What are exotoxins?
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Toxins produced by bacteria that cause damage.
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What are exotoxins?
Toxins produced by bacteria that cause damage.
What leads to the occurrence of disease in bacterial infections?
Disease occurs if the bacteria or immune reactions cause sufficient harm to the person.
What do bacteria attach to in the body?
Host cells, usually epithelial cells.
What are Pathogenicity Islands?
Large groups of genes associated with pathogenicity.
What role does adherence play in the infection process?
It is the initial step in the infection process after bacteria enter the body.
What is one route of entry for pathogenic bacteria into the body?
Ingestion.
What is antigenic mimicry in bacteria?
Bacterial antigens mimic the antigens found on host tissues.
What are bacterial virulence factors?
Characteristics that enable bacteria to cause disease.
What is the role of colonization in bacterial virulence?
It allows bacteria to establish themselves in the host environment.
What does it mean when bacterial infections are described as asymptomatic?
It means that many bacterial infections do not show symptoms.
What is one natural defense mechanism found in the upper respiratory tract?
Mucus and ciliated epithelium.
What are plasmids?
Extrachromosomal pieces of DNA capable of replicating.
What is the first step in the pathogenesis of bacterial infection?
Initiation of the infectious process.
What are endotoxins?
Components of the outer membrane of Gram-negative bacteria that can induce immune responses.
What is a key bacterial virulence factor that aids in colonization?
Adherence.
What is the first step in bacterial virulence factors?
Colonization.
What is the definition of invasion in microbiology?
The process whereby microorganisms enter host cells or tissues and spread in the body.
What is an infection?
Multiplication of an infectious agent within the body, even if the person is asymptomatic.
What defines an infectious disease?
Clinically evident illness resulting from infection, characterized by medical signs and/or symptoms.
On what types of surfaces does biofilm commonly facilitate bacterial colonization?
On surgical appliances like artificial valves and catheters.
How does bacteremia facilitate bacterial infection?
It allows bacteria to reach tissues for multiplication.
What are bacterial virulence factors?
Traits that enable bacteria to colonize, evade the immune response, and damage the host.
What is a key aspect of the infectious process related to bacteremia?
The ability of bacteria to disseminate throughout the body.
What is a bacterial virulence factor that helps escape innate immunity?
Capsule.
What structure do bacteria use to attach to host cells?
Pilus.
Which route of entry involves bites from insects?
Arthropod bite.
What is one portal of entry for pathogenic bacteria?
Respiratory tract (upper and lower airways).
What is the role of pili in bacterial virulence?
They enable attachment to host receptors.
What is adherence in the context of bacterial infection?
The process by which bacteria stick to the surfaces of host cells.
What is the role of biofilm in bacterial colonization?
Facilitates colonization of bacteria, especially on surgical appliances.
How do Gram-negative bacteria release their toxins?
Through one of the secretion systems.
What is one function of pore-forming toxins?
Releasing nutrients and causing death of host cells.
What controls toxin synthesis in bacteria?
It can be controlled by chromosome or plasmid.
How does the capsule inhibit the formation of C3 convertase?
By preventing the activation of the complement system.
What is natural transformation in bacteria?
A process where bacteria take up free DNA from their environment.
What type of toxins are classified as Type I (pyrogenic)?
Superantigens.
What effect do pore-forming toxins have on vacuole membranes?
They damage vacuole membranes, allowing bacteria to escape into the cytoplasm.
What is the role of IL-2 in the immune response?
It stimulates the activation and proliferation of T cells.
What happens to bacteria after internalization during invasion?
They can either persist in an intracellular vacuole or escape to the cytosol.
What is the significance of opsonization in the immune response?
It enhances the phagocytosis of pathogens by marking them for destruction.
What happens after bacteria establish a primary site of infection?
They multiply and spread.
What is bacteremia?
The presence of bacteria in the bloodstream.
What defines an opportunistic pathogen?
A microorganism that can cause disease only when the host’s immune system is impaired.
What is a biofilm in the context of bacterial virulence?
