Lecture 1-2

Describe the first “vaccination” by Edward Jenner and its testing process

Took the pus of cowpox buboes and infected a boy with it. He fell sick for a few days, then recovered. Then, the boy was infected with a scab of a smallpox patient, to which he was immune to.

Describe Pasteur’s goose neck flask experiment.

What is herd immunity?

Introducing a case of a disease to a well-vaccinated community will lead to very few contracted cases.

Identify the study first linking autism to vaccines.

1998 Lancet study

Describe the reasoning behind the conclusion of the 1998 Lancet study

8/12 children presented with autism days after receiving a MMR vaccine. Wakefield, the person behind the study, postulated that the vaccine caused GI inflammation tht.at allowed translocation of usually non-permeable peptides to the bloodstream where they affected development

Why was the 1998 Lancet study invalid?

All of the 12 cases contained fabricated information. The study was eventually retracted

What evidence supports that thimerosal, an additive used in vaccines, doesn’t cause autism?

Cases of autism in children have continued to rise since thimerosal was removed from all childhood vaccines in 2001.

Humoral immunity combats pathogens using:

Antibodies

What is passive immunity? Give an example.

temporary protection against a disease provided when a person receives pre-made antibodies from another source rather than making them. EX: immune serum/antiserum

What is active immunity? Give an example.

When your own immune system makes antibodies and memory cells after it meets a foreign germ or antigen. EX: Vaccines

What is pathogenesis?

The process by which pathogens induce illness in the host

Molecules on outer surface of cell membrane that identify them as friend or foe

Antigens

Activation of innate immune responses produces _____ ________ which stimulate and direct ________ immune responses.

signaling molecules; adaptive

Humoral responses use ___ lymphocytes while cell-mediated responses use ___ lymphocytes.

B; T

Function of antibodies?

Fits into matching antigen and prevents it from entering healthy cells or marks it for destruction by other immune cells

The ability of the adaptive immune system to respond much more swiftly and with greater efficiency during a second exposure to the same pathogen

Immunologic memory

Name 2 important abilities of stem cells.

(1)the ability to regenerate or “self-renew”

(2)the ability to differentiate into all diverse cell types.

What 2 types of progenitors do HSCs differentiate into?

Myeloid progenitor and lymphoid progenitor

Function of innate immune system:

The first to respond to a pathogen and communicate the presence of the pathogen to the lymphocytes

Which lineage of cells make up the innate immune system?

Myeloid

Name the 2 main categories of monocytes.

Inflammatory and patrolling

These cells enter tissues quickly in response to infection/damage, recruit other cells through the secretory pathway, and are phagocytic.

Inflammatory monocytes

These cells crawl slowly along blood vessels and provide a reservoir for tissue-resident monocytes in the absence of infection

Patrolling monocytes

When monocytes enter tissues, they differentiate into(2 possible things):

Macrophages and dendritic cells

3 functions of macrophages:

1. repair/remodel (trash collectors)

2. destroy pathogens via phagocytosis

3. present antigens for T lymphocytes

True or false: macrophages can bind to certain classes of antibody.

True

What is opsonization?

bacteria are targeted for destruction by a phagocyte

These cells act as messengers between the innate and the adaptive immune systems. They are highly phagocytic and are the most potent antigen presenting cells.

Dendritic cells

Outside lymph nodes, immature dendritic cells capture:

Foreign antigens

What are 3 ways immature dendritic cells capture antigens?

Phagocytosis, pinocytosis, receptor mediated endocytosis

Once monocytes process antigens, they travel to the ______ _____ where they present the antigen to _____.

Lymph nodes; naive T cells

These cells have multi-lobed nuclei and cytoplasm with granules that are released in response to contact with pathogen

Granulocytes

Granulocytes are part of the _____ immune system.

Innate

The majority of circulating leukocytes are what kind of cell?

Neutrophils

These cells are phagocytic, first responders(especially to infection), and amplify inflammatory reactions.

Neutrophils

Process in which the number of circulating neutrophils increases significantly in response to infection.

Leukocytosis

Non phagocytic granulocyte with an important role in parasitic infections and allergies. Contains histamine and heparin.

Basophils

Function of histamine

Vasodilator, promotes blood flow to tissues.

Function of heparin

Anticoagulant, prevents blood clotting

Granulocyte involved in inflammation/allergies, wound healing, and angiogenesis. Contains histamine and heparin.

Mast cells

Mast cells express a high-affinity receptor for which antibody?

