Exam 3 Vaccines Flashcards
(34 cards)
Whats a monoclonal antibody?
When an antibody recognizes just a single antigen it is referred to as a monoclonal antibody. It is a protein administered directly to the body to protect it from disease, so that it can immediately act and fight off the infection.
What are vaccines?
A vaccine is a suspension of organisms or fractions of organisms used to induce immunity.
What are the different types of vaccinations?
Attenuated vaccines are made of weakened or damaged live microbes, that are generally unable to cause disease in their weakened state. They produce lifelong immunity, inducing both cell mediated and humoral immune responses. However, because they contain living microbes, they could be dangerous to immunocompromised individuals if the microbe reverts to a virulent state.
Inactivated vaccines are formulated from dead microbes that are unable to produce disease. However, they are slightly less effective than attenuated vaccines, inducing only a humoral immune response. To maintain their effectiveness over time, booster doses are often required.
Subunit vaccines are produced from certain parts of the microbe. They don’t require the complete organism in order to be effective.
mRNA vaccines - mRNA delivered to cells inside lipids. Cells translate it to make pathogen proteins. Activates T cells (both helper and cytotoxic) and B cells.
Recombinant protein vaccines - make pathogen surface proteins by adding the genes to a plasmid and using the bacteria to make it. Inject the proteins into body. Activates helper T cells and B cells but not cytotoxic T cells.
How do vaccines work?
Vaccinations promote long term immunity by inducing a primary immune response, which results in the production of long lasting memory B cells. If these memory cells encounter the same antigen in the future, they rapidly differentiate into antibody-producing plasma cells, which produce the antibodies observed in the secondary immune response.
Are vaccines worth the risk?
Although rare, there can be side effects. MMR vaccine can produce allergic reactions, or cause disease if it’s an attenuated vaccine. But this is 1 in a million. Most experts agree the benefits outweigh the risks. Because of the introduction of vaccinations, many deadly diseases are no longer endemic in the US.
What is HIV and how does it cause AIDS?
Human immunodeficiency virus is an enveloped, single stranded RNA virus. It uses its glycoproteins, GP41 and GP120 to bind target cells. It specifically infects T-helper cells containing CD4 membrane receptors. During an active HIV infection, the virus replicates inside the helper T cell, causing the cell to release viruses. If many viruses are released all at once, the T cell will lyse and die. The liberated viruses infect other CD4+ helper T cells. As the virus multiplies, the patients CD4+ T helper cell count decreases. If it falls below 200 cells per microliter, the patient won’t be protected by an operational immune system. This condition, clinically known as AIDS, makes the person vulnerable to oportunistic infections,
How is an HIV infection diagnosed?
ELISA and western blood tests which test for antibodies, not for the virus itself. The baby was positive for ELISA and Western blot but negative for PCR (which tests for viral RNA) because baby got the antibodies from mom (naturally acquired passive immunity) but not the virus.
How does a person get HIV?
- Unprotected sex
- Passing infected blood or body fluids like semen and blood
- Mother to child sometimes through natural birth as well as breast feeding
How can HIV transmission be prevented?
Take antiretroviral drugs. These fall into 4 different categories, each one preventing a different step of the HIV replication cycle.
Fusion inhibitors prevent HIV from binding the CD4 receptor in helper T cells.
Reverse transcriptase inhibitors prevent the conversion of viral RNA to viral DNA
Integrase inhibitors prevent the fusion of viral DNA and host cell DNA
Protease inhibitors stop large viral proteins from cleaving into smaller viral proteins, this helps prevent viral assembly and release from infected cells.
Although antiretroviral drugs prevent HIV replication and cell death, they do not remove the virus entirely, so there is still a risk of transmission
What are fimbriae?
Fimbriae are hair-like structures bacteria use to attach to host cells.
What would antibodies binding to fimbriae do?
Block adhesion to epithelial cells
• Neutralize the bacteria’s ability to colonize
• Mark them for phagocytosis by immune cells (opsonization)
TLDR Prevents infection by stopping the bacterium from attaching to host cells.
What would the effect of adding antibodies against the host cell mannose be?