An aggregate of interactive bacteria attached to a solid surface or to each other and encased in an exopolysaccharide matrix.
What do mechanisms in bacterial pathogenesis lead to?
The development of signs and symptoms of disease.
What is the role of O-specific polysaccharide in endotoxins?
It induces specific immunity (O-antigen).
What happens to pili once bacteria adhere to the host cell?
Pili depolymerize, enabling bacteria to attach more securely.
How does the capsule contribute to bacterial virulence?
By helping bacteria evade the complement system.
What are bacteriophages?
Viruses that transfer DNA from phage to the bacterium.
What is the function of the 'A' subunit in A-B toxins?
'A' subunit is the active site that exhibits various effects.
What is the effect of IgM and IgA on bacteria?
They cause bacteria to aggregate and facilitate their phagocytosis.
What is the role of the 'B' subunit in A-B toxins?
'B' subunit serves as the binding site.
What are two other portals of entry for pathogenic bacteria?
Genital and urinary tracts.
What is a key bacterial virulence factor related to colonization?
Adherence through a polysaccharide capsule (glycocalyx).
Where is most of the iron located in the host?
Intracellularly, in hemoglobin and myoglobin.
What is the concentration of free iron in its ferric form (Fe 3+) in the host?
Very low due to transferrin and lactoferrin.
What structure is important for bacterial adherence?
Capsule.
Which faculty is Emrah Ruh associated with at Near East University?
Faculty of Medicine.
Which route of entry involves breathing in pathogens?
Inhalation.
What is the process by which bacteria enter the host cell?
Invasion.
What is a pathogen?
A microorganism capable of causing disease.
What route of entry can occur due to physical injury?
Trauma.
What are transposons?
Highly mobile segments of DNA.
Which immunoglobulins bind to bacteria and inhibit their attachment to host cells?
IgG, IgM, and IgA.
What follows colonization in the process of bacterial virulence?
Invasion.
What is the first step in bacterial virulence factors?
Colonization.
What are endotoxins?
Components of the outer membrane of Gram-negative bacteria that can trigger strong immune responses.
What effect do Type II exotoxins have on membranes?
They have a detergent-like effect.
Where can biofilms occur?
Throughout nature, on solid surfaces or among each other.
How does ciliated epithelium contribute to defense in the respiratory tract?
It helps move mucus and trapped particles out of the airways.
What are bacterial virulence factors?
Traits that enable bacteria to colonize, escape the host immune response, and cause damage.
What role do cytokines play in bacterial infections?
They are secreted by macrophages and can activate the complement system.
How do endotoxins contribute to bacterial virulence?
By producing damage to the host.
Why is iron considered essential for bacteria?
It is crucial for a variety of metabolic functions due to its wide oxidation-reduction potential.
What proteins do several bacteria coat their surfaces with?
Host proteins such as fibronectin, lactoferrin, and transferrin.
How do bacteria evade opsonization?
By binding to the Fc region of antibodies, preventing opsonization despite being coated with antibodies.
What is another method by which bacteria can invade host cells?
By directly entering the host cells.
What are some symptoms caused by IL-2?
Fever, vomiting, diarrhea, malaise.
What is common about the core polysaccharide in Gram-negative bacteria?
It is the same in all Gram-negative bacteria.
What does producing damage in the host entail?
It involves causing harm to host tissues and disrupting normal physiological functions.
What is the first step in bacterial colonization?
Adherence to host cells.
Which tract is primarily associated with the gastrointestinal entry of pathogenic bacteria?
Mouth.
What protective layer can enhance bacterial virulence?
Capsule.
What process allows bacteria to penetrate host tissues?
Invasion.
How do superantigens differ from normal antigens in their interaction with MHC II?
Superantigens directly bind to MHC II, bypassing the normal antigen presentation process.
What happens to 'Part A' after entering the host cell?
'Part A' transfers into the cytoplasm.
Which part of the Type III exotoxin enters the cytoplasm?
Only 'Part A'.
What is an endotoxin?
A toxin that is part of the bacterial cell wall and is released upon cell lysis.
What is MAC in the context of bacterial virulence?
