Innate & Adaptive Immune Systems

Innate Immune System

What are the different types of nonspecific tactics that microbes must overcome?

 -       Physical barriers: impede invasion (skin, mucous membranes, eyelids)

-       Washing actions: prevent pathogen attachment (tears, saliva, urination)

-       Temperature: inhibits microbial growth (fever)

-       Chemical defense: (lysozyme, gastric pH)

 

What are defensins?

  • AMP produced by epithelial cells that damage microbial membranes

  • Found in mucus and sebum

 

What are lysozymes?

  • Breaks bonds between sugars (NAM & NAG) in the peptidoglycan layer

  • Found in tears, mucus, and saliva

Why does the body temperature increase in response to an infection?

  • Increasing body temperature inhibits microbial growth because microbes can’t survive the heat.

  • Increases innate function

What are the different types of WBCs?

  • Neutrophils

  • Basophils

  • Eosinophils

  • Lymphocytes

  • Monocytes

 What is phagocytosis? What type of cells perform phagocytosis?

  • Cell-eating (host innate cells eat pathogen & break it down)

  • Neutrophils, monocytes, macrophages, dendritic cells

 

·       How do innate immune cells recognize a pathogen?

  • Phagocytic leukocytes recognize pathogen-associated molecular patterns (PAMPs)

·       What are cytokines?

  • Small proteins that are used to communicate between different immune cells. They signal to bring more cells

     

·     What is inflammation?

  • Redness, swelling, and heat that our body generates due to some sort of trauma.

  • A mechanism that helps contain the infection, recruits innate immune cells, mobilizes immune cells, and repairs tissue damage. Increased blood flow

 ·      How does clotting help prevent infection?

  • It restricts additional pathogen access.

·      Does a wound (like a cut on your arm) result in vascular permeability increasing or decreasing? Why?

  • By increased vascular permeability, immune cells pass from the blood system into surrounding tissues

 

Adaptive Immune System

·      How does the innate and adaptive immune system communicate?

  • Antigen-presenting Cells (Macrophages & Dendritic Cells) communicate to adaptive immune cells (helper T cells) that present the antigen via MHC2 complex

·      What are APCs? What type of immune cells are APCs?

  • Macrophages & dendritic cells are innate immune cells

  • break down pathogen via phagocytosis & presents the antigen

 

·      What is an antigen?

  • Foreign substance (usually a protein) that induces an adaptive immune response

 

·      Is the Helper T Cell an innate or adaptive immune cell? What is the role of the Helper T cell?

  • type of WBC & Adaptive immune cell

  • recognize  learn the shape of antigens; makes lots of copies of Helper T cells with antigen knowledge; release cytokines; shows b and T cytotoxic cells the antigen

·      What do B cells make and what is the role of these molecules in fighting infection?

  • Make antibodies for specific antigens, which stop bacteria from entering by neutralizing them.

·      What type of pathogen does the humoral immune response target? Where are these reactions occurring?

  • They target bacteria in the blood

·      What is the difference between IgM and IgG?

  • IgM is the first antibody class produced during infection (short-term protection)

  • IgG is most prevalent in circulation and is produced 7-14 days after antigen exposure.

 

How does the humoral immune system respond differently during a primary and secondary response?

  • Primary response is the production of antibodies in response to the first contact with antigens. The secondary response is the rapid elevation of antibodies following a second exposure to antigens due to memory cell response. 

·      What are cytotoxic T cells? What is their target?

  • Cytotoxic T cells are stimulated by cytokines of Helper T cells. They recognize antigens on the host cell and kill it (intracellular).

Explain how humoral and cell-mediated immunity contribute to immune “memory”

  • T cells and B cells turn into memory B cells and memory T cells to recognize pathogens if they resurface.