Immunity Flashcards
What are the two subcategories of the immune system?
Innate (natural) immunity:
First line of defense
Activated when a pathogen is first encountered
Initial response: Sneezing, tearing, coughing, sweating
Adaptive (acquired) immunity:
Becomes prominent as it develops antigen-specific antibodies in response to activation by the innate system
What is the key characteristic of the immune system?
The ability to distinguish between self and nonself
What is the Humoral response mediated by?
B lymphocyte antibodies circulating in the lymph or blood
Cell Mediated Response
Produced by phagocytes, T lymphocytes, and cytokines
Directed primarily at microbes that survive in host cells
Plays a major role in transplanted organ rejection
Does the innate immune response require prior pathogen exposure for activation?
nope!
Response is always the same regardless of prior exposure to the same pathogen
What is the most numerous of all the white blood cells?
Neutrophils
Responsible for elevated WBCs that occur with infection
Half-life 6 hours
Basophil and Mast Cells:
Express cell surface high affinity receptors for immunoglobulin E (IgE)
Key initiators of immediate hypersensitivity reactions through the release of histamine, leukotrienes, cytokines, and prostaglandins
Stimulate smooth muscle contraction
Play a major role in atopic allergies (hay fever, asthma, eczema)
Respond directly to bacterial pathogens
What acts as messengers in the immune system and modulate the response to pathogenic microbes, tumor cells, and apoptotic cells?
cytokines
What are the most potent antigen-presenting cells (APCs)
Dendritic Cells (DCs)
What “Complements” the innate and adaptive immune systems?
Compliment system
Main function: Mark pathogens for permanent destruction and recruit other immune cells to destroy the pathogens
Key points about the adaptive immune system
Produces antibodies with specificity for different pathogens
Slower response than the innate system but develops immunological memory that allows for a more aggressive response with repeated exposure to a pathogen
Adaptive immune system cells develop from hematopoietic stem cells that differentiate into a common lymphoid progenitor
The common lymphoid progenitor further differentiates into four types of mature lymphocytes:
B lymphocytes (B cells)
T lymphocytes (T cells)
Natural killer cells (NK)
Natural killer T cells (NKT)
What cells produce antibodies?
B Cells
What cells originate in bone marrow, mature and differentiate in the thymus before migrating to secondary lymphoid organs?
T Cells
Some T cells become memory T cells – quicker response with repeat exposure to an antigen
Do Natural Killer Cells (NK) directly attack pathogens?
nope!
What is active immunity?
Active immunity is achieved when a pathogen is administered for the purpose of stimulating the immune system to produce antibodies specific for the antigen
With repeat exposure to the antigen, the adaptive immune system provides a quicker and more efficient response
Vaccines:
Live, attenuated vaccines:
Long lasting protection immunity, but concerns regarding mutation and reversion to the live pathogen that will cause disease
Inactivated bacterial toxins: Used for bacterial diseases that are caused by a toxin produced by the bacterium (not the bacterium itself)
Example: tetanus vaccine
Shorter length of protection than live vaccines and require boosters for long term immunity
What is passive immunity?
Passive Immunity:
Occurs when an individual receives another person’s antibodies to help prevent or fight infectious diseases
Protection is immediate but short-lived (lasting only a few weeks or months)
Vaccine type
