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