Immunology 1 Flashcards
What are the primary roles of the immune system?
Protection from pathogens and parasites
What oral manifestations can arise from bacterial infections?
- Congenital syphilis
- Hutchinson’s incisors
- Periodontal disease (bacterial biofilm)
What oral manifestations are associated with viral infections?
- Primary herpetic gingivostomatitis
- Kaposi’s sarcoma – uncontrolled HIV
What oral condition is caused by fungi?
Oral thrush/candidiasis
What are some examples of parasitic infections that can affect the oral cavity?
- Helminths
- Entamoeba gingivalis (protozoa)
What constitutes the first line of defense against pathogens?
Physical and chemical barriers such as epithelial layers
List some strong external barriers to infection.
- Nails
- Hair
- Skin
- Eyes
Identify some more vulnerable mucosal membranes.
- Respiratory tract
- Urogenital tract
- Gastrointestinal tract
What are tight junctions?
Structures that make it difficult for pathogens to squeeze between and gain entry
What role do cilia play in the immune response?
Sweep bacteria to be swallowed down into the gut
How does mucus contribute to the immune defense?
Prevents bacteria from adhering to mucous membranes and is swept by cilia
What are the dual roles of saliva in immune protection?
- Mechanical protection
- Chemical protection
What is the significance of low pH in the gut?
Kills microbes
What are antimicrobial peptides and their role?
Cause damage to bacterial cell membranes, leading to cell death
Define zymogen.
Inactive form of an enzyme that needs proteolytic cleavage to become active
What are the three main classes of antimicrobial peptides?
- Defensins
- Cathelicidins
- Histatins
What distinguishes Gram-positive bacteria from Gram-negative in terms of lysozyme susceptibility?
Gram-positive species are more susceptible due to lack of an additional lipid envelope
What are the two arms of the immune system?
- Innate arm
- Adaptive arm
How quickly does the innate immune system respond?
Minutes to hours
What are the characteristics of the adaptive immune response?
Days to weeks, needs activation, provides lasting protection
What is the role of the innate immune system in pathogen control?
Limits pathogen proliferation and spread
What type of immune response does the adaptive system provide?
More potent activity against virulent pathogens
What is immunological memory?
Gives a more efficient response to previously seen pathogens
What happens during the lag phase of an immune response?
Period between first exposure to an antigen and detectable immune response
How does the innate immune system respond to reinfections?
In the same way, without changing its response
What is the complement system?
A group of 30+ plasma proteins involved in immune response
What are the three pathways to activate the complement system?
- Classical pathway
- Alternative pathway
- Lectin pathway
What is the function of opsonization?
Increases efficiency of phagocytosis by attaching to microbes
What is the membrane attack complex (MAC)?
A complex that penetrates bacterial membranes, leading to cell lysis
What triggers the classical pathway of complement activation?
C1 binding to pathogen or antibodies
What is the outcome of C3b deposition on microbes?
Triggers a response as microbes cannot remove C3b
What is the role of mannose-binding lectin in the lectin pathway?
Binds to mannose on microbe surfaces, activating complement
