Immune System

define immunology

study of physiologic mechanisms that allow body to differentiate between self and non-self, how body reacts when non-self is encountered

define immunity

capability of body to resist pathogens from entering

define immune system

defense that protects individuals from invading pathogenic microorganisms and cancer

define pathogen

foreign to body as determined by body through self-selection of tissue

types of pathogens

bacteria, virus, protein, cancer cells

describe major histocompatibility complexes (MHC)

cell receptors that hold onto pathogens and allows immune system to see it

differentiate types of MHC

class 1 is inside the cell, class 2 is outside of the cell

which type of MHC performs phagocytosis

class 2

functions of immune system

protect from foreign substances, identify foreign material, synthesize antibodies to destroy, eliminate foreign bodies

define active immunity

natural exposure to pathogen, vaccination for pathogen

define passive immunity

transfer or immune products like antigens, can be given after exposure to pathogen

what body systems are involved in immune system

cardiovascular and lymphatic systems

describe myeloid lineage of immune cells

1. hematopoietic stem cells differentiates into lymphoid progenitor and myeloid progenitor

2. myeloid progenitor differentiates into neutrophil, eosinophil, monocyte, mast cell, basophil

3. monocyte differentiate into dendritic cell and macrophage

how to differentiate cells from myeloid progenitor cell

presence of granules and shape of nucleus

which cells defend against parasites

eosinophils, mast cells, basophils

mast cells are involved in

defense against parasites, inflammatory allergic response

purpose of dendritic cell

communicate with lymph nodes for recruitment of T/B cells

both dendritic cells and macrophages are involved in what process

antigen presentation (MHC)

describe lymphoid lineage of immune cells

1. hematopoietic stem cell differentiates into lymphoid progenitor and myeloid progenitor

2. lymphoid progenitor differentiates into B cell progenitor, natural killer cell, T cell progenitor

3. T cell progenitor differentiates into memory T cell, cytotoxic T cell, helper T cell

4. B cell progenitor differentiates into memory B cell, plasma cell

what is special about lymphoid lineage of immune cells

immune cells are more adaptive

which immune cells produce an automatic response to pathogens

natural killer cells

primary lymphoid organs

bone marrow, thymus

secondary lymphoid organs

spleen, lymph nodes, gut associated lymphoid tissue

differentiate primary and secondary lymphoid organs

primary produces immune cells, secondary readies immune cells to fight/defend

what happens in bone marrow

stem cell storage, differentiation of granulocytes and lymphocytes, differentiation of RBC, storage of plasma and memory B cells

what happens in thymus

T cell differentiation from T cell progenitor to memory, cyotoxic, helper T cells

T cell progenitor also known as

thymocyte

purpose of spleen red pulp

remove RBC, recover iron

purpose of spleen white pulp

lymph node function

blood pathogens are dealt by which organ

spleen

what happens in lymph node

immune cells meet here, antigens are presented to activate B and T cells

what happens in gut associated lymphoid tissue (GALT)

contain B cells and antibodies, associated with AIDs

differentiate innate and adaptive immunity

innate is non-specific, adaptive is specific

mechanical innate immunity of skin

epithelial cells, longitudinal flow of air/liquid

chemical innate immunity of skin

fatty acids, antimicrobial peptides

microbiological innate immunity of skin

normal microbiota

define microbiota

microbacteria already existing in body

mechanical innate immunity of gut

epithelial cells, longitudinal flow of air/liquid

chemical innate immunity of gut

low pH, antimicrobial enzymes, antimicrobial peptides

microbiological innate immunity of gut

normal microbiota

mechanical innate immunity of lungs

epithelial cells, movement of mucus by cilia

chemical innate immunity of lungs

pulmonary surfactant, antimicrobial peptides

microbiological innate immunity of lungs

normal microbiota

mechanical innate immunity of eyes/nose/oral cavity

epithelial cells, tears, nasal cilia

chemical innate immunity of eyes/nose/oral cavity

antimicrobial enzymes in tears/saliva, antimicrobial peptides

microbiological innate immunity of eyes/nose/oral cavity

normal microbiota

where are chemical barriers produced

epithelial cells

how do antimicrobial peptides work

bind to pathogens and disrupt their physical structures

how does pH affect innate immunity

changes proteins, changes in pH can kill off pathogens

how do lysozymes work

destroy cell wall of pathogens and promotes cell lysis of pathogens

soluble mediators for innate immune response

complement system, natural killer cells

cellular innate immune response

neutrophils, eosinophils, monocytes, mast cells, basophils, macrophages, dendritic cells

