MMI Exam 1 TopHat Questions

A 45-year-old patient presents with cellulitis caused by Staphylococcus Aureus. Laboratory testing shows increased leukocytes. Which cell type is most likely the first to arrive at the site of infection?

Neutrophils

A patient develops urticaria and wheezing minutes after receiving a medication. Cross-linking of IgE antibodies on which cell type is primarily responsible for;e for release of histamine?

Basophils and mast cells

A patient has influenza. Which immune cell is primarily responsible for killing host cells infected with the virus in an antigen-specific manner?

CD8+ cytotoxic T lymphocyte

A child is born without a functional thymus. Which immune abnormality would most likely occur?

Impaired T-cell maturation

IgE-mediated histamine release occurs primarily from which of the following cells?

Basophils and mast cells

Generation of antigen-binding specificity in T and B lymphocytes occurs through which of the following mechanisms?

DNA rearrangement occurs before antigen exposure, creating diverse antigen receptors

What is meant by clonal selection?

Multiplication of antigen-specific lymphocytes

Which of the following correctly describes the primary site of hematopoiesis during fetal development and adulthood?

Fetal liver; adult red bone marrow

A macrophage located in the liver is most appropriately referred to by which of the following names?

Kupffer cell

A 25-year-old man undergoes an emergency splenectomy following a motor vehicle accident. During a follow-up visit, his healthcare provider explains that the removed organ played an important role in monitoring agents circulating in the bloodstream. Which of the following best describes a primary immune function of the spleen?

Filters antigens from the blood.

Which antibody region is primarily responsible for antigen recognition?

Variable regions of heavy and light chains

Which comparison best explains why both strike-targeting monoclonal antibodies and mRNA vaccination can reduce SARS-CoV-2 entry, while producing different types of immune protection?

Monoclonal antibodies provide spike-binding antibodies directly, whereas mRNA vaccination induces host cells and immune cells to generate antibodies and memory.

Which of the following immunoglobulins is found on epithelial surfaces and in respiratory and gastrointestinal tract secretions, and is the predominant antibody in saliva, tears, and breast milk?

IgA

Which immunoglobulin crosses the placenta?

IgG

Rheumatic fever after streptococcal infection is due to:

Antibody cross-reactivity with host tissues

Which enzyme initiates V(D)J recombination?

V(D)J recombinase

A patient develops antibodies after penicillin is linked to human serum albumin. Which interpretation best explains why free penicillin can later bind those antibodies but cannot independently induce the response?

Penicillin acts as a hapten whose immunogenicity depends on attachment to a protein carrier.

What defines a monoclonal antibody?

Binding a single epitope from one parent clone

A B cell changes from producing IgM to IgG after receiving helper T-cell cytokine signals. Which outcome best explains this change?

The antibody retains antigen specificity but gains the biological functions of IgG

Case: A 35-year-old patient with relapsed CD30-positive anapestic large cell lymphoma is receiving brentuximab vendotin. During a pharmacotherapy discussion, a PharmD student is asked why this medication is considered an antigen-drug conjugate (ADC) rather than a traditional antibody. Which component of brentuximab vedodin is primarily responsible for causing lymphoma cell death after the drug is internalized.

Monomethyl auristatin E (MMAE), which disrupts microtubule function

Which explanation best connects antigen recognition by a helper T cell with the action of ipilimumab in anti tumor immunity?

The TCR recognizes peptide-MHC II, CD4 stabilizes the interaction, CD3 transmits the signal, and ipilimumab releases an immune brake.

A researcher observes that a T-cell clone expands after antigen activation. Based on T-cell receptor biology, which outcome is expected regarding the clone’s antigen-binding affinity?

It remains unchanged because T cells lack somatic hypermutation

A 24-year-old patient develops influenza. Viral proteins synthesized inside infected respiratory epithelial cells are processed and presented to the immune system. Which pathway is primarily responsible for activating the T cells that eliminate the infected cells?

Endogenous peptide presentation on MHC I to CD8+ cells

A genetic defect prevents thymocytes from recognizing self-MHC molecules during development. What is the most likely result?

Failure of positive selection causing apoptosis

A patient receives a protein vaccine. Activated helper T cells subsequently stimulate B-cell proliferation, isotope switching, and plasma-cell formation. Which T-helper subset is primarily involved?

TH2 cells promoting humoral immunity

During a group discussion, one of your classmates asks why mature red blood cells do not present antigens on MHC class I molecules. What is the best explanation?

Red cells lack nuclei required for MHC expression.

An unrelated donor’s tissue is transplanted into a recipient. Which feature most strongly explains why the recipient may recognize the graft as foreign and reject it?

The donor and recipient may express different, co-dominantly expressed MHC alleles.

