Looks like no one added any tags here yet for you.
1st line defense
skin, mucous membranes, and antimicrobial substances
2nd line defense
slow or contain infections - inflammation, fever, phagocytes, NK cells
3rd line defense
lymphocytes, memory component
innate (non-specific)
non-inducible ability to recognize and destroy an individual pathogen or its products
does not require previous exposure to a pathogen or its products
external barricades and internal defenses
adaptive (specific)
acquired ability to recognize and destroy a particular pathogen or its products
dependent on previous exposure to a pathogen or its products
directed toward an individual molecular component of a pathogen (antigen)
takes longer to activate but keeps record
antigen
an individual molecular component of a pathogen (what our antibodies bind to)
natural host defense
the ability of microbes to cause disease Aries between species (ex. HIV can’t be given to dogs)
infection site and tissue specificity
different pathogens invade different tissues
route of infection is crucial
Microbiome
normal microbiota helps host resist pathogens, particularly on the skin and in the gut
sometimes called probiotics
physical barriers
limits the ability of the microbe to attach or replicate in tissue
(ex. skin, mucous membranes, fluid)
competitive exclusion
our body’s good bacteria fights for a spot in our body
typically wins over pathogens which then protects us
chemical barriers
usually destructive to microbes
(ex. sebum, earwax, gastric juice, urine, etc.)
skin
physical barrier
1st line
epidermis, shedding of top layers
dry, salty, & acidic plus competitive exclusion
mucous membranes
physical barrier
secretion of mucous
tears and saliva - help dilute and wash away microorganisms before infection can occur
bodily fluids
physical barrier
earwax, urine, vomiting, defecation, and diarrhea all help protect our body
sebum
chemical barrier
inhibits growth of bacteria, viruses, and fungus via antimicrobial peptides, slightly acidic
oil
perspiration
chemical barrier
helps cool skin and contains lysozyme
lysozyme
chemical barrier
enzyme that breaks down peptidoglycan
earwax
chemical barrier
physical barrier, but also helps drop pH of the ear canal
saliva
chemical barrier
begins to break down starches (amylase)
has lysozyme, uric acid, and also contains IgA
gastric juice
chemical barrier
pH range of 1-3
found in stomach
urine
chemical barrier
contains lysozyme
is acidic (pH6)
found in bladder
vaginal secretions
chemical barrier
mucus inhibits microbial attachment
L. acidophilus creates an acidic pH range inhibiting growth
found in females
probiotics
lactobacillus, fifidobacterium, and saccharomyces are 3 common ones
alter pH and oxygen concentrations to inhibit other bacteria
block pathogenic bacterial effects by producing bactericidal substances
hematopoiesis
production of blood cells and platelets from pluripotent stem cells
neutropenia
low number of immune cells
neutrophilia
high number of immune cells
basophils
patrol system for foreign bodies
upon recognizing a microbe, the cell secretes histamine to recruit more immune cells
histamine causes inflammation
mast cells
in tissue looking for foreign bodies
very similar to basophils but do not patrol - stay within tissues (usually CT under the skin & mucous membranes)
also release histamine and other chemical to induce inflammation
eosinophils
target parasitic infections and play a role in allergic reactions
attach to parasites and discharge peroxide ions to destroy then
seem to be increased in # due to allergies
neutrophils
most numerous
1st to be recruited to site of infection
phagocytize & destroy bacteria/foreign bodies - use lysosomes
destroy bacterial toxins in body fluids
only live a few days
monocytes
in the blood - macrophages in the tissues
better at killing variety of pathogens
live a few months
present pieces of dead microbes on surface (antigen presentation) and a larger immune response occurs
present antigens to T-cells
fixed macrophages
residents in tissues and organs
free macrophages
roam tissues and gather at sites of infections
dendritic cells
phagocytize microbes
also present pieces of dead microbes on surface to activate adaptive immune response
natural killer cells
primarily kill virally infected cells, but can help kill cancerous cells and bacteria
recognize cells that do not display MCH 1
MCH
major histocompatibility complex
granzyme
an enzyme that induces programmed cell death (apoptosis)
perforin
poles holes in (perforates) the target membrane
1 - Recognize the microbe
mast cells and fixed macrophages are the 1st to respond, but eosinophils and basophils are close behind
2 - Recruitment
cells begin to release chemicals (cytokines) to recruit the rest of the immune system via inflammation and fever
3 - phagocytosis
fixed macrophages are 1st but are helped by neutrophils, which are recruited next and are the major phagocytic cells, free macrophages and dendritic cells to eat microbes
4 - induce complement
a cell-free system to kill and target microbes
5 - combating viruses
interferon (a type of cytokine) and dendritic cells
PAMP
pathogen associated molecular patterns
structures and molecules not found in or on the host cells
PRR
