Vaccines & Antibiotics (Ch. 27, Lec. 24)
Thursday, December 10, 2020 12:00 PM
LEC24 RQ
The primary antibody response differs from the secondary antibody response in that
• Terms of disease occurrence: in the primary response, plasma cells differentiate from naive B cells, whereas in
• Endemic disease: occurs at a steady, predictable freq. the secondary response, plasma cells may differentiate from memory B cells.
• Epidemic disease: sudden INC in disease occurrence above the expected level, usually in
clusters. Ex. B. Pertussis(whooping cough) in OC area. The oral polio vaccine is an example of a __________ vaccine.
○ Outbreak: a local epidemic. Ex. Salmonella food poisoning. live attenuated
• Pandemic disease: a worldwide epidemic. Ex. Influenza virus. -Some vaccines, such as the polio vaccine, need to provide a live microbe to produce
• Index case: the first case of the disease in an epidemic. Patient zero.
an immune response in the correct compartment to ensure that the virus cannot be
• Public health surveillance:
○ In early 1900s, leading cause of death in the US was infectious disease. shed from the gut if feces contamination of the water supply is a concern.
○ Yet surveillance identified sources/risks of infection. -> PH measures reduced
disease prevalence: water treatment, strict sanitation, antimicrobials, beginning A(n) __________ vaccine will produce a cell-mediated immune response.
vaccine development. live, attenuated organism
○ Today, the US leading cause of death is heart disease and other vascular/metabolic
diseases. Penicillin inhibits peptidoglycan synthesis in bacterial cell walls. Humans do not have
• Tracking infectious disease: cell walls. This is an example of
○ In 1940s, PH effort extended to population-based methods of monitoring disease. -> selective toxicity.
Can see trends in disease, then disseminate information to reduce spread.
○ Now, response to an outbreak: (1) epidemiologist correlate the disease w/ an Suppose an exponentially growing culture of bacteria is treated with a potential
infectious organism, (2) physicians/nurses collect pt specimens, (3) clinical
antimicrobial compound. Over the next few hours, cell doubling stops (untreated, control
microbiologists isolate /identify the causative organism.
• Out of all the individuals in a population: cultures continue doubling), but the cells remain metabolically active. This antimicrobial
○ Incidence: # of new cases. compound is
○ Prevalence: total # of cases. bacteriostatic.
○ Even if incidence is low, prevalence can be high (newly infected people are living
longer).
• Recent INC in mortality rates, esp in the US. Outlier is the Spanish Flu of 1918.
• The US PH System is composed of:
○ Local and State level: public health laboratories, county health dept.
○ National level: CDC--Center of Disease Control and Prevention
• Control of epidemic:
1. Reduction/elimination of the source: treat/quarantine infected individuals, reduce likelihood
of transmission, control/remove reservoirs.
2. INC level of herd immunity: vaccination programs.
a. Herd immunity: pop resistance to infection bc large percentage(>70%) of said pop is
immune.
b. Factors that affect her immunity: introduction of new susceptible individuals,
antigenic shift or drift in pathogen-- individuals that may not be immune to these new
strains.
3. Sanitation methods: food safety(pasteurization, food inspection), water purification and
chlorination, insect vector control.
○ Dr. James in UCI molecular Bio dept has genetically-engineered male mosquitoes.
When males mate w/ females, daughters (female offspring) cannot fly due to wing
mutation. -> flightless females die, reducing the mosquito population. Can control
dengue fever!
• Smallpox is the only human disease to be eradicated. Only present in humans, no
reservoirs to cause incidence.
• Vaccine: microbial Ag used to induce protective immunity.
○ Goal is to induce Ab and T cell-mediated responses to protect the host from future
infection.
○ Administered w an adjuvant(vaccine ingredient) to maximally stimulate immunity. Ex.
Heat-killed bacteria.
○ Immunization: result achieved by successful delivery of a vaccine that has stimulated
immunity.
• Edward Jenner and Vaccine Development:
○ Dr. Jenner observed that ppl who had cowpox(vaccinia) never became sick w/
smallpox(variola), i.e. milkmaids w/ cowpox infection.
, ○ First case of vaccination: In 1796, Jenner injected cowpox-infected skin tissue into
the arm of James Phipps--causing mild symptoms of cowpox. Then inoculated
Phipps w/ smallpox, and Phipps did NOT develop the disease. -> Vaccination
process known as variolation!
• Types of vaccine:
○ Whole cell: consists of a whole microorganism (bacteria/virus).
• Inactivated: microbe is killed by heat/formaldehyde. Ex. Flu shot injection
• Epitopes present on killed antigen are used for immunity.
• Attenuated/Weakened: live microbes that have been altered for reduced
virulence. Ex. Flu mist
○ Subunit: consists of purified macromolecules from pathogens(polysaccharides,
surface antigens, toxoids).
○ Recombinant vector / DNA: consist of individual genes or DNA from pathogens. Ex.
HBV/Herpes B.
• Primary and secondary Ab responses:
○ Primary antibody response:
• Via disease or vaccination.
• Ab appear in the serum after several days.
• B cells that bind Ag make the Ab.
• Some B cells become memory B cells.
○ Secondary antibody response:
• Via second exposure to pathogen to pathogen or booster does.
• Ab appear in blood within hours. -> much larger and quicker response!
○
• Generation of Attenuated Vaccines:
○ Methods for generating attenuated(avirulent) vaccines:
• Deletion of specific virulence genes.
• Serial passage in a dif host organism -> adaptation to the new host and
reduced virulence in the orig host.
○ Benefit: induce stronger immunity than inactivated vaccines by providing more Ag.
(Viral copies are made via replication that immune system can fight against.)
○ Drawback: risk of reversion to virulence; can NOT be given to immunocompromised
hosts.
• How is the flu virus vaccine produced?
○ (Inactivated) Live virus of a chosen strain is injected into embryonated chicken eggs.
○ Virus infectivity is destroyed using formalin and disrupted using detergents to release
Ag(w/ specific epitopes that we can develop Ab for) that are used for vaccine.
• Detergent can disrupt the actual structure of the HA(hemagglutinin) that is
recognized by antibodies…have to consider during vaccine development.
○ (Attenuated) Same procedure, but would use a strain that does not cause disease.
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