Exam 2 - Chapter 15 Flashcards
Humoral Immunity
Eliminates microbes from blood and tissue fluids. Involve B cells
Cell-Mediated Immunity
Eliminates microbes from within a host cell, usually viruses or bacteria, and sometimes cancerous cells. Involve T cells
Naive Lymphocyte
A lymphocyte that needs a confirmation signal before it can react to an invader
Activated Lymphocyte
A B or T cell that once it knows the invader needs to be killed, it proliferates
Effector Lymphocytes
Short lived cells that express certain traits to kill invaders
Memory Lymphocytes
Long lived cells that recognize a past antigen and reacts quickly
Plasma Cells (Effector B Cells)
Descendants of activated B cells, that make antibodies
B Cell Receptor (BCR)
A version of the antibody the B cell is gonna make, except it’s stuck on its surface
Cytotoxic T Cells
Destroy infected host cells that have viruses
Helper T Cells
Direct and assist in the multiple immunity responses
Regulatory T Cells
Surpress the immune response, so we don’t overreact to stupid things like pollen
Secondary Lyphoid Organs
Sites where lymphocytes gather to contact antigens
Peyer’s Patches
Samples intestinal contents via M cells and dendritic cells
Mucosa-Associated Lymphoid Tissue (MALT)
Mucosal immunity prevents microbial invasion via mucous membranes
Skin-Associated Lymphoid Tissue (SALT)
Lymphoid tissues under skin
Primary Lymphoid Organs
Bone and Thymus. Where B and T cells mature. Once any lymphocytes are mature, they migrate to secondary lymphoid organs and wait for any antigens that might invade
Immunogen
An antigen that elicits an immune respone
Immunoglobulin (Ig) Classes
IgM, IgG, IgA, IgD, IgE
IgM
5–13% of circulating antibodies
First class produced during primary response
Principal class produced in response to some T-independent antigens
Pentamer
Five monomeric subunits give 10 antigen-binding sites
Aggregates very effectively
Large size prevents crossing from bloodstream to tissues
Primary role in bloodstream infections
Most efficient class in triggering classical pathway of complement system
IgG
80–85% of total serum immunoglobulin
Also exits bloodstream to enter tissues
Provides longest-term protection: half-life is 21 days
Generally first and most abundant circulating class produced during secondary response
Protect via neutralization, aggregation, opsonization, complement activation, and antibody-dependent cellular cytotoxicity
Transported across placenta to fetus’s bloodstream
Women cautioned to avoid pathogens to which they lack immunity (e.g., Toxoplasma gondii in raw meat, cat feces)
Maternal IgG protects fetus and newborn
Degrade gradually over 6 month period
Infant begins producing
IgG found in colostrum (first breast milk); absorbed by newborn’s intestinal tract
IgA
Monomeric form is 10–13% of serum antibodies
Most IgA is a dimer: secretory IgA (sIgA)
IgA is most abundant immunoglobulin class produced
Secreted form important in mucosal immunity
Gastrointestinal, genitourinary, and respiratory tracts
Xecretions including saliva, tears, breast milk
Protects breast-fed infants against intestinal pathogens
Protection primarily via neutralizing toxins, viruses and interfering with attachment of microbes to host cells
Produce by plasma cells of mucosa-associated lymphoid tissue (MALT); secretory component (polypeptide) added to attach antibody to mucus
IgD
Less than 1% of serum immunoglobulins
Involved with development and maturation of antibody response
Function in serum not clearly defined
IgE
Barely detectable in normal blood
Tightly bound via Fc region to basophils and mast cells
Allows these cells to detect, respond to antigens
Antigen binds to two adjacent IgE molecules carried by mast cell, cell releases histamine and other inflammatory mediators
Basophils and mast cells also release chemicals when IgE binds to normally harmless foods, dusts, pollens, yielding allergic reactions of coughing, sneezing, swelling
Some allergic (hypersensitivity) reactions can be life-threatening
