Microbiology: chapter 14

A vaccine additive which enhances the body's natural immune response is called a(n)

adjuvant

Agglutination tests make use of the fact that

antibodies have two antigen-binding sites and will cause clumping when bound to antigen.

Live attenuated vaccines

are the closest to the actual infectious agent encountered in nature and stimulate potent immune responses to multiple antigens on the pathogen.

Your patient presents with sudden onset of fever, chills, fatigue, and cough which began yesterday. Based on the patient's clinical manifestations, you decide to perform a flu test using an enzyme-linked immunosorbent assay (ELISA). Which type of ELISA technique would be most appropriate to use given the patient's stage of disease?

A sandwich ELISA should be used since antibody production would not occur until later during the infection process.

During an agglutination reaction to determine blood type, the patient's blood agglutinated when anti-A, anti-B, or anti-D antibodies were added. What is the correct blood type designation?

AB+

While performing an ELISA, a lab technician fails to rinse away unbound detection antibody from the wells before adding the substrate for the reporter enzyme. What is the likely outcome of this error?

All wells, including controls, will indicate a positive result.

Which type of vaccine could possibly cause a person to develop the disease?

Attenuated live vaccine

How does immunofluorescence microscopy detect rabies in brain tissue of an infected animal?

Fluorescent-tagged antibodies bind to rabies antigen in the tissue and are visible in a specialized microscope.

Advantages of the interferon-gamma release assay (IGRA) over the traditional TB skin test include all of the following except

IGRA only detects active TB infections.

Both the Moderna and Pfizer COVID-19 vaccine formulations are examples of mRNA vaccines whereas the Johnson & Johnson/Janssen COVID-19 vaccine is a vector vaccine. Which of the following statements accurately describes how the mRNA and vector COVID-10 vaccine preparations are similar?

In both the mRNA and vector COVID-19 vaccine preparations, the patient's cells temporarily make the target protein.

A concerned mother is apprehensive about giving her 2-month old daughter the DTaP vaccine. The DTaP vaccine ingredients include an aluminum adjuvant, residual formaldehyde, and a combination of three different toxoids (diphtheria toxoid, tetanus toxoid, and inactivated pertussis toxin). Are any of these components concerning for the young patient?

None of the ingredients listed are concerning; this vaccine is safe to administer to the young patient.

Individuals infected with the RNA virus, human immunodeficiency virus (HIV), often require extensive, combination antiretroviral therapies. To check the effectiveness of new HIV drug cocktails, viral RNA levels can be measured over time in patient samples. Which of the following tests could be used to detect viral RNA levels within patient samples?

Reverse transcription-polymerase chain reaction (RT-PCR)

The Hepatitis B vaccine is which type of vaccine?

Subunit vaccine

Which of the following is needed to perform a polymerase chain reaction?

Taq polymerase

There are two major categories of COVID-19 tests: antigen tests and nucleic acid amplification tests (NAATs). The antigen tests and NAATs have comparable specificity, but the NAATs are more sensitive than the antigen-based tests. Based on this information, how would you expect the number of false-positives and false-negatives to compare between these two types of COVID-19 tests?

The antigen tests will have a greater number of false-negatives and a similar number of false-positives compared to the NAATs.

Several flu vaccine options exist including a live, attenuated nasal spray vaccine and intramuscular, inactivated vaccines. The live, attenuated flu spray is not recommended for immunocompromised individuals. Why might the intramuscular, inactivated flu vaccines be preferred over the live, attenuated flu spray for immunocompromised individuals?

The live, attenuated flu spray contains an infectious, weakened virus that could cause disease in an immunocompromised host.

Which of the following statements concerning the early history of vaccinations is true?

The practice of variolation involved blowing a powder made of dried scabs of smallpox lesions into a healthy individual's nose.

Which of the following occurs when a sample is first placed in a thermocycler for polymerase chain reaction (PCR)?

The sample is heated so that the double-stranded DNA molecule can be separated.

What is the hallmark of a conjugated vaccine?

These vaccines contain weakly antigenic elements plus a more potent antigenic protein.

Which of the following is not a drawback of live attenuated vaccines?

They are quickly cleared from the body, limiting antigen exposure.

