-non intact skin

-through sebaceous glands

-hair follicles

-fatty acids on skin

-acidic pH of sweat

-sebaceous secretions

-hydrolytic enzymes

the acquisition of a microbe by a host

-elimination

-commensalism

-colonization 

-persistence and disease

polymorphonuclear leukocytes

monocytes

macrophages

pinocytosis- ingestion of liquid or very small particles by vesible formation in a cell 

phagocytosis- engulfment of partcle or microorgansism by white cells such as macrophages or neutrophils 

basophils

mast cells

eosinophils 

neutrophils 

o   Kupffer cells (in liver)

o   Alveolar (lung)

o   Splenic (spleen)

o   Peritoneal (free floating in the peritoneal fluid)

o   Microglial cells (nervous tissue)

o   Large granular lymph like cells which recognize the altered membranes of abnormal cells (virus infected or cancer cells)

o   NK cells are cytotoxic for these 

-induce vasodilation and contraction of smooth muscle

-act on epithelia of blood vessels to make them more permeable

-nerve stimulants(responsible for pain and itching)

-

What are some systemic inflammatory responses?

o   Fever

o   Increased white cell production

o   Increased creation of hydrocortisone and adrenocorticotropic hormone (acth) and the production of ACUTE PHASE PROTEINS 

C- reactive protein which can bind certain microorganisms and activate the complement system. Can be tested for in the lab

What are cytokines?

They are Released by macrophages

o   Increased adhesion of vascular endothelial cells, so Neutrophils, monocyte and lymphocytes can more readily stick to them.  (before extravasation)

What is chronic inflammation?

When it is impossible to remove the cause of inflammation 

it occurs from:

-chronic infection (tuberculosis)

-chronic activation of the immune response (rheumatoid arthritis)

What is fever caused by?

it is caused by many bacterial products

-endotoxins of gram neg bacteria

-fever triggerd by cytokines called "endogenous pyrogens" are produced in response to these toxins

When does acquired immunity ?

they are those in which maturation of B and T lymphs into antigen-recognizing lymphocytes occurs. 

Bcells-Bone Marrow

Tcells-Thymus gland

·      migrate into the circulatory and lymphatic system to lymphoid tissues including lymph nodes and spleen tonsils, appendix, and small intestines (peyer’s patches) 

o   These are efficient in trapping and concentrating foreign substances

o   Main sites of AB and the induction of antigen specific t cells

Name the secondary lymphoid organs

The Spleen

o   Traps and concentrates foreign material

o   Major organ where AB’s are made and released to circulation

o   Composed of white pulp (rich in lymphoid cells) and red pulp( contains many sinuses rich in RBCs and macrophages) 

What are lymph nodes?

They are small ovoid structures

-various regions in the body

-close to major lymphatic channels

-composed of: a medulla (many sinuses), a cortex (surrounded by capsule of connective tissue, and contains lympoid follicles)

·      follicle enlarges to form secondary lymphoid follicles with dense amounts of lymphs (mostly B cells) which undergoing mitosis

·      At this time B cells undergo AFFINITY MATURATION to generate clones  of cells which produce high affinity, Ag specific AB’s 

Where do antigens enter the lymphnode and what do they interact with inside the lymph node? 

they enter through the afferent vessicles

in the node, the Ags interact with macrophages, T cells and B cells which brings on an immune response

How do the AB's and lymph fluids leave in the lymph node?

through the efferent lymphatic vesicle

Where does the arterial blood enter in the spleen?

·      Diversity:

o   ability to respond to many different antigenic determinants (epitopes)

·      specificity:

o   the ability to discriminate between epitopes

·      discrimination between self and non self

o   the ability to respond only to non-self antigens

·      memory

o   the ability to recall previous contact with an Ag so later exposure leads to a quicker, stronger response 

Hematopoietic stem cells 

Heavy Chain locus a Dh chain rearranges to a Jh chain gene segment to form DJ unit

CD19 and CD10 appear on pro-B cells 

it combines with  gamma 5 gene and VpreB gene

together they function as temporary light chains (surrogate light chains)

What is the pre-b-cell receptor made up of?

heavy u chain, temp light chains, Iga(alpha) & Igb(beta)

Iga=CD79a

Igb=CD79b

do Iga and Igb bind the antigen?

the kappa chain rearranges first.

if not successful then Lambda gene rearrangement takes place

What are Kappa and Lambda?

they are the names of particular loci on a gene

loci = specific location

What happens if the lambda rearrangement is not successful?

the cell dies

What is Bruton's tyrosine kinase? (Btk)

is an enzyme which plays a crucial role in the transition of the pre B-cell to the next step. 

*involved in intracellular signaling from the pre-BCR to the nucleus of the pre-B cell*

  causes B cell differentiation to become arrested at the pre-b stage. 

What CD do immature B cell express?

CD20 

MHC cells

What happens when immature B cell interacts with self antigens on surface MHC cells?

this activates receptor editing.

the cells original Ig heavy chain is paired with a new light chain. the immature B cell makes an Ig with different specificity

What is negative selection? (involved in immature B cell)

What Ig's are found on mature B cells?

What is the final stage of development in B cells?

plasma cells

(secret abs of a single ag specificity)

What CD's are on the surface of plasma cells?

none

in the germinal centers of lymph nodes and spleen

bone marrow-

they make high levels of IgG and monomeric IgA to provide protection in the blood for later exposures

·      Plasma cells that synthesize dimeric IgA, which protects mucosal surfaces, develop where?

in mucosa-associated lymphoid tissue. (MALT)

IgD

travel to peripheral lymph nodes and GALT (gastro associated lymph tissue) 12 hours. 

·      in that reaction, memory cells and plasma cells are made. the memory cells move into tissues. the plasma cells migrate to the bone marrow

High affinity

IgM

Later responses of TD synthesis are characterized by the production of what?

antibody classes other than IgM, and also characterized by the development of long lived memory B cells and plasma cells

What do the B cells undergo in the germinal center?

1. Somatic Hypermutation- B cells with higher affinity for activating antigen are selected

2.Class switch Recombination IgM+ IgD+ B cells switches to synthesis of IgG, IgA, or IgE

Dark Zone

they form a mantle zone around the proliferating cells

What is affinity maturation 

its the inrease of production of high-affinity antibodies to a particular antigen

What are commensal bacteria?

Plasma cells close to the epithelial basement membrane of Gi and repiratory mucosa, salivary and tear glands and lactating mammary glands secrete what?

dimeric IgA,  it acts on the luminal side of the epithelial cell layer to protect the mucosal surfaces from the many pathogens that enter the body via these routes of exposure

During synthesis of IgA in the gut, where are the inductive sites located?

Galt (Gut associated lymphoid tissue, or peyer patches) lies beneath the intestinal epithelium in an area of peyer’s patches 

M cells

Dendritic cells

they are predominant in peritoneal and pleural cavities and to a lesser extent in the spleen and lymph node

most have CD5 which are not seen on any other B cells.

they are the predominate cell type in chronic lymphocytic leukemia