Membrane Attack Complex, which bacteria can inhibit.
What is a bacterial virulence factor that helps escape from innate immunity?
Capsule.
How do some bacteria escape from adaptive immunity?
Through antigenic shift and antigenic mimicry.
What are some clinical findings associated with LPS in the bloodstream?
Fever, leukopenia, hypoglycemia, hypotension, and shock.
What is the first step in bacterial colonization?
Adherence.
What department does Emrah Ruh work in?
Department of Medical Microbiology and Clinical Microbiology.
How do some bacteria invade tissues?
Through the junctions between epithelial cells.
What natural defense mechanisms are present in the gastrointestinal tract?
Acid and bile.
What is the first step in bacterial colonization?
Adherence.
What are the effects of the cytokines released by IL-2?
Endothelial damage, acute respiratory distress syndrome, DIC, shock, and organ dysfunction.
What type of bacteria produce endotoxins?
Gram-negative bacteria.
How do IgG and IgM contribute to the immune response?
They activate the complement system via the classical pathway.
What are adhesins?
Molecules that enable bacteria to attach to host receptors.
What is phagocytosis in the context of bacterial virulence?
A process where macrophages engulf and digest bacteria, leading to cytokine secretion.
What are plasmids?
Small, circular DNA molecules that can replicate independently of chromosomal DNA in bacteria.
What is the role of adhesins in bacterial infections?
They facilitate adherence to host tissues.
What are siderophores?
Molecules specific for ferric iron that supply iron to the bacterial cell.
What type of bacteria produce endotoxins?
Gram-negative bacteria.
What are the two fates of bacteria after they invade a host cell?
Persist in an intracellular vacuole or escape to the cytosol.
How can bacteria spread after establishing an infection?
Directly through tissues or via the lymphatic system to the bloodstream.
How do Gram-positive bacteria release their toxins?
Directly into the environment.
What is a nonpathogen?
A microorganism that does not cause disease and may be part of the normal flora.
How does biofilm contribute to bacterial resistance?
It enables resistance to the host immune system and antibiotics.
What are exotoxins?
Toxins produced by bacteria that cause damage to host tissues.
What does IL-2 trigger the release of?
Several cytokines including TNF-a, IL-1, IL-8, and PAF.
What activities are associated with Type II exotoxins?
Phospholipase C, phospholipase D, and sphingomyelinase activity.
What is a key bacterial virulence factor that aids in colonization?
Adherence.
What can compromise the body's barriers?
Cuts, burns, and other injuries in the skin; tumors or ulcers in the bowel.
What structure do bacteria use to attach to host cells?
Pilus.
What follows colonization in the process of bacterial virulence?
Invasion.
What protective layer can enhance bacterial virulence?
Capsule.
What are the three main steps in bacterial virulence factors?
Colonization, Invasion, Nutrition.
What is the role of colonization in bacterial virulence?
It allows bacteria to establish themselves in the host environment.
Which family of bacteria can colonize the gastrointestinal tract?
Enterobacteriaceae.
What is pathogenicity?
The ability of an infectious agent to cause disease.
How do 'A' and 'B' enter the host cell?
By endocytosis.
What is the primary effect of bacterial virulence factors like exotoxins?
Producing damage.
Where are Pathogenicity Islands located?
On the bacterial chromosome.
What does bacteremia allow bacteria to do?
Spread widely in the body.
What antibacterial secretion is found in tears and mucus?
Lysozyme.
How is exotoxin synthesis generally enabled?
By genetic information transferred by plasmid or phage.
What are Type II exotoxins?
Membrane damaging toxins that hydrolyze membrane phospholipids.
What stimulates the release of large amounts of IL-2?
Activation of large amounts of T4 lymphocytes.
What is a route of entry associated with medical procedures?
Needlestick.
How do bacteria escape from the host immune response?
By employing various strategies to avoid detection and destruction by the immune system.
What activates the genes that control toxin synthesis?
Environmental factors.
What is the primary component of endotoxins?
Lipopolysaccharide (LPS).
What is a characteristic feature of channel or pore-forming toxins?
