I&I week 7 Innate, adaptive, and passive immunity

What are the two main branches of the immune system?

Innate and Adaptive immunity

What is a key characteristic of the innate immune system regarding its response time?

It responds quickly, within minutes to hours

Does the innate immune system have memory?

No, it lacks memory

What is the major innate defense process?

Inflammation

How long does the adaptive immune system take to respond upon first exposure to an antigen?

Approximately 7-10 days or longer

What drives the adaptive immune system?

Antigens

What is a key characteristic of the adaptive immune system regarding specificity?

It is specific and responds to each unique antigen

Does the adaptive immune system generate memory?

Yes, memory is generated after the first exposure to an antigen

What are the main cells of the innate immune system?

Dendritic cells, Macrophages, Neutrophils, and NK cells

What are the main cells of the adaptive immune system?

B-lymphocytes and T-lymphocytes

How does the effectiveness of the innate immune system change over time?

It does not improve over time

How does the effectiveness of the adaptive immune system change with repeated exposure to an antigen?

It improves with repeated exposure

What type of specificity does the innate immune system have?

Broad specificity

What type of specificity does the adaptive immune system have?

Unique (exquisite) specificity

Name two key examples of how innate and adaptive immune systems interact.

Innate cells presenting antigens to T-cells and Antibody acting as an opsonin

Give an example of an innate immune cell that presents antigen to T-helper cells.

Dendritic cells or Macrophages

What is an opsonin?

A molecule that can facilitate phagocytosis

Give two examples of opsonins.

Antibodies and some Complement proteins

What part of the antibody binds to the antigen?

Fab region

What cells express Fc receptors that bind to antibodies?

Phagocytic cells

What is the function of the Fc region of an antibody?

Binds to Fc receptors expressed on cells

Which immune cells are primarily involved in recognizing opsonized pathogens?

Neutrophils

What is passive immunity?

Adaptive immunity developed in one animal that is given to another animal

What is most often transferred in passive immunity?

Antibodies

Give an example of passive immunity.

Antibody in colostrum acquired by a newborn

Provide another example of passive immunity involving antibodies.

Antibody made in one animal and given to another by a healthcare provider, such as Human Rabies Immunoglobulin (HRIG)

What is HRIG?

Human Rabies Immunoglobulin, an example of passive immunity

What is the source of anti-rabies antibody (HRIG)?

Serum harvested from humans vaccinated with rabies vaccine

In rabies post-exposure prophylaxis, when is HRIG given?

To a person bitten by a rabid animal who was never vaccinated against rabies13 ...

If a person has been previously vaccinated against rabies and is exposed, should HRIG be given?

No

What biologics are used as rabies vaccines in humans?

HDCV (Human diploid cell vaccine) and PCEC (Purified chick embryo cell vaccine)

What is CPMA?

Canine Parvovirus Monoclonal Antibody, a therapeutic for parvovirus in dogs

Is CPMA an example of active or passive immunity?

Passive immunity

What is the best way to prevent parvovirus in dogs?

Vaccination

What is the first step in post-exposure prophylaxis for rabies?

Wound cleaning

What are the cells of the adaptive immune system?

B and T lymphocytes

What are the molecules of the adaptive immune system?

Antibodies and cytokines

What is the difference between humoral and cell-mediated immunity?

Humoral immunity involves secreted molecules, while cell-mediated immunity involves cells

Name three examples of innate immune cells

Dendritic cells, macrophages, neutrophils

What is a sentinel cell?

Innate immune cells that detect invaders/tissue damage

Give two examples of sentinel cells.

Dendritic cells and macrophages

What is the function of phagocytic cells?

To engulf and kill invaders

Give two examples of phagocytic cells.

Macrophages and Neutrophils

What is the function of antigen-presenting cells?

To present antigen to T-lymphocytes

Give two examples of antigen-presenting cells.

Dendritic cells and macrophages

What is the function of NK cells?

To kill host infected and tumor cells

What is the humoral component of the adaptive immune system?

Antibodies

What cells produce antibodies?

B-lymphocytes (plasma cells)

What is the function of antibodies?

Target invaders when outside of cells

What are the two types of T-lymphocytes involved in cell-mediated immunity?

T-helper lymphocytes and Cytotoxic T-lymphocytes (CTLs)

What is the function of T-helper lymphocytes?

Make cytokines to help B- and T-cells

What is the function of cytotoxic T-lymphocytes (CTLs)?

Target/kill infected HOST cells and HOST tumor cells

What is the difference between humoral and cellular immunity?

Humoral = secreted molecules, Cells = cells doing their job

How does the innate immune system detect invaders or tissue damage?

Via sentinel cells

What is the role of inflammation in innate immunity?

Results in increased blood flow and accumulation of cells to tissues where needed

What are antigens?

Foreign molecular structures

What recognizes antigens in the adaptive immune system?

B- and T-lymphocytes

What do innate cells express to bind to molecules on microbes?

Pattern Recognition Receptors (PRRs)

What is an example of a molecule recognized by PRRs on macrophages?

LPS (Lipopolysaccharides) on Gram-negative bacteria

How many unique antigen receptors does a B- or T-cell have?

One

What is the role of antibody in acting as an opsonin?

Antibody binds to the microbe, and then a phagocytic cell recognizes the antibody

What part of the antibody binds to the phagocytic cell?

The Fc region

What initiates the adaptive immune response?

Antigen

What is the role of the MHC molecule in antigen presentation?

It is on the surface of the APC (Antigen Presenting Cell)

What is the definition of an effector cell?

A cell that has been activated and can now do something, like kill another cell or make and secrete a protein

What is the role of complement proteins in innate immunity?

Some complement proteins can function as opsonins

What is the role of the complement system in immunity?

Part of the innate immune system involving molecules

What is the significance of changes in the SARS-CoV-2 spike protein?

It results in the generation of antibodies unique to each variant, such as Delta and Omicron

How does the adaptive immune response differ between the Delta and Omicron variants of SARS-CoV-2?

The adaptive humoral immune response generates antibodies unique to the Delta variant spike protein antigen and antibodies unique to the Omicron variant spike protein

What is the purpose of revaccination after exposure to rabies if previously vaccinated?

The source does not have an answer to this question.

Why is HRIG not given if previously vaccinated against rabies?

The source does not have an answer to this question.

What is the typical response time for the adaptive immune system after subsequent exposures to the same antigen?

~1-3 days

What is the role of dendritic cells in the immune response?

Detect/kill microbes, mediate inflammation, and are antigen-presenting cells

What happens to healthy, unvaccinated dogs/cats/ferrets exposed to rabies, according to NASPHV recommendations?

They should be euthanized immediately

f the owner is unwilling to euthanize a rabies-exposed, unvaccinated dog/cat/ferret, what is the alternative?

Strict quarantine for 4 (dogs and cats) or 6 (ferrets) months