Innate and adaptive immunity

Innate immunity (1st and 2nd Line of Defense)

born with

non-adaptive, immediate response but not very specific

intensity doesn’t change

operates continuously from the time of infection through the incubation period and until infection ends

Adaptive Immunity (3rd line of defense)

not born with

developed overtime

highly specific antibodies

remembers antigen

1st line of defense includes

skin, mucosal membrane secretions (barriers)

2nd line of defense includes

neutrophils, macrophages

complements and interferons

inflammatory response

3rd line of defense

T and B cells

Primary Lymphoid organs

cells are born

immature lymphoid cells mature

bone marrow (B cells)

Thymus (T cells)

Secondary Lymphoid Organs

Cells are activated when they encounter antigens

lymph nodes, spleen, peyer’s patches, GALT, tonsils, adenoids, appendix

Hematopoietic cells can differentiate into

other hematopoietic cells

myeloid stem cells

lymphoid cells

Myeloid stem cells can differentiate into

mast cells

myeloblast (differentiate into leukocytes)

monoblast (differentiate into monocytes that differentiate into macrophages and dendritic cells)

Lymphoid cells differentiate into

Natural Killer Cells

T cells

B cells

Cells of innate immunity

Polymorphonuclear leukocytes (granulocytes)

Monocytes

Mast cells

Granulocytes

cytoplasm contains granules

nucleus is multi-lobed

Neutrophils

largest population

strongly phagocytic

short lived (for a day)

first responders to infection

Basophils

not phagocytic

granules with histamine (inflammation)

respond to parasitic infections

allergies

Eosinophils

less phagocytic than neutrophils

target worms-secrete toxins

bilobed nucleus

intestinal parasites or blood parasites

Mast cells

granules with histamines

non-phagocytic

no bilobed/multilobed nucleus

important for inflammation

around tissues

Monocytes

are mononuclear

differentiate into dendritic cells and macrophages

Dendritic cells

high degree of function as ingesters of pathogens

antigen presenting cells

can carry phagocytosis but mainly alert adaptive immune system

Macrophages

repair/remodel, destroy pathogens

antigen presenting cells

Migrate via ameoboid motion

phagocytize pathogens and debris

show adaptive immune cells what they found

activates immune system