They create pores in cell membranes, leading to cell damage.
How do bacteriophages contribute to genetic exchange in bacteria?
They can transfer genetic material between bacteria during the process of infection.
What is a biofilm in the context of bacterial virulence?
A structured community of bacteria that enhances survival and resistance.
What is the role of adhesins in bacterial infections?
They facilitate adherence to host tissues.
What protective layer can enhance bacterial virulence?
Capsule.
What dental condition is associated with bacterial virulence factors?
Formation of dental caries.
What do bacteria excrete that causes dental caries?
Acidic products.
How do bacteria protect themselves against neutrophils?
By escaping from the phagosome.
What are superantigens?
A class of Type I exotoxins that activate a large number of T cells, leading to a strong immune response.
How do endotoxins affect fever in hosts?
They usually produce fever by the release of interleukin-1 and other mediators.
What are Type III toxins?
A-B toxins that consist of an active (A) and a binding (B) component.
Can endotoxins be converted to toxoids?
No, endotoxins are not converted to toxoids.
What are Type III toxins?
A-B toxins that consist of two components: an A (active) component and a B (binding) component.
What are Type II toxins?
Membrane damaging toxins that disrupt the integrity of host cell membranes.
What mechanism do bacteria use to inhibit complement activation?
Inhibition of the membrane attack complex (MAC).
What is antigenic mimicry in the context of bacterial virulence?
When bacteria mimic host antigens to evade immune detection.
What is the title of Emrah Ruh at Near East University?
Assoc. Prof.
What is the first step in the infectious process for bacteria?
Attachment or adherence to host cells.
What is the role of IgG in the immune response?
IgG acts as an opsonin and causes opsonization.
What are endotoxins?
Lipopolysaccharides (LPS) that are endotoxins of Gram-negative bacteria.
What is the role of pili in bacterial virulence?
Pili facilitate adherence to host cells by being compatible with glycoprotein and glycolipid receptors.
What is the role of biofilms in bacterial colonization?
They form a slimy coat on solid surfaces and facilitate adherence.
What role does mucus play in the respiratory tract?
It helps trap pathogens and particles.
What are A-B toxins?
Exotoxins consisting of an active 'A' subunit and a binding 'B' subunit.
What is the role of adhesins in bacterial infections?
They facilitate adherence to host tissues.
What role does binding protein H play in relation to bacterial capsules?
It helps in evading the immune response, especially in capsules rich in sialic acid.
What component of endotoxins is responsible for primary toxicity?
Lipid A.
What are endotoxins?
Lipopolysaccharides (LPS) that are endotoxins of Gram-negative bacteria.
How do endotoxins contribute to bacterial virulence?
By causing damage to host tissues and triggering inflammatory responses.
What is a characteristic of the outer membrane of Gram-negative bacteria?
Resistance to lysozyme, acid, and bile.
What type of bacteria primarily produce endotoxins?
Gram-negative bacteria.
What does masking pathogen-associated molecular patterns achieve?
It helps the bacteria evade detection by the immune system.
What type of toxins are classified as membrane-damaging toxins?
Exotoxins, specifically Type II: Membrane damaging toxins.
What is a key characteristic of endotoxins compared to exotoxins?
Endotoxins are heat-stable and not secreted, while exotoxins are often heat-labile and secreted by bacteria.
What does producing damage in the host entail?
It involves harming host tissues or disrupting normal physiological functions.
What is a portal of entry for pathogenic bacteria related to sensory organs?
Eyes.
What is toxigenicity?
The ability of a microorganism to produce a toxin.
How do bacteria escape from adaptive immunity?
Through mechanisms like antigenic shift and antigenic mimicry.
How do bacteria escape from adaptive immunity?
Through mechanisms like antigenic shift and antigenic mimicry.
What receptors do LPS interact with on immune cells?
Toll-like receptor 4 (TLR-4).
What are bacterial virulence factors?
Factors that enable bacteria to damage the host.
What is the function of immunoglobulin proteases in bacterial virulence?
They degrade antibodies, aiding in immune evasion.
