Exam 3: Innate Immunity

A 4-year-old girl stepped on a rusty nail in her backyard.Two days later,she is taken to the pediatrician because her heel is painful,red,and swollen and is warm to the touch.All of the following are mechanisms of innate immunity that may be protecting the patient against pathogenic microbes in the heel wound EXCEPT:

Which one of the following comparisons between neutrophils and macrophages is true?

Toll-like receptors (TLRs)are a family of homologous receptors expressed on many cell types and are involved in innate immune responses.Ten different mammalian TLRs have been identified,and several ligands for many of these receptors are known.Which of the following is a TLR ligand?

Which one of the following statements about inhibitory receptors on natural killer (NK)cells is true?

A 3-year-old boy,who is small for his age,has a history of pyogenic (pus-producing)infections and cutaneous skin abscesses.Physical examination is remarkable for high fever,enlarged liver and spleen,and swollen cervical lymph nodes.A culture from an abscess on his arm reveals Staphylococcus aureus,a gram-positive bacteria that is also catalase-positive.Immunoglobulin and complement levels are normal.Results of the nitroblue tetrazolium test are consistent with a diagnosis of chronic granulomatous disease (CGD).The boy's immunodeficiency involves impaired generation of which of the following?

A 4-year-old-girl sees her physician because of a severe necrotizing,oropharyngeal herpes simplex viral (HSV)infection.She has a past medical history of cytomegalovirus (CMV)pneumonitis and cutaneous HSV infection.Phenotypic analysis of her blood cells shows an absence of CD56⁺ and CD16⁺ cells.There are normal numbers of CD4⁺ and CD8⁺ cells in the blood,and serum antibody titers are normal.The patient's CD8⁺ T cells were able to kill virally infected target cells in vitro.Which of the following is NOT characteristic of this girl's immunodeficiency disease?

Which of the following is a receptor on macrophages that is specific for a structure produced by bacteria but not by mammalian cells?

A 67-year-old homeless man is brought to the emergency department after being found behind a neighborhood bar in freezing weather.On arrival,he has a shaking chill,fever,and cough productive of blood-tinged sputum.A chest radiograph shows lobar consolidations consistent with bacterial pneumonia.Blood cultures are positive for Streptococcus pneumoniae.Which of the following molecular patterns recognized by Toll-like receptors expressed on the surface of this patient's phagocytes is important for activating his innate immune system against this gram-positive bacterial infection?

Which of the following comparisons of the innate and adaptive immune systems is FALSE?

A 43-year-old man with a history of kidney transplantation is on immunosuppressive drugs.He presents to the emergency department 84 days after transplantation with a slight fever,accompanied by violent shaking chills,rapid heart rate,and dangerously low blood pressure.Blood cultures are positive for gram-negative bacteria,including Klebsiella and Pseudomonas.Although the patient was initially alert and responsive to fluids and antibiotic therapy,his condition rapidly deteriorates into disseminated intravascular coagulation (DIC),hypoglycemia,and cardiovascular failure.Which of the following is an essential mediator of this patient's condition?

The signaling pathways triggered by Toll-like receptors typically result in activation of which of the following pairs of transcription factors?

All of the following molecules are opsonins that facilitate efficient phagocytosis of microbes by neutrophils and macrophages EXCEPT:

Which of the following is an example of how the innate immune response stimulates or modifies adaptive immunity?

Toll-like receptors and other receptors are potent activators of various components of the innate immune system.All of the following proteins are expressed in response to signaling by these receptors EXCEPT:

Complement activation in the innate immune system can be initiated in the absence of antibody.Which of the following molecular components of the complement system is involved in initiation of antibody-independent complement activation?

Which of the following statements about the innate immune system is NOT true?

Macrophages and neutrophils express several enzymes that are involved in biochemical mechanisms that kill ingested microbes.Which of the following is NOT an enzyme expressed by these cells?