Intro to Immunology

Vaccination

Is immune manipulation ex. smallpox

Microbes

Live within us to obtain nutrients and protection from the environment

Commensals

Have established a non-pathogenic treaty with humans and may even offer the host an advantage.

ex. Vitamins, colicins and site protection by normal flora

Pathogen

An organism with the potential to cause disease

Bacteria

Virus

Fungi

Parasite

4 types of pathogens

Population Size & Location

With pathogens, the immune system limits

Immunological Memory

Pathogens can adapt quickly to circumvent…

ex. Flu, HIV

Epithelial cells

These cells cover all outer surfaces and line inner cavities.

Keratinized Cells

Type of cells that are physically tough and form the outer epithelium

The Innate Response

Acts upon most infections to localize and eliminate them without symptoms developing

receptor proteins; effector cells

The innate system first recognizes a pathogen is present using _______ then eliminates it by recruitment of _______ (phagocytes) and activation of complement

Cytokines

The innate system can also be triggered by these secreted proteins sent out by infected and damaged cells

Inflammation

is thus induced at the tissue level due to the activity of cells at the site of infection

The Innate Response

Heat and redness result from increased blood flow. Pain and swelling due to the influx of immune cells.
In inflammation: heat, pain, redness and swelling all result from the action of the

Response Amplification

Allows control at multiple steps.

The immune system acts in a cascade – one event triggers the next leading to

Adaptive Response

If the innate can only slow the progress of a particular infection but not clear it the ____ will be triggered. Involves lymphocytes, and adds power and specificity

Cross React (with second pathogen)

The adaptive response is specific to the individual pathogen and will not usually

Multiple Pathogens

Innate has varied receptors which bind common features in

Specific Pathogen

Adaptive has a single molecular receptor type which recognizes a

Receptor Gene Fragments

An infinite number of different adaptive receptors can theoretically be produced by cutting and splicing the transcripts from a group of

Select

Infection will ____ for only the lymphocytes which bear the receptor which recognizes the pathogen

Proliferate; Differentiate

Selected lymphocytes ____ and ____ to amplify the adaptive response

Lag; Symptoms

The clonal selection and expansion of the lymphocyte population takes time and results in a ____ between the innate and adaptive responses which we experience as ____ of disease

Memory Cells; re-exposed

Some cells from the pool of expanded lymphocytes will differentiate to form ____ which can respond rapidly and more strongly if the host is ______

Adapt

Memory only works if the pathogen fails to

Vaccination

Mimics first exposure and stimulates a primary response which leads to development of memory

Primary Response

First exposure to pathogen

Booster

Poor stimulation of the primary response may not result in adequate development of memory, it can also fade. _____ may be required to strengthen memory

Genetic Mutations

A lack of innate immunity will have serious consequences. ______ which disrupt the innate system are not well tolerated

Hematopoiesis

Cells of the immune system are generated continually through life

Pluripotent Hematopoietic Stem Cell

All cells (leukocytes, erythrocytes and megakaryocytes) arise from _____ which are self renewing though cellular division.

Bone Marrow

Hematopoiesis starts in the fetal liver moves to the fetal spleen and finally moves to the _____ where it continues throughout life. All blood cells are short lived and must be continually generated

Neutrophils, Eosinophil, Basophils

3 Types of Granulocytes; Contain reactive molecules and enzymes used to directly kill pathogens

Neutrophils

phagocytic granulocytes, first and most abundant responder in innate system, short lived, die and form puss

Eosinophil

Granulocyte; Intestinal parasites

Basophils

Granulocyte; Parasites

Monocytes

Circulate in the blood and differentiate into macrophages when they enter tissue

Macrophages

Phagocytose pathogens, dead cells and debris, and are relatively long lived

A first alert cell which secreates cytokines and chemokines to recruit other cells such as PMNs

Dendritic Cells

Sit in the tissue to survey for pathogens, once found these cells move to the lymphatics to alert the cells of the adaptive system; antigen presenting cell (APC)

Mast Cells

Reside in all connective tissue to inflammation when active

Allergic response

Natural Killer Cells

Large granular lymphocyte; Part of the innate system, involved in viral defense, secrete cytokines and interferons

B Cells

Small lymphocytes; adaptive response

Surface immunoglobulin receptors; antigen specificity

T Cells

Small lymphocytes; adaptive response

Surface T cell receptors; antigen specificity

Cytotoxic T Cells

Kill viruses and bacteria which replicate inside human cells, overlap in function with NK cell

T Helper Cells

Secrete cytokines which activate other cells of the immune system

Ex. B cell → plasma cell

Lymphoid Organs

Bone marrow, thymus, adenoids, tonsils, appendix, lymph nodes and peyers patches

Lymphoid Tissues

They line the respiratory, gastrointestinal and urogenital tracts

Primary Lymphoid Tissues

Where lymphocytes develop and mature

T & B cells arise in marrow;

B mature in marrow (Continually produced)

T cells mature in Thymus (maintained thru division)

Secondary Lymphoid Tissues

Mature lymphocytes sit waiting to be stimulated by antigen from a pathogen

B & T interaction w/ antigen in lymph node

Lymphatics

Lymph nodes lie at the junctions

Origniate in the connective tissue and form a net-work of branching and reconnecting vessels throughout the body

Collect lymph fluid which leaks from the blood and forms extracellular fluid

Lymph

Flows slowly through valves which maintain the direction of flow back to the thoracic duct where it returns to the blood

Will pool to form edema if you stop moving for extended time