CHAPTER 1 Introduction to the Immune System: Nomenclature, General Properties, and Components

Flashcards covering the fundamentals of the immune system, including innate vs. adaptive immunity, cell types, lymphoid organs, and immune response phases.

What is the essential function of the immune system?

To differentiate self from non-self in order to protect the body from both external (e.g., infections, toxic products) and internal (e.g., cancer) challenges.

What is a pathogen?

Any organism with the potential to cause disease.

How are extracellular pathogens typically spread throughout the body?

They are spread by lymphatics and blood.

Which innate immune cells and mediators are used to deal with intracellular infections?

Natural Killer cells and macrophages which release mediators that kill infected cells.

What refers to any marker that can be recognized by the immune system?

Antigen.

What theory states that the immune system constantly monitors the body for the appearance of tumors?

Immune Surveillance Theory.

What is the clinical definition of an allergy?

A foreign substance that is not typically harmful to your body.

How does the innate immune system recognize microbes?

It recognizes structures shared by microbes called pathogen-associated molecular patterns (PAMPS).

What is the primary characteristic of adaptive immunity regarding prior exposure?

Lymphocytes have the capacity to generate immunological memory that allows for faster recognition of previously encountered pathogens.

What is the composition of pus?

Dead neutrophils, bacteria, and skin cells.

Which cells serve as a 'sentinel' in tissue and provide a link between innate and adaptive immune responses?

Dendritic Cells.

What is the function of the Complement system?

A system of plasma and cell surface proteins that interact to generate effectors of innate and adaptive immunity.

In humoral immunity, which cells secrete antibodies to eliminate extracellular microbes?

B lymphocytes (B cells).

What are the two ways active immunity can be acquired?

Naturally acquired through infection or artificially acquired through vaccination.

What is 'immunologic tolerance'?

The ability of the immune system to coexist with (tolerate) potentially antigenic self molecules, cells, and tissues.

What is a 'clone' in the context of lymphocytes?

A population of lymphocytes with identical antigen receptors and therefore specificities, presumably derived from one precursor cell.

What are the five phases of an adaptive immune response?

Recognition, Activation, Effector Function, Decline (homeostasis), and Memory.

How long does a primary immune response usually take to 'build an army'?

2-4 weeks.

Which pluripotent progenitor gives rise to erythrocytes and white blood cells like neutrophils and monocytes?

Myeloid Progenitor.

Which signaling complex is associated with the T-cell receptor (TCR)?

The CD3 complex.

Which MHC molecule is recognized by CD4+ T Helper Lymphocytes?

MHC Class II (MHC CII).

What is the primary role of Regulatory T Lymphocytes (Tr)?

They play a protective role by shutting off the immune response to prevent excessive damage to normal cells and tissues.

Where do T cells undergo maturation after originating in the bone marrow?

The Thymus.

Which chemokine receptor is expressed by B cells to recruit them to follicles?

CXCR5.

What is the function of the Spleen regarding antigens?

It is the site where immune responses are initiated to blood-borne antigens.

What is the function of M-cells in the mucosal immune system?

They sample antigen from the lumen and deliver it to Dendritic Cells in the underlying Peyer’s patch.

What is the role of the Germinal Center in a lymph node?

It is the site of intense B cell proliferation, selection, maturation, and cell death.

What specific antibody isotype is abundantly produced in mucosal tissues to neutralize microbes?

Immunoglobulin A (IgA).

Which receptor do naïve T cells express to home to the paracortex (T cell zone) of a lymph node?

CCR7.

Where do memory B cells typically take up residence?

In the bone marrow and peripheral lymphoid organs.