IgE

Motile phagocytic cells that can migrate from the blood into the tissue spaces. Protects against parasites.

Eosinophils

Function of eosinophil cationic protein (ECP):

Released from Eosinophil granules and creates toxic pores in the membranes of target cells allowing potential entry of other cytotoxic molecules to the cell

What do megakaryocytes make?

Platelets

What do erythroid progenitors make?

Erythrocytes aka red blood cells

What are lymphocytes?

The principle cells in the adaptive immune response.

Identify the 3 main categories of lymphocytes.

B lymphocytes, T lymphocytes, natural killer cells

How do we differentiate between T cells and B cells?

They express different surface proteins and different antigen specific receptors.

Where do B lymphocytes mature?

Bone marrow

What receptor do B lymphocytes display?

B cell receptors

Activated B cells differentiate into effector cells known as:

Plasma cells

What are plasma cells?

White blood cells that are specialized to secrete large amounts of antibodies to fight infection

T cells initially develop in the _______ but migrate and finish development in the _____.

Bone marrow; thymus

What type of antigens do T cells recognize?

Processed pieces of antigen bound to cell membrane proteins called major histocompatibility complex (MHC) molecules

Identify the 2 cell types T lymphocytes are divided into.

T helper(TH) and T Cytotoxic(TC)

T helper cells display ____ membrane glycoproteins and recognize antigens in complex with MHC class ___.

CD4; II

T helper cells display ____ membrane glycoproteins and recognize antigens in complex with MHC class ___.

CD8; I

This MHC class occurs on all nucleated cells; (all cells but red blood cells)

When recognized, the cell gets destroyed

MHC I

This MHC class occurs on macrophages, B cells, and especially dendritic cells. These proteins proliferate memory T cells, recruits other cells

MHC II

How do natural killer cells differ from T and B cells?

NK cells don’t express antigen specific receptors and are part of the innate immune system

How does Fluorescence Activated Cell Sorting work?

Tags cells with fluorescent antibodies, passes them through a laser. A vibrating stream separates the cells based on their fluorescence and sorts them into separate tubes.

Name the primary lymphoiSpld organs

Thymus, bone marrow

Name the secondary lymphoid organs

Spleen, lymph nodes

What effector cells do B cells differentiate into?

Plasma cells

What effector cells do T cells differentiate into?

T cytotoxic or T helper

Where does differentiation into effector cells take place?

The follicles of secondary lymphoid organs

Name 2 functions of the lymphatic system.

Recycling fluids lost from cardiovascular system

Transporting pathogens to lymph nodes

Lymph capillaries form a network between:

cells of connective tissues

Name 3 things lymphatic capillaries pick up from surrounding tissues.

interstitial fluid, proteins, immune cells

Where does the lymphatic fluid(lymph) empty into from the lymph capillaries?

Lymphatic vessels

What are lymph nodes?

Encapsulated, bean-shaped structures connected to both blood vessels and lymphatic vessels

Name the layers of the lymph nodes from outermost to innermost.

Cortex, paracortex, medulla

This layer of lymph node is made up of mostly B cells, macrophages, and dendritic cells arranged in follicles.

Cortex

This layer of lymph node is made up of T cells and dendritic cells that migrated from tissues to the node.

Paracortex

This layer of lymph node is where lymphocytes exit the lymph node via outgoing (efferent) lymphatics

Medulla

B cells respond to specific signals that draw them to the:

lymph node follicle

B cells depend upon ________ cells for guidance.

follicular dendritic cells (FDCs)

What is the function of the fibroblast reticular cell conduit system (FRCC)?

Guides T-cell movements through the lymph node paracortex and increases the chances of T cells finding their MHC-Antigen match

What does the spleen do?

filters the blood, traps blood-borne antigens, and removes and destroys old, damaged, or fragile RBCs

Where are RBCs compartmentalized in the spleen?

Red pulp

What is the function of the marginal zone?

Antigen is trapped there, processed by dendritic cells, and taken to white pulp

What is the marginal zone made up of?

Macrophages and B cells

Where are WBCs compartmentalized in the spleen?

White pulp

The periarteriolar lymphoid sheath (PALS) contains:

T cells and B-cell follicles

Where is Mucosa-associated lymphoid tissue (MALT) found?

In the linings of the digestive, respiratory, and urogenital systems, as well as in the skin

What is GALT (Gut-Associated Lymphoid Tissue)?

A version of MALT only found in the digestive system