lg M (early phase)
lg G (late phase)
lg G (early and late phase)
shorter lag phase
longer static phase and decline phase
higher antibody titer
stronger affinity of antibody
A single progenitor cell gives rise to a large number of lymphocytes, each with a different specificity
Removal of potentially self-reactive immature lymphocytes by clonal deletion
Pool of mature native lymphocytes
Proliferation and differentiation of activated specific lymphocytes to form a clone of effector cells
T cell-dependent• Cooperation of T-cells
Antibody cell is triggered when it encounters matching antigen
2.The B-cell engulfs the antigen and digests it
Displays antigen fragments bound to its unique MHC molecules
The helper T cell binds to the antigen-MHC class II complex and is induced to release cytokines that induce the B cell to divide rapidly
T cell-independent• Do not require T-cells
Resting of B cell
Encounter with antigen
Stimulate B cell gives rise to antibody- secreting plasma cells
B cell proliferates and differentiates
Crosses placenta to protect fetus
trigger release of histamines from basophils and mast cells
Length of constant region
Number of mers
Increase efficiency of phagocytosis
• Prevent binding of exotoxin, virus and bacteria to the cell
• Attaches to multiple cells making a clump
• Antigen covered with antibodies and bind to Fc receptors of phagocytes
Activation of complement
Increase efficiency of inflammation
Increase efficiency of phagocytosis
(First line defense)
Aim: Keep viruses, bacteria, parasites, & other foreign particles out of the body / limit their ability to spread & move through the body.
Non-specific defense mechanisms.
First and Second line of defense.
Activated immediately by the presence of antigens or pathogens.
: Skin, chemicals in blood, cilia, gastrointestinal tract, respiratory tract, nasopharynx, eyelashes.
: mucous, bile, tear, sweat, saliva, gastric acid, other secretions.
: Release of chemicals from the white blood cells into the blood or affected tissues will increase the blood flow to injury or infection area, leads to redness, warmth and swelling.
: An immune response that marks pathogen for destruction and punctures pathogen's cell membrane.
Non-specific cellular responses
Cells of Innate Immunity
Phagocytes: circulate throughout body, engulf and destroy non-self substances.
roam outside the blood circulatory system
release cytokines to recruit other cells to infected area.
Mast cells: vital for wound healing and defense against pathogens via inflammation with the help of histamine.
Toxic granules to bacteria and fungi by inhibiting their proliferation and die.
Produce fibres to trap bacteria prevent spreading.
Eosinophils: kill bacteria and parasite by secreting toxic proteins and free radicals, attach and help immobilize parasites, may cause tissue damage during allergic reaction.
Basophils: sectrete histamine and attack multicellular parasites.
Natural killer cells: release enzyme to destroy outer membrane of infected cells, destroy infected host cells to cease the spread of infection.
Dendritic cells: identify threats and act as messengers for the rest of immune system by antigen presentation.
Opsonization: A process in which foreign particles are marked for phagocytosis.
Chemotaxis: Attraction and movement of macrophages to chemical signal.
Cell lysis: Destruction of cell membrane.
Agglutination: Pathogens are clustered together by antibodies, so immune cells can attack and weaken infection.
JUST IGNORE THIS!!!!!!!
eg. You get the flu
It is resistance to disease possessed by an
Nature has given this type of immunity to certain individuals, species against certain disease.
eg. Some individuals are most resisting to certain infections than other.
lifelong for some diseases
(chicken pox, measles).
the foreign antigen enter the body naturally and trigger
- B cells
Cell mediated response
get immunity ourselves / resistance developed as a result of antigenic stimulus.
not by deliberate exposure
exposed to the
pathogen that causes the disease.
only lasts a
few weeks or months.
protect until infants have ability to produce own antibodies.
pass from a mother to fetus through the
confer immunity to the infant.
lasts 4 to 6 months after birth.
components which help in
Oligosaccharides and mucins
adhere to bacteria and viruses
prevent the attachment to host cells.
bind with iron
unavailable to most bacteria;
B12 binding protein
to deprive bacteria of needed vitamin B12;
that promotes the growth of
i) Lactobacillus bifidus,
ii) normal flora in the gastrointestinal tract of infants (harmful bacteria)
that increases the antimicrobial activity of macrophages
helps repair tissue damage from infection in the gastrointestinal tract;
a cytokine that enhances the activity of certain immune cells;
Hormones and growth factors
that stimulate the baby's gastrointestinal tract to mature faster and be less susceptible to infection;
to break down peptidoglycan in bacterial cell walls.
Definition: Adaptive response of host to specific pathogen or antigen.
it is an immunity that an organism develops during life time.
develop after exposure to antigens.
Non reactivity to self.