What role does LPS play in the activation of plasminogen?
LPS activates plasminogen to plasmin, which converts fibrin to fibrin split products.
How do bacteria trigger macrophage apoptosis?
By using specific virulence factors.
What is the significance of binding to the Fc region of antibodies?
It helps bacteria evade opsonization and phagocytosis.
What is the function of the A component in A-B toxins?
It is responsible for the toxic effect.
What is one way bacteria can trigger macrophage apoptosis?
By releasing specific factors that induce cell death.
What are bacterial virulence factors?
Factors that enable bacteria to damage the host.
What is a bacterial virulence factor that helps escape from innate immunity?
Capsule.
What type of toxins are associated with bacterial virulence factors?
Exotoxins.
What is an example of a Type I exotoxin?
Superantigens.
What role do adhesins play in bacterial infections?
They facilitate the attachment of bacteria to host cells.
What is a key bacterial virulence factor that aids in colonization?
Adherence.
What is a biofilm in the context of bacterial virulence?
A structured community of bacteria that enhances survival and resistance.
What structure do bacteria use to attach to host cells?
Pilus.
Which part of the body can pathogenic bacteria enter through capillaries?
The bloodstream.
How do endotoxins contribute to bacterial virulence?
By producing damage to the host.
What is the first step in bacterial colonization?
Adherence.
What role does glycosyltransferase play in bacterial adherence?
It converts glucose on the tooth surface to dextran, a component of glycocalyx.
What does adherence to host cells refer to?
The ability of pathogenic bacteria to attach to the cells of the host.
What is meant by invasion of host cells and tissues?
The ability of pathogenic bacteria to penetrate and multiply within host cells and tissues.
What are the two main types of bacterial virulence factors discussed?
Exotoxins and endotoxins.
What are endotoxins primarily composed of?
Lipopolysaccharides (LPS).
How do bacteria protect themselves against neutrophils?
By inhibiting complement activation.
What are superantigens?
A class of Type I exotoxins that activate a large number of T cells, leading to a strong immune response.
What mechanism do bacteria use to escape from the phagosome?
Inhibition of complement activation.
What can result from impaired perfusion of essential organs due to LPS?
Intravascular coagulation and death from massive organ dysfunction.
What is a key difference in the genetic control of exotoxins and endotoxins?
Exotoxins are frequently controlled by extrachromosomal genes, while endotoxins are directed by chromosomal genes.
What is a bacterial virulence factor that helps escape from innate immunity?
Capsule.
What are Type III toxins?
A-B toxins that consist of two components: an active component and a binding component.
What is an endotoxin?
A toxin that is part of the bacterial cell wall and is released upon cell lysis.
How do pore-forming toxins function in relation to the type III secretion system?
They are involved in the functioning of the type III secretion system.
What occurs during recombination involving extrachromosomal DNA?
Recombination between extrachromosomal DNA and the chromosome.
What is the third step in bacterial virulence factors?
Nutrition.
What is a route of entry that can occur through sexual contact?
Sexual transmission.
What happens to the cell membrane due to pore-forming toxins?
They damage the cell membrane, allowing bacteria to leave the cell.
What are some targets of A-B toxins?
Cyclic adenosine monophosphate (cAMP), ADP-ribosylation, Rho proteins, metalloproteinase action, and RNA.
What do some bacteria form on host cells to aid in adherence?
Biofilms.
What are Type III exotoxins composed of?
Two subunits: 'A' and 'B'.
Which bacterium is an example that causes tooth decay?
Bacteria that utilize glycosyltransferase to convert glucose to dextran.
What role does virulence play in bacterial strains?
It differentiates the pathogenic strain of a species.
What is a bacterial virulence factor that helps escape from innate immunity?
Capsule.
What is toxigenicity?
The ability of bacteria to produce toxins that can harm the host.
How do pathogenic bacteria evade the host's immune system?
By employing various strategies to avoid detection and destruction by immune cells.
What are Type I exotoxins?
Pyrogenic exotoxins that can induce fever.
What are exotoxins known for?
They usually bind to specific receptors on cells.