Mannose is a sugar molecule found on the surface of host epithelial cells.
• Some bacteria (like E. coli) have fimbriae (FimH) that bind to mannose for attachment.
• Antibodies targeting mannose would:
• Mask the mannose sites so bacteria can’t bind
• Reduce bacterial adhesion and colonization
TLDR Conclusion: Prevents infection by blocking bacterial binding sites on host cells.
shortly explain how a person who recovers from a disease can attend to others with the disease without fear of contracting it
A person who recovers from a disease often develops memory cells and antibodies that recognize and fight the same pathogen if exposed again. This immunity helps protect them from getting reinfected, especially short term, allowing them to care for others without fear of contracting the disea
A patient had life-threatening salmonellosis. Despite the patient’s immune system and antibiotics breaking down bacteria cells, she still exhibits life-threatening symptoms.
She was successfully treated with anti Salmonella. Why did this treatment work, when antibiotics and the patient’s own immune system failed?
Salmonellosis is an infection with a bacteria called Salmonella, Salmonella live in the intestinal tracts of animals, including birds. Salmonella are usually transmitted to humans by eating foods contaminated with animal feces.
“Antibiotics and immunity can cause gram-negative cells to lyse, releasing cell wall fragments. This exposes the body to more endotoxin. The woman’s life-threatening condition was due to endotoxin shock. Monoclonal antibodies removed the cell walls.”
Antibodies against Salmonella may have worked because:
• They neutralized the toxins directly.
• They prevented further bacterial attachment or invasion.
• They enhanced clearance without causing massive inflammation.
On a vacation to Australia, Riley was bitten by a poisonous sea snake.
Quickly transported to a nearby emergency department, Riley received an antivenin injection and survived.
* What is antivenin?
* How is it obtained?
* How did it lead to Riley’s survival?
What is antivenin?
Antivenin (or antivenom) is a treatment made of antibodies that neutralize venom from a poisonous animal bite or sting.
How is it obtained?
Antivenin is made by:
1. Injecting a small, safe amount of venom into an animal (usually a horse or sheep).
2. The animal’s immune system makes antibodies against the venom.
3. Blood is drawn from the animal, and the antibodies are purified to make antivenin.
How did it lead to Riley’s survival?
The antivenin contained ready-made antibodies that immediately neutralized the snake venom, stopping it from damaging Riley’s cells and organs. This fast action gave Riley’s body time to recover and survive.
Describe three methods by which a person might acquire antibodies against the HIV virus.
- Natural infection: If a person is exposed to HIV and becomes infected, their immune system produces antibodies against the virus.
- Vaccination (in development): Though there is currently no widely available HIV vaccine, experimental vaccines aim to stimulate the immune system to produce HIV-specific antibodies without causing infection.
- Passive immunity: A person can receive HIV antibodies through injection (e.g., monoclonal antibody therapy), providing temporary protection or treatment without producing the antibodies themselves.
- Mother-to-child transfer: Babies born to HIV-positive mothers may have HIV antibodies in their blood. These are passively transferred across the placenta during pregnancy, but don’t necessarily mean the baby is infected.
In your role at a local public health clinic, you come across parents of a three-month-old contemplating skipping vaccinations for their child. What worries might they have about vaccine safety? As someone studying microbiology and working in public health, what would you advise these parents about the dangers of forgoing vaccinations for their child?
Parents may worry about side effects, vaccine ingredients, or false claims linking vaccines to autism. As someone studying microbiology, I would explain that vaccines are thoroughly tested for safety and protect against serious, sometimes deadly diseases. Skipping vaccines puts their child—and others—at risk, especially infants too young to be vaccinated and people with weakened immune systems.
A healthcare professional experienced a needlestick accident while extracting blood from a patient with AIDS. Despite laboratory tests showing negative results for infection in the worker’s blood, it’s important to understand he could still be at risk of infection. Explain why he could still be at risk and advise how his health care should be monitored.
He could still be at risk because the virus may be in the window period—a time when HIV is present but not yet detectable by standard tests. He should receive post-exposure prophylaxis (PEP) immediately and undergo follow-up testing at intervals (e.g., 6 weeks, 3 months, and 6 months) to monitor for HIV infection.