Which of the following statements concerning vaccinations is correct?

Vaccinations stimulate immunological memory, allowing for a strong secondary response.

A 1998 study by Wakefield made the unfounded claim that the measles, mumps, and rubella (MMR) vaccine may trigger behavioral regression and developmental disorders such as autism in children. Which of the following is a valid problem with this study?

Wakefield was funded by lawyers who were suing the vaccine manufacturer and the parents of the children in the study were referred to Wakefield by the lawyers funding him.

Which of the following results would you expect from an interferon-gamma release assay from a patient suffering from an active tuberculosis infection?

You would expect T lymphocytes to release high levels of interferon gamma.

A major factor in the re-emergence of vaccine-preventable diseases in the early 21st century was

a flawed research study incorrectly linking vaccination to autism published in the late 1990s.

A DNA vaccine involves placing genes into a plasmid and introducing the plasmid into human cells. Human cells then transcribe and translate the genes to produce antigen, stimulating an immune response in the recipient. What is the source of the genes being introduced?

a pathogen

During production of an mRNA vaccine, lipid nanoparticles are used to encase mRNA. These lipid nanoparticles are readily uptaken into host cells after vaccine injection. Host cells then translate the viral mRNA to produce viral antigens, invoking an immune response. What is the original source of the mRNA in the vaccine?

a pathogenic virus or bacteria

Compared to a direct ELISA, a sandwich ELISA

can be designed to be read without a plate reader, making it suitable for home use.

There are 2 types of meningococcal vaccines currently available in the United States: MenACWY vaccines and MenB vaccines. The MenACWY vaccines contain the meningococcal A, C, W, and Y polysaccharides which are attached to a diphtheria toxoid protein carrier. The MenB vaccines contain the following recombinant proteins: Neisserial adhesin A (NadA) protein, Neisserial Heparin Binding Antigen (NHBA), and factor H binding protein (fHbp). A key difference between the MenACWY vaccines and the MenB vaccines is that only the MenACWY vaccines are:

conjugate vaccines

Reverse transcription PCR (RT-PCR) is used specifically to

detect the presence of RNA viruses.

Advantages that immunological diagnostics have over biochemical testing include all except

detection of an organism that has not been previously identified.

Genome mapping

documents the position of every nucleotide, provides a blueprint for the proteins and regulatory RNAs produced by a cell, and may reveal the presence of "pathogenicity islands" as well as information about genes for basic cellular functions.

The rapid "at home" COVID-19 tests work in the following way. A swab from the patient's nasal passages is applied to the strip. Liquid is added that will diffuse any protein toward a line that includes an antibody-linked enzyme that will bind to SARS-CoV2 protein. Over a few minutes, this line will turn pink if antigen from the virus is present. Based on this description, which best describes the type of diagnostic test being performed?

enzyme-linked immunosorbent assay (ELISA)

In a recombinant vector vaccine, genetic material from a pathogen is placed into a ________ and introduced to human cells.

harmless virus or bacteria

The influenza vaccine is an example of a(n)

inactivated killed vaccine.

In order to successfully and safely deliver a gene to a human cell, a virus vector must be

infectious but not pathogenic.

Recombinant DNA technologies are most often used for

producing large amounts of a particular protein quickly and easily.

The aspect of the immune response that vaccines are based on is

production of memory cells and high antibody titers from pathogen exposure.

Which enzyme is used to generate compatible sticky ends in order to join a desired gene to a plasmid vector in recombinant DNA techniques?

restriction enzymes

The CRISPR-Cas9 system uses all except which of the following?

reverse transcriptase enzyme

Which aspect of the polymerase chain reaction (PCR) is mismatched with its description?

template DNA: the DNA to be copied; must be present at a high concentration for the procedure to work

Plaque reduction neutralization tests (PRNT) are based on the fact that

the presence of antibodies in a patient's serum will prevent viral infection of cells in culture.

A drawback of all inactivated vaccines is that

they are quickly cleared from the body, limiting antigen exposure.

What is the function of boosters?

to maintain immunity

Conjugate vaccines which link the target antigen to a more immunogenic antigen are usually

vaccines against bacterial polysaccharide antigens.

DNA microarrays reveal

which genes are being expressed in a given cell.