What protects bacteria against neutrophils?
Capsule and other virulence factors.
What is antigenic mimicry?
A strategy used by bacteria to evade the immune response by resembling host antigens.
How do bacteria protect themselves against neutrophils?
By escaping from the phagosome and inhibiting neutrophil activity.
What are Type III toxins?
A-B toxins that consist of two parts: an active component and a binding component.
What do some bacteria have that allows them to invade the body?
Means to compromise the barrier.
Can biofilms consist of multiple species?
Yes, they may consist of one or more species.
How does the capsule inhibit opsonization?
By masking C3b.
What role do transposons play in bacterial genetics?
They are DNA sequences that can change their position within the genome, facilitating genetic variation.
What does 'escape from innate immunity' refer to?
Protection from phagocytosis and the lytic activity of the complement system.
What is one effect of ADP-ribosylation by A-B toxins?
It modifies target proteins, affecting their function.
What are superantigens classified as?
Type I exotoxins.
What is the function of 'Part B' in Type III exotoxins?
'Part B' binds to the receptor of the host cell.
What is a biofilm in the context of bacterial virulence?
A structured community of bacteria that enhances survival and resistance.
What process allows bacteria to penetrate host tissues?
Invasion.
What is the role of the capsule in bacterial virulence?
It helps bacteria evade the host's immune response.
What is one way bacteria can trigger macrophage apoptosis?
By releasing specific factors that induce cell death.
What is an endotoxin?
A toxin that is part of the bacterial cell wall and is released upon cell lysis.
How do bacteria escape from adaptive immunity?
Through mechanisms like antigenic shift and antigenic mimicry.
What role do immunoglobulin proteases play in bacterial virulence?
They degrade antibodies, aiding in immune evasion.
What is the function of A-B toxins?
The A component is responsible for the toxic effect, while the B component binds to the host cell.
What type of iron do siderophores specifically target?
Ferric iron.
What process allows bacteria to penetrate host tissues?
Invasion.
Can bacteria pass through the body's barriers?
Yes, bacteria can pass through the barriers.
What is inhibited to prevent phagosome formation?
Inhibition of phagosome formation.
What is transmissibility in the context of pathogenic bacteria?
The ability of bacteria to be spread from one host to another.
How do bacteria adhere tightly to tooth enamel?
By using their glycocalyx.
What do bacteria develop to survive phagocytic death?
Resistance against phagocytic death.
What mechanism do bacteria use to inhibit complement activation?
Inhibition of the membrane attack complex (MAC).
How do bacteria bind to the Fc region of antibodies?
To prevent opsonization and enhance evasion of the immune response.
What are exotoxins?
Toxins secreted by bacteria that can cause damage to the host.
What is the function of immunoglobulin proteases released by bacteria?
To degrade antibodies and impair the immune response.
What are superantigens?
A class of Type I exotoxins that activate a large number of T cells, leading to a strong immune response.
What is the function of immunoglobulin proteases released by bacteria?
To degrade antibodies and evade the immune response.
How do bacteria escape from the host immune response?
By employing various strategies to avoid detection and destruction by the immune system.
What can result from the exchange of genetic information between bacteria?
The transfer of virulence factors.
How can pathogenic bacteria enter the body through the skin?
Through cuts or abrasions.
What is the role of antigen presenting cells (APC) in normal conditions?
APCs present antigens to MHC II.
What happens to bacterial cells of the same or different species in the glycocalyx?
They become entrapped and form plaque on the tooth surface.
What is an endotoxin?
A toxin that is part of the bacterial cell wall and is released upon cell lysis.
What are Type I exotoxins?
Pyrogenic exotoxins that can induce fever.
How are toxoids related to exotoxins?
Toxoids are converted from exotoxins and are used to immunize.
What are endotoxins associated with in bacterial infections?
They are associated with producing damage in the host.
What is disseminated intravascular coagulation (DIC)?
A frequent complication of Gram-negative bacteremia that can also occur in other infections.
How does LPS activate the coagulation cascade?
LPS activates factor XII, leading to the conversion of fibrinogen to fibrin.
