DBMB 712: Immunology Week 2

What does an elevated WBC count mean?

infection

What does high C-reactive protein in the blood mean?

complement system is activated

Which is a rapid response: innate or adaptive?

innate

Which is a delayed response: innate or adaptive?

adaptive

True/False. The innate immune system has memory.

False

Is innate specific or non-specific?

non-specific

What is the cytokine-mediated fever mechanism?

1. Pathogen

2. Cytokines (IL-1, IL-6, TNF-alpha)

3. Hypothalamus

4. PGE2

5. Fever

What is the lymph node activation pathway?

1. Antigen-presenting cell

2. T-helper cell

3. B-cell activation

4. Dendritic cells migrate to nodes

5. T helper cells stimulate B cells -> antibody production

What does node swelling mean?

immune cell proliferation

What does IL-6 lead to?

fever and acute-phase proteins being activated

What is the link between innate and adaptive immunity?

It is sequential: innate -> adaptive

It is cooperative (they work together)

What makes mealses special with immunity?

It wipes out all the memory cells for every virus the pt has been exposed to before

What are the natural defense mechanisms of the oral cavity?

1. Oral mucosa

2. Nasopharynx-associated lymphoid tissues (tonsils)

3. Tongue

4. Saliva and salivary glands

5. Tooth plaque fluid and adjacent GCF

What are the two major mechanisms of innate immunity in the oral cavity?

1. Immune exclusion (inactivation, clearance of microbes from oral mucosa+enamel)

2. Inflammation (occurs when we need to remove infectious agent after mucosal penetration)

What is the difference between immune exclusion and inflammation?

- Immune exclusion is the inactivation and clearance of microbes from the oral mucosa/enamel BEFORE any mucosal penetration

-Inflammation is the next step that occurs when we need to remove the infectious agent AFTER mucosal penetration.

For the innate immunity in the oral cavity, what are ways that we use inflammation to remove the infectious agent?

1. Phagocytosis

2. Recognition of PAMPS by PRR

3. Inflammatory mediators

What do epithelial desolation, saliva flow, and mucin/agglutinins function for?

physical removal or microbes

What is the function of lysozyme?

causes cell lysis

What is lactoferrin's/ apolactoferrin function?

iron sequestration

What does the complement system function for?

activates neutrophils

What is secretory IgA's function?

prevents microbial adhesion and metabolism

What are IgG, IgA, and IgM's functions?

prevent microbial adhesion; opinions; complement activators

What parts of the oral mucosal epithelium help prevent penetration of microbes into deeper tissues?

- saliva

- keratin

- granular layer

- basement layer

What do cells in the oral mucosa express ______ for immune surveillance?

PRRs

What can some pathogens do to avoid being detected by the immune system?

- Some periodontal pathogens hide within buccal epithelial cells as a protective niche

What are some antigen-nonspecific denfense chemicals in oral secretions?

1. Calprotectin

2. Antimicrobial actions of saliva

3. Defensins

4. Gingival crevicular fluid

How can antigen-nonspecific defense chemicals in oral secretions help for an immune response?

- they can aggregate or agglutinate microbes

- they can promote or inhibit microbial adhesion

- they can directly kill or inhibit the growth of microbes

- they can contribute to microbial nutrition

How does calprotectin work?

- it is produced by nonkeratinized oral epithelial cells

- deprives microbes of essential divalent ions

- present in neutrophils, monocytes, macrophages

How does saliva act as an antigen-nonspecific defense?

- The flow of saliva and swallowing removes debris and unattached microbes

- It replenishes fluids in the oral cavity, which dilutes/clears microbes and acid from plaque

- Contains neurophils and antigen-nonspecific defense chemicals (secretory IgA, IgA, IgG) and other enzymes

How does defenses act as an antigen-nonspecific defense?

- it forms pores that cause osmotic instability and cell lysis

- It can be found in saliva

- it is active aganist fungi

- causes degranulation of mast cells

- chemotactic for neutrophils, dendritic cells, memory T cells

How does GCF act as an antigen-nonspecific defense?

- contains blood components including leukocytes are in the junctional epithelium

-

Normally, the flow of GCF is high or low?

low

What causes an increase of flow of GCF?

increases with inflammation to flush oral surfaces that are vulnerable to penetration by microbes

When does the composition of GCF change?

changes during inflammation increasing in the number of lymphocytes and neurophils

What is immune exclusion/colonization resistance?

bacteria that normally live in our oral cavity complete aganist pathogenic bacteria

What is an example of when a potential pathogens proliferate?

infection by the fungal pathogen Candida albicans after most of the commensal bacteria are killed by broad-spectrum antibiotics such as tetracycline

What is microbial antagonism?

one species harms, and can exclude, the other

What is synergism?

two species cooperate to benefit both

What is symbiosis?

one species benefit, other may be unaffected or harmed

What is commensalism?

one species benefit, the other is unaffected

What is mutualism?

both species benefit

What is parasitism?

one species benefits, the other is harmed

Where is MALT located and what is it responsible for?

MALT lies beneath the oral mucosal epithelium and contains phagocytes and APCs, which sample antigens in the oral mucosa and provide the link between innate and acquired immune response

What drives adaptive immunity?

MALT

What is found around the basement membrane to help eliminate pathogens that overcome innate immune exclusion and pass through the intact oral mucosal epithelium?

lymphoid cells

What are the extraoral lymph nodes and intraoral lymphoid tissues present in the mouth?

- palatine and lingual tonsils

- salivary gland lymphoid tissue

- gingival lymphoid tissue submucosal lympoid cells scattered in the submucosa

What and where does the lymph tissues drain from the oral cavity?

- network of lymph capillaries and lymph vessels links the oral mucosa, gingivae, and pulp to other structures, such as the tongue, and drain into the submandibular, retropharyngeal, and other lymph nodes

What are the two ways microbes can enter the lymphatic system?

1. Microbes have to overcome the innate immune system and penetrate through the oral mucosa

2. Transported to the lymphatics by phagocytes

When is an immune response elicited?

When the microbial antigens reach the lymphocytes in the MALT

What happens after the lymphocytes that have encountered an antigen is activated?

The lymphocytes leave the MALT via the efferent lymphatics and enter the circulation, after which they relocate to the lamina propria to drive the acquired immune response

What are the types of T cells in the lamina propria?

CD4 and CD8 but some intraepithelial lymphocytes (IELs

What is the most predominant T cells in the lamina propria?

CD4 and CD8 types

What are the B cells in the lamina propria associated with?

acini of the major and minor salivary glands and they synthesize IgA

What are some clinical connections to look out for in the oral cavity defense?

Reduced saliva -> xerostomia -> candidasis (easier for things to grow well in a dry environment

Neutrophil defects -> aggressive periodontitis

IgA deficiency -> recurrent infections