differentiate pathways for complement system

classical pathway activated with antigen/antibody complexes for immune system, alternate pathway activated with plasmin

effects of complement system

• release of anaphylatoxin

• release of opsonin

• release of neutrophils

• membrane attack complex

purpose of anaphylatoxin

activated mast cell degranulation to release histamines for smooth muscle contraction and increased permeability of vessels

purpose of opsonin

signal for phagocytosis

purpose of neutrophils

simply inflammatory response

purpose of natural killer cells

kill infected and tumor cells through apoptosis, travel through blood for continuous self-selection, utilize MHC

define apoptosis

programmed cell death

list of primary phagocytes

neutrophils, monocytes, macrophages

which phagocyte is most ocmmon

neutrophils

which phagocyte lasts longer

monocytes, macropages

list of secondary phagocytes

eosinophils, basophils, mast cells

what differentiates primary and secondary phagocytes

secondary are used as last resort, release granules

list of antigen presenting cells

macrophages, dendritic cells

describe antigen presentation process

1. immature dendritic cells become mature upon contact with antigen within lymphatic vessels

2. mature dendritic cells activate naive helper T cells in lymphoid organs using antigens

3. adaptive immune response takes place

describe pattern recognition process

1. pathogen invades and cytoplasmic DNA is identified by DNA detecting enzyme cGAS

2. cGAS relays pathogen associated molecular patterns to helper T cells dendritic cell

3. virus replication inhibited, immune response targeting tumor triggered

describe the adaptive immune response

more specific to pathogen and remember past responses to infection

structures involved in humoral adaptive immune response

antibodies, B cells

structures involved in cellular-mediated adaptive immune response

T cells

key difference between humoral and cellular-mediated adaptive immune responses

goal of humoral is phagocytosis, goal of cellular-mediated is lysis of infected cell

define antigen

molecules from pathogens that induce immune responses

examples of antigens

bacterial components, parasites, virus capsule, virus DNA, virus RNA, foreign tissue from transplant/transfusion, allergens, drugs

purpose of antibodies

• attack antigens

• activate complement system

• activate mast cells for anaphylaxis (allergic reaction)

• stimulate antibody-mediated hypersensitivity

which antibody is primarily involved at first exposure

IgM

which antibody is primarily involved in subsequent exposures

IgG

antibodies also known as

immunoglobulins

largest and first antibody produced

IgM

antibody that is exclusively intravascular

IgM

antibody that activates complement system

IgM, IgG

most abundant antibody

IgG

antibody most involved in passive immunity

IgG

antibody that opsonize and neutralize bacteria

IgG

antibody synthesized after IgM

IgG

antibody most dominant in body secretions

IgA

antibody that prevents antigen from entering tissues

IgA

least concentrated antibody

IgE, IgD

antibody attached to mast cells and basophils

IgE

antibody that increases number of eosinophils

IgE

antibody most involved in allergic responses

IgE

antibody most involved in present of parasites

IgE

antibody presented on surface of B cells

IgD

general functions of antibodies

• neutralization

• enhance opsonization

• activate complement system

define neutralization

antigens are inactivated by antibodies

source of antibodies

B cells

where do B cells originate

bone marrow

where do B cells differentiate

B cells

purpose of plasma cells

release antibodies

where to find plasma cells

blood vessels

how do plasma cells work

1. B cell receptor binds to antigen

2. receive signal from helper T cell

3. becomes plasma cell

4. releases antibodies to attach to same antigen that it had attached to