Do endotoxins usually produce fever in hosts?
Yes, they usually produce fever, unlike exotoxins.
What effect does LPS have on platelets?
LPS causes platelets to adhere to vascular endothelium, leading to occlusion of small blood vessels.
What are the consequences of LPS-induced occlusion of small blood vessels?
It can cause ischemic or hemorrhagic necrosis in various organs.
What is the role of the capsule in bacterial virulence?
It helps bacteria evade the host's immune response.
What is the primary component of endotoxins?
Lipopolysaccharide (LPS).
How does the complement system relate to bacterial virulence?
It is activated by cytokines and the bacterium itself, which can lead to bacterial destruction.
What is one way bacteria escape from innate immunity?
By escaping from the phagosome.
What does virulence refer to?
The quantitative ability of an agent to cause disease, involving adherence, invasion, and toxigenicity.
Why is free iron in the ferric form (Fe 3+) considered highly insoluble?
Because it forms hydroxides, carbonates, and phosphates.
What process do bacteria inhibit to escape from the phagosome?
Inhibition of phagolysosome formation.
What is a bacterial virulence factor that helps escape from innate immunity?
Capsule.
What are exotoxins?
Toxins secreted by bacteria that can cause damage to the host.
What are exotoxins?
Toxins secreted by bacteria that can cause damage to the host.
Which cells are involved in the response to LPS?
Macrophages, monocytes, and other cells of the reticuloendothelial system.
How do endotoxins differ in immunogenicity compared to exotoxins?
Endotoxins are weakly immunogenic, while exotoxins are highly antigenic.
What is antigenic mimicry in the context of bacterial virulence?
When bacteria mimic host antigens to evade immune detection.
What is the function of the Membrane Attack Complex (MAC) in the immune response?
To lyse bacterial cells, which some bacteria inhibit.
What is a characteristic of endotoxins regarding receptor binding?
Specific receptors are not found on cells for endotoxins.
What are exotoxins?
Toxins secreted by bacteria that can cause damage to the host.
What are Type II toxins?
Membrane damaging toxins that disrupt the integrity of host cell membranes.
Which sensory organ can serve as a portal of entry for pathogenic bacteria?
Ears.
How do bacteria resist the acidic environment of the phagosome?
By inhibiting phagosome acidification.
What is inhibited to prevent phagosome maturation?
Inhibition of phagosome maturation.
What are bacterial virulence factors?
Factors that enable bacteria to damage the host.
What is the role of the capsule in bacterial virulence?
It helps bacteria evade the host's immune response.
What is the role of antitoxin in relation to exotoxins?
Antitoxin neutralizes the exotoxin.
What is antigenic mimicry in bacterial virulence?
When bacteria mimic host antigens to evade immune detection.
What is the toxicity level of exotoxins in laboratory animals?
Highly toxic.
What are superantigens?
A type of Type I exotoxin that activates a large number of T-cells, leading to a strong immune response.
What are bacterial virulence factors?
Factors that enable bacteria to damage the host.
How do exotoxins affect the immune system?
They are highly antigenic and stimulate the formation of high-titer antitoxin.
What is one way bacteria can trigger macrophage apoptosis?
By releasing specific factors that induce cell death.
What cytokines are released in response to LPS?
IL-1, TNF, and other cytokines.
What are Type II toxins?
Membrane damaging toxins that disrupt the integrity of host cell membranes.
How do bacteria bind to the Fc region of antibodies?
To prevent opsonization and enhance evasion of the immune response.
What are Type I exotoxins?
Pyrogenic exotoxins that can induce fever.
What is the toxicity level of endotoxins in laboratory animals?
Moderately toxic.
What are Type II toxins?
Membrane damaging toxins that disrupt the integrity of host cell membranes.
What is the role of the B component in A-B toxins?
It binds to the host cell and facilitates the entry of the A component.
How do bacteria bind to the Fc region of antibodies?
By using specific proteins that interfere with antibody function.
What are Type I exotoxins?
Pyrogenic exotoxins that can cause fever and immune response.