- Akyo and Malik were preparing for a microbiology test.
“ Let’s focus on the MMR vaccine,” said Akyo.
“Sure, what about it?” Malik responded. “It guards against mumps, measles, and rubella.”
“It’s administered around 12–15 months old. But what if a younger baby is exposed to measles? Professor Kemeny mentioned measles is highly contagious, affecting 90% of non-immune contacts.”
“I believe infants get some protection from their mothers,” Malik said, searching for confirmation in his textbook.
“Right. They receive antibodies through the placenta and breastfeeding. But that protection doesn’t last long, does it?” Akyo joined the search.
“It aids the infants until they’re old enough for their own immunization. Mothers need to generate antibodies themselves, either through measles exposure or vaccination,” Malik explained.
“I’ve read that measles can increase susceptibility to other infections,” Malik added. “It’s a form of immunosuppression.”
“How does that happen?” Akyo inquired.
“Recent studies suggest measles virus targets and eliminates memory B and T cells.”
“Yikes! That’s concerning,” Akyo remarked.
“Indeed. But it also implies the MMR vaccine could offer broader protection,” Malik concluded.
“And that’s a positive outcome,” Akyo agreed.
Questions
* Why is it advised against administering the MMR vaccine to infants under the age of one?
* If the measles virus does infect and destroy memory B and T cells, how might this elevate the likelihood of dying from other infectious diseases?
- The MMR vaccine isn’t given to infants under one year because maternal antibodies can interfere with the vaccine, making it less effective. The vaccine works best once those maternal antibodies wane.
- If measles destroys memory B and T cells, it erases the body’s “immune memory,” making the person more vulnerable to infections they were previously protected against. This increases the risk of dying from other diseases after a measles infection.
Palivizumab is used to treat respiratory syncytial virus (RSV) disease. This antiviral drug is a(n) _
A) toxoid
B) monoclonal antibody
C) vaccine
D) immunosuppressive
E) nucleoside analog
B) monoclonal antibody
Monoclonal antibodies (mABs) are often used in diagnostic tests and disease treatments because (select the most inclusive answer)
A) They are highly specific.
B) They can be produced in large quantities.
C) They contain a mixture of antibodies.
D) They are highly specific and they can be produced in large quantities.
E) They are highly specific, they can be produced in large quantities, and they contain a mixture of antibodies.
D) They are highly specific and they can be produced in large quantities.
Which of the following is not an advantage of live attenuated vaccine agents?
A) They elicit lifelong immunity.
B) They stimulate both cell-mediated and humoral immune responses.
C) They usually revert to virulent forms.
D) They require few or no booster immunizations.
E) The immune response generated by the vaccine closely mimics a real infection.
C) They usually revert to virulent forms.
Experience has shown that attenuated vaccines tend to be more effective than inactivated vaccines. Why?
A. Attenuated vaccines use whole microbes that have been killed; while inactivated vaccines use weakend microbes.
B. Attenuated vaccines induce an immune response; while inactivated vaccines do not.
C. Attenuated vaccines only induce a humoral response; while inactivated vaccines induce both a cellular and a humoral immune response.
D. Attenuated vaccines induce both a cellular and humoral immune response; while inactivated vaccines only induce humoral immunity.
D. Attenuated vaccines induce both a cellular and humoral immune response; while inactivated vaccines only induce humoral immunity.
The surface of a pathogen has two different antigens. What happens when the specific immune system encounters this pathogen?
A. B cells carrying receptors to the pathogen generate antibodies that recognize the pathogen.
B. B cells carrying receptors for Antigen 1 produce antibodies that recognize Antigen 1, while different B cells carrying receptors for Antigen 2 produce antibodies that recognize Antigen 2.
C. B cells carrying receptors for both Antigen 1 and Antigen 2 produce antibodies that recognize the two antigens.
B. B cells carrying receptors for Antigen 1 produce antibodies that recognize Antigen 1, while different B cells carrying receptors for Antigen 2 produce antibodies that recognize Antigen 2.
