Section 1: Overview of Host Defenses

What is immunology?

• study of host defenses

—> defending against foreign matter

• the response of an organism to antigenic challenge and recognition of self vs. non-self.

What are examples of foreign matter the immune system attacks?

• Bacteria

• viruses

• viroids

• satellites

• prions

• malignant cells

• transplants

• transfused fluid

What are the two types of immunity?

• Innate (natural/nonspecific) immunity

• acquired (adaptive/specific) immunity

Describe innate immunity.

• Nonspecific defenses that activate immediately upon exposure

• same response with each encounter

Describe acquired immunity.

Specific defenses that develop to specific foreign material; involves cell memory; quicker & stronger with each encounter.

What three responsibilities does a healthy immune system have?

Surveillance of the body, recognition of foreign material (distinguishing self from non-self), destruction of foreign/non-self.

What is autoimmunity?

When the body cannot distinguish self from non-self, leading to damage (e.g., rheumatoid arthritis).

What are self markers on human cells called?

Major Histocompatibility Complex (MHC) molecules.

What are non-self markers?

Pathogen Associated Molecular Patterns (PAMPs) or Microbe Associated Molecular Patterns (MAMPs).

What do Pattern Recognition Receptors (PRRs) do?

Bind to PAMPs/MAMPs on host cells to determine if an immune response is needed and to what extent.