BIOL438: Microbiology for Optometry Review

This set of flashcards covers key concepts, definitions, and regulatory mechanisms relevant to Microbiology for Optometry, focusing on innate immunity and the role of various cytokines and immune responses.

What are antigens?

Molecules recognized as non-self by the immune system.

What determines antigenicity?

The foreignness, size, composition, and degradability of the antigen.

What are haptens?

Small antigens that require a carrier to be immunogenic.

List the types of bacterial antigens.

O-Antigen, M-Antigen, H-Antigen, K-Antigen.

What are the two different systems of host defenses?

Innate defenses and acquired defenses.

Define innate defenses.

Constitutive defenses that are always active and do not improve with exposure.

What are the four types of innate defenses?

Physical, chemical, phagocytic, and inflammatory defenses.

What constitutes the structure of the skin?

A surface area of ~2 m2 with dead cells and secretions.

What is the surface area of ciliated epithelium?

~400 m2.

List some defense behaviors of the body.

Salivary flow, swallowing, tears, peristalsis, coughing, and sneezing.

What do noxious chemicals do?

They kill or inhibit microbes.

What substances serve as noxious molecules in the body?

Hydrochloric acid, bile acids, fatty acids, sodium chloride, and mucous.

Give examples of enzymes that act as chemical defenses.

Lysozyme, DNase, RNase, and proteases.

What is the function of metal chelators in the body?

They limit the availability of essential metals like iron.

What are defensins?

Short peptide antibiotics in serum that form pores in bacteria.

What is the complement cascade?

A special chemical defense protease cascade found in serum that tags, attracts, and kills pathogens.

What do innate immune cells recognize pathogens with?

Receptors that recognize pathogen-associated molecular patterns (PAMPs).

What characterizes PAMPs?

Molecules characteristic of a broad range of microbes, not normally present in the body.

What are examples of pattern recognition receptors (PRRs)?

Toll-like receptors (TLRs), lectin receptors, scavenger receptors, and cytosolic innate receptors.

What is the role of Toll-like receptors (TLRs)?

Recognize a variety of PAMPs on microbial surfaces.

What do lectin receptors recognize?

Carbohydrates common to pathogen cell surfaces.

What do scavenger receptors bind?

Negatively charged ligands like sulfated sugars and lipopolysaccharide.

What activates cytosolic innate receptors?

Intracellular PAMPs such as viral nucleic acids and bacterial signaling molecules.

What is the role of opsonin receptors?

Trigger phagocytosis when they bind complement proteins or immunoglobulins on microbial surfaces.

What are the causes of inflammation?

Increased blood flow, erythema, increased vascular permeability, and influx of phagocytes.

What is the function of phagocytes?

Identify, ingest, and destroy microbes.

What distinguishes neutrophils among phagocytes?

They are short-lived and mediate the earliest phase of the inflammatory response.

Describe the phagocytosis process.

Bacterium attaches to pseudopodia, ingested forming a phagosome, which fuses with lysosome for digestion.

What complex is involved in IL-1 activation?

Inflammasome, consisting of NOD-like receptors and ASC.

What do NK cells do?

Kill infected cells and tumor cells through mechanisms like perforin/granzyme.

What are cytokines?

Soluble proteins secreted by cells of innate and adaptive immunity that regulate immune responses.

What are the main sources of cytokines?

Mononuclear phagocytes and lymphocytes.

How do cytokines initiate actions?

By binding to specific membrane receptors on target cells.

What types of actions can cytokines have?

Local and systemic actions, including autocrine, paracrine, and endocrine.

What does pleiotropy in cytokines mean?

One cytokine can have multiple effects depending on the target cell.

Define redundancy in cytokine actions.

Multiple cytokines can produce the same effect on target cells.

What is synergy in the context of cytokines?

When two or more cytokines work together for a greater effect.

What is antagonism in cytokines?

When one cytokine interferes with the action of another.

What are some mediators of innate immunity?

TNF, IL-1, IL-6, IL-12, Type I IFNs, IL-15, IL-18.

Which cytokines are regulators of adaptive immunity?

IL-2, IL-4, IL-5, IFN-g, TGF-b.

What factors stimulate hematopoiesis?

Granulocyte-CSF, G-CSF, macrophage-CSF, erythropoietin.

What are the two types of cytokine receptors?

Type I and Type II cytokine receptors.

What do Toll-like receptors sense?

The presence of bacterial patterns in the body.

What happens when cytokines bind to their receptors?

Distinct signal transduction pathways are activated, leading to gene activation.

Describe the role of TNF in varying concentrations.

Low: local inflammation; Moderate: systemic effects; High: septic shock.

Which cytokines mediate and regulate innate immunity?

TNF, IL-1, IL-6, Type I IFNs, IL-12.

How do macrophages respond to inflammatory stimuli?

They produce pro-inflammatory cytokines such as TNF and IL-1.

What are the effects of IL-1 and TNF on endothelial cells?

