antibodies Flashcards
(16 cards)
what are plasma cells
clones of B lymphocytes
what are antigens
usually proteins or glycoproteins on the plasma membrane of a cell which can be detected as foreign by the immune system
specific to an organism (due to receptors)
what are antibodies
-immunoglobulins
-complex proteins produced by plasma cells which are complementary to a particular antigen
what do antibodies consist of
4 polypeptide chains (2x light and 2x heavy)
3 ways which antibodies can work
1-oponisation
2-agglutination
3-anti-toxins
how do antibodies work through oponsisation
-antibody molecule has 2 binding sites and end that can stimulate phagocytosis
-pathogen with several antigens on surface
-oponisation: end of antibody stimulate phagocytosis
how do antibodies work through agglutination
by using each binding site to bind to a different pathogen the antibodies cross line (getting “stuck” together) pathogens into a big clump which is non-infective and easily phagocytosed
why does agglutination make pathogens non-infective and easily phagocytosed
-non-infective = stopping functions like entering cells
-easily phagocytosed = allow multiple to be engulfed at once
how do antibodies work through anti-toxins
-some antibodies work as antitoxins by binding to toxic molecules and make them harmless to host
primary response characteristics (n of times body has encountered, speed of response, concentration of antibodies in blood, type of cells activate and if symptoms occur)
n of times body has encountered- the first encounter
speed of response- a few days for antibodies number to rise
concentration of antibodies in blood- enough to combat infection then rapidly drops
type of cells activate-b and t lymphocytes
do symptoms occur-yes
secondary response characteristics (n of times body has encountered, speed of response, concentration of antibodies in blood, type of cells activate and if symptoms occur)
n of times body has encountered- the second encounter
speed of response- rapid
concentration of antibodies in blood-higher than primary
type of cells activate- B and T memory cells
do symptoms occur-no
parts of an antibody
-light polypeptide chains
-disulphide bridges
-heavy polypeptide chains
-constant region
-hinge region
-variable region
what is the constant region
the same in all antibodies
-may have a site for easy binding of phagocytic cells
-allow binding to receptors
role of disulphide bridges
to hold the polypeptides together
role of the variable region
-a specific shape to the shape of the antigen
-variable region forms antigen binding sites which are complementary to a particular antigen
what is the purpose of the hinge region
to allow flexibility so molecule can grip more than one antigen