A virus-infected cell is processing an antigen for T-cell recognition. Which presentation pathway and peptide feature best match this situation?

MHC I presents an 8-10 amino-acid peptide to a CD8+ T cell.

A researcher studies immune responses to mycobacterium tuberculosis glycolipids. Which molecule presents these antigens to T cells?

CD1 molecule

A 22-year-old college student presents to the emergency department with acute-onset fever, hypotension, diffuse erythematous rash, nausea, and profuse vomiting several hours after consuming food at a campus event. Laboratory studies show elevated inflammatory markers but no evidence of a specific antigen-driven immune response. The infectious disease team suspects exposure to Staphylococcus Aureus enterotoxin B (SEB). which of the following best explains the mechanism responsible for this patient’s presentation?

The toxin binds directly to MHC II molecules and the VB region of T-cell receptors, causes polyclonal activation of a large number of T cells.

A pathogen enters the body before an adaptive immune response have been unregulated. Which defense system is best positioned to limit its entry and spread during this early period?

The innate immune system, through anatomical, physiologic, phagocytic/endocytic, and inflammatory barriers.

A patient develops bacteremia. Specialized liver macrophages remove many circulating bacteria from the bloodstream. Which macrophage subtype performs this role?

Kupffer cells

A macrophage detects lipopolysaccharide from a gram-negative bacterium through a receptor that recognizes conserved microbial patterns. Which response most directly follows this detection?

Cytokines initiate inflammation

A patient carries a mutation that prevents assembly of C5b-C9 complexes. Which complement function is most directly impaired?

Pathogen membrane lysis

A dendritic cell processes a viral protein after encountering an infected cell. The processed peptide is subsequently displayed on an MHC molecule. Which immune cell recognizes this antigen-MHC complex?

T cell through TCRs

A patient receiving monoclonal antibody therapy for lymphoma demonstrates significant tumor cell death. Laboratory analysis shows that the tumor cells are coated with antibodies and are subsequently recognized by NK cells. Which receptor on the NK cell mediates this process?

Fc receptor CD16

A patient develops a rash during infection. Which sequence best explains the immunologic events leading to rash formation?

Pathogen recognition → cytokine release → immune cell recruitment → tissue injury

A 54-year-old patient with advanced cirrhosis develops recurrent bacterial infections. The physician suspects impaired production of complement proteins. Which statement best explains this finding?

Most complement proteins are produced in the liver.

A patient develops a bloodstream infection and produces both IgM and IgG antibodies against the pathogen. The infectious disease physician explains that one antibody is particularly effective at activating complement. Which antibody is the strongest activator of the classical complement pathway?

IgM

A 32-year-old woman with paroxysmal nocturnal hemoglobinuria (PNH) is started on eculizumab therapy. The pharmacist explains that the medication works by inhibiting a key component of the complement cascade. Which complement protein is directly inhibited by eculizumab?

C5 complement protein.

A TH0 cell interacts with an APC through CD80-CD28 in a cytokine environment containing IL-2 and IFN-y. Which outcome is most likely?

It develops into TH1 and promotes cell-mediated immunity.

A hiker develops a pruritic vesicular rash 48 hours after poison ivy exposure. Which hypersensitivity reaction best explains this presentation?

Type IV delayed hypersensitivity

Why does a second exposure to the same allergen produce an immediate reaction after the initial exposure did not?

IgE formed during sensitization cross-links on mast cells, triggering degranulation.

An Rh-negative mother develops anti-Rh IgG antibodies during a second Rh-positive pregnancy. Which mechanism is primarily responsible for fetal injury?

Maternal IgG-mediated destruction of fetal RBCs

A 26-year-old graduate student receives a pneumococcal polysaccharide vaccine. Several months later, laboratory testing shows predominantly IgM antibodies with minimal immunologic memory. Which immunologic mechanism best explains this response?

T-cell independent B-cell activation

A patient receives an allogenic kidney transplant. Prior to transplantation, donor and recipient undergo extensive HLA testing. Which is the primary purpose of HLA matching?

Minimize graft rejection risk

A self-reactive T cell recognizes antigen on an APC in a peripheral tissue, but the local environment provides weak co-stimulation and inhibitory signals. What outcome best reflects peripheral tolerance?

The T cell becomes functionally inactive or undergoes deletion.

An auto reactive B cell encounters persistent self-antigen while its helper T cell recognizes antigen through the TCR, but CD28-mediated co-stimulation is blocked. Which outcome best explains how self-tolerance is maintained?

The B cell becomes functionally inactive because of inadequate help, which the T cell develops reduced IL-2 production and energy.

Why does HIV infection increase susceptibility to opportunistic infections and certain cancers as CD+ T helper cells decline?

