memory cells to
form
oth B and T cells circulate continuously between
the blood and lymph
Macrophages activated by
contact with pathogens or danger signals release cytokines (in response to infection, they can release cytokines -
this happens in the lungs)
passive immunity is not triggered by
an antigen
antibody count increases on
second exposure to antigen immediately (graph wont have like a time delay)
antigen binding site is not
only the light chains (they are located on the variable regions of both the heavy and light pp)
The typical Y-shaped antibody is formed from
two heavy chains and two light chains. Each of the four chains has a variable region
antibodies have variable
amino acid sequences for different antigens
4 pp have
2 antigen binding sites not four
plasma cells are formed only after
t-helper cells secrete cytokines
no antibodies or memory cells are produced by
the body in passive immunity
immediate protection =
artificial passive BECAUSE artificial active is not immediate, it takes time for memory cells to be formed and stuff
if someone with passive immunity to something is exposed to
that something, a primary response to that something would occur (it would take time for antibodies to form but they will form)
T-lymphocytes can secrete
cytokines. Cytotoxins are released by certain
pathogens
t lymphocytes can leave the blood and accumulate at
sites of inflammation (ig thats a symptom of infections)
monoclonal antibodies don’t work by
blocking cell signalling receptors
which trigger immune responses
antigens are not found in
blood plasma
direct cause of increase in antibody production =
plasma cells [not B memory cells even if its referring to the second exposure)
antibodies can be found on the surface of pathogens
but not on the surface of memory cells
but not on the surface of memory cells
show location of antigen
being injected w antitoxins =
artifical passive
wbs r found in
blood, lymph and lungs
lymphocytes can’t encounter
intracellular parasites
mabs can be used to
deliver drugs to specific targets
macrophages and neutrophils r present in
lymph
malaria mainly occurs in kids, and humid >
> tropical cuz tropical has rainfall (water is not stagnant)
bronchioles have a wavy
inner lining
‘production of antibodies to protect against future infections’
- true statement (idrk why) - ohh its cuz its the antibodies remembered by the memory cells
detail that can be seen =
resolution
the lowest substrate concentration will occur at the
optimum temperature. Either side of the optimum, the substrate concentration will be higher.
[opposite for product concentration]
pentose sugar not found in
nature
root cells do not have
chloroplast
if there is fixed volume of both substrate and enzyme
(ror starts off high and then decreases to zero) → ror is highest when most substrate is present
Specificity of antibody:
variable region different for each antibody
binding region to antigen;( binding site)
shape is specific and complementary to antigen ;
ref to R groups on amino acids (in polypeptide / protein) interact with antigone and antibody ;
different, sequences of amino acids / primary structures is different for each antibody and gives specificity ;
ref to, folding of the molecule / secondary structure / tertiary structure;
Explain how the function of the structure of the variable region of an antibody molecule relates to its function.
allow epitope for antigen
(two) antigen-binding, site(s) / region(s) ; A binds to / AW, antigens R active site
(shape / structure is) complementary to antigen ;
idea of specificity / AW ;
ref. to, primary structure / sequence of amino acids ;
ref. to R-groups / (amino acid) side chains, and interactions with antigen / giving specific shape
Explain the roles of the cells, A [macrophage], B [B lymphocyte] and C [T lymphocyte] in an immune response. In your answer use the terms antigen and non-self.
- foreign / AW, antigens are non-self ;
- non-self / foreign antigens, induce immune response ; AW ora
macrophage / APC (A) - phagocytosis / described ;
- cuts up / AW, bacterium / pathogen ;
- presents antigens / becomes antigen presenting cell / antigens on cell surface
B/T, cells (B and C) - antigen recognition by lymphocytes ;
- (with) complementary / specific, receptors / immunoglobulins (B) / antibodies (B) ;
- divide by mitosis ; A clonal expansion
- ref. formation of memory cells (for secondary response);
Th cells (C) - secrete cytokines to stimulate B cells ;
- cytokines stimulate macrophages ;
Tc/k cells (C) - ref. destroy pathogen / AW ;
- produce perforin / AW ;
B cells (B) - B cells become plasma cells ;
- (plasma cells) secrete antibodies ;
- AVP ; e.g.
macrophages, non-specific / faster response
ref. specificity of, lymphocytes / B and T cells
antibody variable region is the antigen binding site ;
Describe the role of T lymphocytes in fighting an infectious disease.
helper cells
1. secrete / release / produce, cytokines / lymphokines / hormones;
2. to stimulate B cells to, divide / develop into plasma cells;
3. (which) produce antibodies;
4. (and) stimulate macrophages to carry out phagocytosis / (idea of)
cytotoxic / killer T cells
- seek out / find / bind to (foreign) antigens on host cells / pathogens;
- destroy, host cells / intracellular parasites / virally infected cells / viruses;
- attach to surface of cells / ‘punch holes’ into cells;
- release toxic substances / interferons / hydrogen peroxide (into cells); R enzymes
Antigen is a foreign molecule that stimulates an
immune response.
Memory cell:
- Remains in, lymph node/blood/lymph/lymphatic system/body;
- Recognises next infection by same, antigen/(measles) virus;
- Secondary response;
- (More) rapid (than primary);
- Immunological memory;
- AVP.
Explain how active immunity differs from passive immunity.
- immune response ; A ‘immune system responds’
- to antigen ;
- clonal selection occurs / ref to B cells or T cells activated ;
- antibodies made ; A ora for passive
- memory cells produced ;
- long-lived / long-term effect / permanent ;
- not immediate / slow ; one week minimum
- passive only – antibodies removed from circulation ;
Outline how B-lymphocytes recognize antigens as non-self
antibody/immunoglobulin on cell surface
Act as receipts
Ref to antigen binding
Specific/complementary to antigens
Role of memory cells
Remain in circulation/lymphatic system
For secondary response
Faster response when exposed to the same pathogen again A faster clonal selection/clonal expansion or divide quickly/rapidly or longer lasting response
To form plasma cells
More antibodies produced
To prevent symptoms
Features of non-self antigens-
