Innate & Adaptive Immune Systems

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

Microbes must overcome physical barriers (skin, mucous membranes), washing actions (tears, saliva), temperature (fever), and chemical defenses (lysozyme, gastric pH).

What are defensins?

Defensins are antimicrobial peptides produced by epithelial cells that damage microbial membranes, found in mucus and sebum.

What are lysozymes?

Lysozymes break bonds between sugars (NAM & NAG) in the peptidoglycan layer and are 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 and enhances innate function.

What are the different types of WBCs?

Neutrophils, basophils, eosinophils, lymphocytes, and monocytes.

What is phagocytosis?

Phagocytosis is the process of cell-eating where host innate cells eat pathogens and break them down, performed by neutrophils, monocytes, macrophages, and dendritic cells.

How do innate immune cells recognize a pathogen?

Innate immune cells recognize pathogens via pathogen-associated molecular patterns (PAMPs).

What are cytokines?

Cytokines are small proteins used to communicate between different immune cells, signaling to bring more cells.

What is inflammation?

Inflammation is characterized by redness, swelling, and heat due to trauma, helping to contain infection, recruit immune cells, mobilize immune response, and repair tissue.

How does clotting help prevent infection?

Clotting restricts additional pathogen access.

Does a wound result in vascular permeability increasing or decreasing? Why?

A wound results in increased vascular permeability to allow immune cells to pass from the blood into surrounding tissues.

How does the innate and adaptive immune system communicate?

Antigen-presenting cells (APCs) like macrophages and dendritic cells communicate with adaptive immune cells (helper T cells) by presenting antigens via the MHC2 complex.

What are APCs?

APCs, or antigen-presenting cells, are macrophages and dendritic cells that break down pathogens via phagocytosis and present the antigen.

What is an antigen?

An antigen is a foreign substance (usually a protein) that induces an adaptive immune response.

Is the Helper T Cell an innate or adaptive immune cell?

The Helper T Cell is an adaptive immune cell that recognizes and learns the shape of antigens, produces more Helper T cells, releases cytokines, and shows B and T cytotoxic cells the antigen.

What do B cells make?

B cells make antibodies for specific antigens, which neutralize bacteria and prevent their entry.

What type of pathogen does the humoral immune response target?

The humoral immune response targets bacteria in the blood.

What is the difference between IgM and IgG?

IgM is the first antibody class produced during infection (short-term protection), while IgG is the most prevalent in circulation and produced 7-14 days after antigen exposure.

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

The primary response is the production of antibodies after the first contact with antigens, while the secondary response involves rapid elevation of antibodies upon a second exposure due to memory cell response.

What are cytotoxic T cells?

Cytotoxic T cells are immune cells that recognize antigens on host cells and kill them, stimulated by cytokines from Helper T cells.

Explain how humoral and cell-mediated immunity contribute to immune 'memory'.

T cells and B cells transform into memory B cells and memory T cells to recognize previously encountered pathogens.