It reduces activation of B cells, cytotoxic T cells, and macrophages.

A person previously treated with rattlesnake antivenin is bitten again several months later. Which management best reflects the expected immune response and protections from the earlier treatment?

The person requires repeat antivenin because prior treatment provided limited memory and short-term protection.

A monoclonal antibody is best described as recognizing?

A single epitope

A patient has lepromatous leprosy with poor bacterial control and widespread disease. Which immune profile best explains this outcome?

Predominant TH2 response

A patient experiences repeated influenza infections because viral surface proteins keep changing. Which immune evasion strategy is illustrated?

Antigenic variation

Flow cytometry is commonly used to monitor?

CD4 counts

Pokeweed mitogen activates?

B and T cells

A patient’s serum is tested against Treponema palladium fixed on a slide. After incubation, washing, and addition of fluorescent anti-human globulin, the bacteria emit fluorescence. What does this result indicate?

The patient has antibodies indicating syphilis

A patient develops fever, hypotension, diffuse erythema, and multi organ dysfunction after Staphylococcus aureus infection producing TSST-1. Which mechanism is responsible?

Superantigen-mediated T-cell activation

A virus-infected host cell displays viral peptide fragments on its surface. Which interaction best explains how the cellular immune response targets this cell?

CTLs recognize viral peptides presented by MHC class I and kill the infected cell.

A host encounters an intestinal parasitic worm that is too large for phagocytic engulfment. Which response best explains how the immune system limits the parasite?

Th2 cells promote IgE-associated mast-cell degranulation and eosinophil activation.

A bacterium has been engulfed by a phagocyte but remains inside to the lysosome’s toxic enzymes. Which evasion strategy best explains this survival?

Inhibiting fusion between the phagosome and lysosome.

A pregnant patient develops an infection after easting unpasteurized cheese, and fetal infection is a concern. Which organism-treatment pairing best fits this presentation?

Listeria monocytogenes— Ampicillin

A bacterium has a thin peptidoglycan layer, a periplasmic space, and an outer membrane containing LPS. Which outcome best follows from these features during gram staining?

It is gram-negative, loses crystal violet, and appears pink or red

Following a dental procedure, a patient with damaged heart valves develops endocarditis. Which organism group is most likely?

Viridans Streptococci

A man presents with urethritis and purulent discharge. Gram-negative coffee bean-shaped diplococci are seen. What is the organism?

N. Gonorrhoeae

A patient steps on a rusty nail and later develops muscle rigidity and lockjaw. Which organism is responsible?

C. tetani

If mucosal trapping and ciliary clearance are bypassed, which mechanism primarily helps maintain bacterial balance in the lower respiratory tract?

Macrophage and phagocyte activity

Which of the following FDA-approved therapeutic agents is made from purified human stool bacteria and is used to prevent recurrent Clorstridioides difficile infections in humans?

Vowst and REBOYTA

Which pairing correctly connects a bacterium, its own toxin effect, and an appropriate intervention?

Corynebacterium diphtheriae inhibits protein synthesis, causing tissue damage; antitoxin and toxoid vaccination are appropriate.

A 7-year-old child develops watery diarrhea, stomach cramps, nausea, and mild weight loss a few days after spending time at a community swimming pool. Several other swimmers report similar symptoms. The healthcare provider suspects an infection caused by an organism that is resistant to chlorine. Which pathogen is most likely cause?

Cryptosporidium parvum

A patient asks a pharmacist about products that support a healthy git microbiome. The pharmacist explains that one option contains substances that nourish beneficial bacteria, another contains live beneficial microorganisms, and a third contains non-living microorganisms or their components that provide health benefits. Which of the following correctly identifies these products?

Prebiotic= substances that nourish beneficial bacteria; Probiotic= live beneficial microorganisms; Postbiotic= Non-living microorganisms or their components

A virus carries an RNA genome encoding a polymerase and structural proteins but lacks genes for energy and protein-synthesis machinery. Which conclusion best explains its replication strategy?

It depends on host-cell metabolism and machinery for replication.

Which sequence best describes replication of an enveloped retrovirus after it enters a host cell?

Its genome is released into the cytoplasm, reverse-transcribed into DNA, integrated into the host genome, and progeny bud from the cell membrane.

A patient with suspected influenza requires direct viral RNA detection. Which test is best?

RT-PCR

A toddler presents with a barking cough and croup. Which virus is most likely?

Parainfluenza virus

What is the primary way that polio (poliomyelitis) spreads from one person to another?

Fecal-oral route

Which virus causes chickenpox (varicella) and can later reactivate to cause shingles?

Varicella-Zoster Virus (VZV)

What is the defining characteristic of a prion?

It s an infectious, misfiled protein that converts normal prion proteins into an abnormal form.

