63 Questions
What are the two ways to achieve immunity to infectious microorganisms?
Natural and artificial means
How can immunity to infectious microorganisms be acquired through natural processes?
B+C
What is an example of artificial means to achieve immunity to infectious microorganisms?
B+C
Passive immunization occurs when:
Antibodies are transferred across the placenta to the developing fetus.
What is the outcome of passive immunization?
Transient protection for the recipient
How do maternal antibodies provide passive immunity to the developing fetus?
By Maternal antibodies present in colostrum and milk
What is a characteristic of passive immunization achieved by injecting preformed antibodies?
It provides transient protection
Which of the following microorganisms provide passively acquired protection to the developing fetus?
Diphtheria, tetanus, streptococci, rubella, mumps, and poliovirus.
Passive immunization activates the immune system to generate a memory response.
False
Under what conditions is passive immunization required?
When there is deficiency in synthesis of antibody due to B-cell defects
What situation may necessary passive immunization?
Exposure or likely exposure to a disease causing complications
What is a potential reason for using passive immunization?
To ameliorate the effects of pathogens through preformed antibodies
When might passive immunization be necessary?
When there is infection by pathogens whose effects may be ameliorated by antibody
What is the primary goal of active immunization?
Elicit protective immunity and immunologic memory
How can active immunization be achieved artificially?
By administration of a vaccine
What is the outcome of passive immunization?
Provide transient protection
What role do antigen-reactive T and B cells play in active immunization?
Result in the formation of memory cells
What is the primary goal of active immunization?
To elicit protective immunity and immunologic memory
How can active immunization be achieved?
By natural infection with a microorganism
What role do antigen-reactive T and B cells play in active immunization?
They result in the formation of memory cells
How does passive immunization differ from active immunization?
It provides transient protection
What does the development of an immune response indicate?
A state of protective immunity has been achieved
What must vaccine designers recognize when activating different branches of the immune system?
The differences between humoral and cell-mediated activation
Under what condition does the development of an immune response not necessarily lead to protective immunity?
When the pathogen has a long incubation period
What is the primary goal of whole-organism vaccines?
To provide prolonged immune-system exposure to individual epitopes
Which of the following is an example of a whole-organism vaccine?
B+C
What is the purpose of prolonged immune-system exposure in whole-organism vaccines?
A+B
How are microorganisms attenuated for vaccines?
They are weakened to lose their ability to cause disease
What is the primary goal of inactivated whole-pathogenic organism vaccines?
To maintain the structure of epitopes on surface antigens
How is inactivation of the pathogen achieved in whole-organism vaccines?
By using heat or chemicals
Which of the following is used for chemical inactivation of pathogens?
Formaldehyde
Which of the following is an example of a disease that can be prevented by an inactivated whole-organism vaccine?
All of the above
What is the rationale for vaccines consisting of purified capsular polysaccharides?
To increase the ability of macrophages and neutrophils to phagocytose pathogens
What is one limitation of polysaccharide vaccines?
They are unable to activate TH cells and do not result in class switching or memory cells
What type of immune response do inactivated whole-pathogenic organism vaccines elicit?
Thymus independent type 2 (TI-2) response
Which two diseases are mentioned as examples?
Pneumonia and Meningitis.
Purified capsular polysaccharides can be used as vaccines against Streptococcus pneumonia and Neisseria meningitides.
True
Polysaccharide vaccines are capable of activating TH cells.
False
Passive immunization involves injecting preformed antibodies.
True
Polysaccharide vaccines activate B cells in a thymus independent type 2 (TI-2) manner.
True
What is the primary advantage of conjugate vaccines like the Haemophilus influenzae type b (Hib) vaccine?
They enable class switching from IgM to IgG
What kind of vaccine is Haemophilus influenzae type b (Hib) vaccine?
Conjugate vaccine
Which type of cells does the Hib vaccine activate, leading to class switching from IgM to IgG?
Helper T cells
How are toxoids for diphtheria and tetanus vaccines produced?
By purifying the bacterial exotoxin and inactivating it with formaldehyde to form a toxoid
What is the primary function of vaccination with toxoids?
Inducing anti-toxoid antibodies capable of neutralizing the effects of the toxin
How can large quantities of exotoxin be prepared for vaccine production?
Producing, purifying, and subsequently inactivating large quantities of the exotoxin by recombinant methods
What is the process of inactivating the toxin with formaldehyde to form a toxoid called?
Chemical detoxification
How is the hepatitis B vaccine produced using recombinant DNA technology?
The gene for the major surface antigen of the hepatitis B virus is cloned and expressed in yeast cells
What is the primary application of recombinant DNA technology in vaccine production?
Producing vaccines for viral, bacterial, and protozoan pathogens
What is the first recombinant antigen vaccine approved for human use?
Hepatitis B vaccine
What is the primary function of recombinant-vector vaccines?
Introduce genes of major antigens into attenuated viruses or bacteria
Which virus was used to eradicate smallpox?
Vaccinia virus
How many genes does the vaccinia virus have?
Approximately 200 genes
What happens when the genetically engineered vaccinia virus expresses a gene product?
It serves as a potent immunogen in the host
How is the gene that encodes the desired antigen inserted into the vaccinia virus genome?
Inserted into a plasmid vector adjacent to a vaccinia promoter and flanked by the vaccinia thymidine kinase (TK) gene
What is the role of bromodeoxyuridine (BUdr) in the process of selecting cells containing the recombinant vaccinia virus?
It kills TK cells
What is the result of homologous recombination at the site of the nonessential TK gene?
Creation of a TK-recombinant virus
What is the primary advantage of DNA vaccines?
They cause prolonged expression of the antigen and generate significant immunological memory
What type of response do DNA vaccines elicit?
Both humoral antibody response and cell-mediated response
What is the outcome of DNA vaccines inducing prolonged expression of the antigen?
Significant immunological memory is generated
DNA vaccines lead to both humoral antibody response and a cell-mediated response.
True
DNA vaccines do not induce immunological memory.
False
DNA vaccines can lead to prolonged expression of the antigen.
True
Test your knowledge about immunity to infectious microorganisms, achieved through active or passive immunization. Explore the processes of natural and artificial acquisition of immunity, including transfer from mother to fetus, previous infection, injection of antibodies, and vaccines.
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