pattern recognition receptors
found on mast cells
diapedesis
release of cytokines and innate cells from blood circulation
pyrogens
fever causing cytokines
transferrins
sequester iron, keeping it away from pathogens and limiting their growth
chemotaxis
chemical signals attract phagocytes to microorganisms
adherence
attachment of a phagocyte to the surface of the microorganism
MAC
membrane attack complex
poke holes in the cell
opsonization
help phagocyte grab microbe
interferons
small cytokine proteins that are produced by virally infected cells
serve as a warning system
prevent viral replication by stimulating the production of antiviral proteins
humoral
B cells
antibodies from those B cells recognize antigens of non-self cells and mark them for destruction
mostly fight invaders outside of the cell
cellular
T cells
primarily respond to antigens after they have made their way inside a cell
involved in cytokine production attacking infections and memory cells
B cells
originate and mature in bone marrow
mature into plasma cells or memory cells
plasma cells
fight infection by producing antibodies which attach to bacteria or viruses
agglutination, enhances phagocytosis, activation of complement, neutralization
memory cells
live a long time
can differentiate into plasma cells during a subsequent infection
T cells
originate in bone marrow and mature in thymus
98% killed in the thymus (not smart enough)
all mature by the time you reach puberty
helper T cells
CD4
release cytokines and call in reinforcements
once activated - produces more helper T cells, memory T cells, cytotoxic T cells and regulatory T cells
cytotoxic T cells
directly kill bacteria or infected host cell
use granzymes and perforin
looks for antigen presented on MHC 1 on infected host cell
regulatory/suppressor T cells
stops immune response
also inhibit food allergies
memory T cells
long lived and help speed up the process during subsequent infection
leukocytes
all WBCs - mast cells, basophils, eosinophils, etc.
lymphocytes
immune cells often found in lymph nodes
primarily B & T cells, also can include NK cells
1 - antigen presentation
innate immune cells must present a piece of the microbe to T cells
2 - clonal selection and expansion
only B & T cells that recognize the antigen begin to grow
3 - release of cytokines
many different cytokines are released to induce a robust immune response
4 - killing virally infected cells
T killer cells are primed by T-helper cells and kill virally infected cells
5 - antibody release
antibodies neutralize and help with opsonization of microbes and toxins
6 - memory
memory B & T cells remember the microbe in case the host is infected again
antigen presenting cells (APCs)
engulf, process, and present antigens to lymphocytes
macrophages, dendritic cells, and B cells
antigen
protein or polysaccharide that stimulates immune system
substance that reacts with antibody molecules and antigen receptors on lymphocytes
epitopes
the actual proteins or fragments of an antigen that react with receptors (5-15 amino acids or 3-4 sugars)
MHC 1
on all nucleated cells
signals “we need help” or “i’m infected”
CD8+ or T cells
MHC 2
only certain immune cells
Signals “we need help”
CD4+ T cells
interleukins
cytokines which serve as the intermediary between leukocytes
chemokine
cytokines that induce migration of leukocytes into areas of infection
interferons
originally named for interfering with viral infections
tumor necrosis factor
cytokines named because originally seemed tumor cells were targets - involved in inflammation
hemopoietic cytokines
these aid in the control of the pathway of WBC recruitment and maturation
cytokine storm
cytokines also stimulate the production of more/other cytokines - these loops can get supercharged and can cause overproduction
IgA
found in mucous, saliva, tears, and breast milk
prevent adherence of microbes to mucosal surfaces
short-lived
IgD
part of the B cell receptor
activates basophils and mast cells
IgG
secreted by plasma cells in the blood
able to cross the placenta into the fetus
most abundant and long-lived
IgE
protects against parasitic worms
responsible for allergic reactions
IgM
may be attached to the surface of a B cell or secreted into blood
responsible for early stages of immunity
short-lived
hypersensitivity
inappropriate immune response that results in host damage
Type 1 Hypersensitivity
caused by IgE antibodies
reactions occur within minutes after exposure
often though of as an allergy
Type 2 & 3 Hypersensitivity
typically a result of IgG antibodies
occur within 24 hour of exposure
type 2
Rh factor rejection in mother of a Rh+ child
type 3
rheumatoid arthritis
type 4 hypersensitivity
result of T killer cells attack the host or T helper cells
immune system has mistakenly decided that a host protein is a foreign antigen
SCID
severe combined immune deficiency syndrome
serious, congenital deficiency of both B and T cells
AIDS
acquired immunodeficiency syndrome
caused by HIV infection that progresses and kills CD4 and T cells
immunity
the ability of an organism to resist infection
active natural
exposed to the disease
passive natural
antibodies cross placenta or breast milk (temporary)
artificial active
active immune system responses to antigen from vaccine