A patient develops acute hepatitis during a waterborne outbreak in an endemic region. Which virus and management best fit this presentation?

Hepatitis E; supportive care

A virus that binds CD4 cells through gp120?

HIV

A patient develops an aggressive malignancy of mature CD4+ T lymphocytes many years after infection, following a prolonged latent period. Which viral infection best explains this presentation?

HTLV infection, which can promote malignant T-cell transformation and ATLL

A patient develops a candida infection after prolonged antibacterial therapy and immunosuppressive treatment. Which combination best explains this increased risk?

Disrupted bacterial flora and impaired cell-mediated immunity

A fungus is observed as a filamentous form in the environment but as a yeast-like form in human tissue. How should it be classified?

A Dimorphic fungus

A fungal population undergoes fusion between compatible hyphae. Which sequence and outcome best describe this reproductive strategy?

Plasmogamy, karyogamy, and meiosis, producing genetically varied sexual pores.

A patient has general itching, burning, redness, and white discharge. Which interpretation best fits these findings and the recommended management?

A Candida albicans infection that may be sexually transmitted and treated with fluconazole, clotrimazole, or miconazole.

A 45-year-old construction worker from Arizona presents with fever, cough, fatigue, and a recent history of working in dusty environments. The pharmacist recognizes that certain fungal infections are associated with specific geographical regions. Which organism is most strongly associated with the Southwestern United States?

Coccidioides immitis

A 22-year-old college athlete presents to a community pharmacy complaining of itching, scaling, and peeling skin between his toes. He reports showering daily in a shared locker room after basketball practice. The pharmacist suspects a dermatophyte infection commonly known as “athlete’s foot.” Which fungus is most likely cause?

Trichophyton rubrum

A patient with a prior pulmonary cavity develops hemoptysis. Imaging reveals a fungal ball within the cavity. Which diagnosis is most likely?

Aspergilloma caused by Aspergillus species.

A 48-yar-old patient receiving chemotherapy for acute leukemia develops fever, cough, and progressive pulmonary infiltrates despite broad-spectrum antimicrobial therapy. Culture results eventually identify a filamentous fungus associated with mucormycosis. Which environmental source is most commonly associated with this organism?

Soil, plants, and decaying fruits

A drug is being selected to target a membrane component unique to fungi rather than the sterol found in human cell membranes. Which drug class and mechanism best fit this goal?

Polyenes bind to ergosterol and disrupt fungal membrane function.

A 58-year-old man presents for evaluation of chronic liver disease. During a nutrition assessment, he reports regularly consuming improperly stored peanuts obtained from local markets. The healthcare provider explains that certain fungal toxins found on peanuts are potent carcinogens that can damage the liver over time. Which organism is most commonly associated with production of aflatoxin B1?

Aspergillus Flavus

A school nurse discovers that several students have head lice after sharing hats during a field trip. The organisms are found attached to hair and feeding on the scalp. What type of parasite are the lice?

Ectoparasitic arthropods

A patient has watery diarrhea, and the laboratory needs to identify Cryptosporidium in a fecal specimen. Which diagnostic approach is most appropriate?

Apply the modified Kinyoun acid-fast stain to the specimen.

Which comparison best explains how host immunity differs across the parasites described?

Plasmodium spp. provoke antibodies, T cell, and IFN-gamma cell mediated immune responses, whereas Hookworms can provoke eosinophil, IgE, and Th2 associated response.

Which medication is commonly used to treat Amebiases?

Metronidazole for invasive amebic infections.

Infectious stage Giardia transmission?

Cyst

A patient develops cardiac and digestive problems after exposure to triatomine bugs and presents with swelling near one eye. Which diagnosis and causative organism best fit this presentation?

Chagas disease caused by Trypanosome Cruzi

A stool specimen from a patient with suspected taeniasis is sent to the laboratory. Microscopic examination confirms the diagnosis. Which life cycle stages are typically identified in feces?

Eggs and proglottids in stool

An 8-year-old child from a rural area presents with abdominal pain, nausea, and signs of malnutrition. Further evaluation reveals an intestinal obstruction caused by a heavy worm burden. Stool examination demonstrates oval eggs consistent with a roundworm infection. The healthcare provider prescribes albendazole. Which parasite is most likely responsible for this infection?

Ascaris lumbricoides

A public health nurse administers a malaria vaccine as part of a childhood immunization program in an endemic region. Against which malaria species are RTS,S/AS01 and R21/Matrix-M primarily designed to protect?

Plasmodium falciparum causing severe disease.

A traveler develops multiple inflamed foot lesions, ulceration, and difficulty walking; eggs are observed emerging from the skin lesions. Which diagnosis and treatment best fit this presentation?

Tungiasis; remove the lesions surgically.