Make them leaky and sticky for leukocyte adhesion.

Identify the main cellular source of pro-inflammatory cytokines.

Mononuclear phagocytes.

What induces the production of eicosanoids?

Arachidonic acid from membrane phospholipids.

Which fatty acids are considered omega-3?

Linolenic acid.

Define leukotrienes.

Mediators produced by lipoxygenase involved in inflammation and asthma.

What is the significance of COX-1 and COX-2?

COX-1 is constitutive and involved in homeostasis, while COX-2 is induced during inflammation.

Describe COX-1.

Expressed in most tissues, involved in maintaining mucous production.

List the primary effects of prostaglandins in the body.

Activation of inflammatory responses, pain, and fever.

What role do thromboxanes play?

Stimulate constriction and clotting of platelets.

What is the role of PGE2 in labor?

It induces uterine contractions.

What are some adverse effects of non-steroidal anti-inflammatory drugs (NSAIDs)?

Gastrointestinal irritation, ulcers, excessive bleeding.

What does aspirin inhibit?

Both COX-1 and COX-2, blocking arachidonic acid entry into the active site.

What potential effect does Tylenol have?

Inhibits activity of COX-3 but evidence remains inconclusive.

What is the impact of low-dose aspirin therapy?

Reduces blood clotting ability, lowering heart attack and stroke risks.

What advantage do COX-2 inhibitors offer?

They are less likely to cause gastrointestinal side effects.

What was the primary reason behind the withdrawal of Vioxx?

Increased risk of heart attacks and strokes.

What does rational drug design involve?

Base compound development on structural studies and cellular mechanisms.

What do chemokines do during inflammation?

Direct leukocyte migration to sites of infection.

What family classification of chemokines exists?

CXC, CC, C, and CX3C based on cystein residue arrangement.

What are lipoxins?

Anti-inflammatory products of lipoxygenase interactions.

What role does PGH2 play?

It is the precursor in prostaglandin synthesis.

What are the functional implications of prostaglandins?

They activate inflammation, regulate pain and fever, and assist in healing.

What secondary effects can prostaglandins have on the GI tract?

Increase mucus secretion and inhibit acid synthesis.

What triggers the formation of eicosanoids?

Degradation of phospholipids in cell membranes.

What area of the immune response do cytokines have a significant impact on?

Cytokines regulate both innate and adaptive immune responses.

How does the immune system recognize pathogens?

Through PRRs detecting characteristic PAMPs.

What is the function of IL-2 in immune responses?

Stimulate proliferation and differentiation of T and B cells.

What is the consequence of high TNF levels?

Potentially lead to septic shock and systemic inflammation.

How do eicosanoids exert their effects?

By acting as local mediators in inflammation and immune responses.

What kind of immune cell is primarily responsive to cytokines?

Monocytes and macrophages.

What does systemic action of cytokines refer to?

Cytokines acting at distant sites through the blood circulation.

What pattern do pattern recognition receptors follow?

Recognizing molecular patterns that are distinct to pathogens.

What type of immunity do monokines and lymphokines involve?

Both are types of cytokines involved in immune responses.

What receptors are significant for macrophage activation?

CD40 and CD40L.

What is the potential risk of COX-2 selective inhibitors?

They may increase cardiovascular risks.

What is the role of eicosanoids during inflammation?

To modulate pain and the inflammatory response.

What is the significance of the COX pathway?

It relates to the production of inflammatory mediators.

What are the therapeutic effects of NSAIDs?

Pain relief and reduction of inflammation.

What do cytokine receptors typically consist of?

Unique ligand-binding chains and signal-transducing chains.

In what scenarios are chemokines produced?

During inflammation and in response to microbial infection.

What are the local effects of IL-1 and TNF on blood vessels?

They induce increased permeability and adhesion of leukocytes.

What do anti-inflammatory cytokines achieve?

They inhibit excessive inflammation and promote resolution.

What triggers the production of IL-1 and TNF?

Recognition of PAMPs through PRRs.

What are the consequences of aspirin’s inhibition of COX?

Reduces pain and inflammation but increases bleeding risk.

Explain the role of macrophage colony-stimulating factor (M-CSF).

Stimulates growth and differentiation of macrophages.

What do granulocyte-CSF and GM-CSF do?

Stimulated the production of granulocytes and macrophages.

What immune response utilizes eicosanoids?

The inflammatory response.

What inhibitors are included in the category of NSAIDs?

Aspirin, ibuprofen, and naproxen.

What general impact do cytokines have on the immune response?

They fine-tune the immune response to pathogens.

What potential outcome can result from excessive TNF production?

Systemic inflammatory syndromes and shock.

What are the systemic effects of moderate levels of TNF?

Fever and acute phase response.

What is the role of eicosanoids in asthma?

Promoting bronchoconstriction.

Explain how eicosanoids derived from arachidonic acid can be therapeutically targeted.

By using inhibitors that disrupt their synthesis, like NSAIDs.