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Melissa, an otherwise healthy 22-year-old woman, is brought to the emergency room by her concerned boyfriend. She complains of a sudden onset of high fever, vomiting, diarrhea, and muscle aches. In her initial interview, she tells the attending physician that she is on hormonal birth control and also is two days into the menstruation portion of her cycle. She is on no other medications and is not abusing any drugs or alcohol. She is not a smoker. She is not diabetic and does not currently have an infection of any kind to her knowledge.
While waiting in the emergency room, Melissa’s blood pressure begins to drop dramatically and her mental state deteriorates to general confusion. The physician believes she is likely suffering from toxic shock syndrome (TSS) . TSS is caused by the toxin TSST-1, a superantigen associated with Staphylococcus aureus , and improper tampon use is a common cause of infections leading to TSS. The superantigen inappropriately stimulates widespread T cell activation and excessive cytokine release, resulting in a massive and systemic inflammatory response that can be fatal.
Vaginal or cervical swabs may be taken to confirm the presence of the microbe, but these tests are not critical to perform based on Melissa’s symptoms and medical history. The physician prescribes rehydration, supportive therapy, and antibiotics to stem the bacterial infection. She also prescribes drugs to increase Melissa’s blood pressure. Melissa spends three days in the hospital undergoing treatment; in addition, her kidney function is monitored because of the high risk of kidney failure associated with TSS. After 72 hours, Melissa is well enough to be discharged to continue her recovery at home.
Olivia’s swollen lymph nodes, abdomen, and spleen suggest a strong immune response to a systemic infection in progress. In addition, little Olivia is reluctant to turn her head and appears to be experiencing severe neck pain. The physician orders a complete blood count, blood culture, and lumbar puncture. The cerebrospinal fluid (CSF) obtained appears cloudy and is further evaluated by Gram stain assessment and culturing for potential bacterial pathogens. The complete blood count indicates elevated numbers of white blood cells in Olivia’s bloodstream. The white blood cell increases are recorded at 28.5 K/µL (normal range: 6.0–17.5 K/µL). The neutrophil percentage was recorded as 60% (normal range: 23–45%). Glucose levels in the CSF were registered at 30 mg/100 mL (normal range: 50–80 mg/100 mL). The WBC count in the CSF was 1,163/mm 3 (normal range: 5–20/mm 3 ).
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A ________ T cell will become activated by presentation of foreign antigen associated with an MHC I molecule.
cytotoxic
A ________ T cell will become activated by presentation of foreign antigen in association with an MHC II molecule.
helper
A TCR is a protein dimer embedded in the plasma membrane of a T cell. The ________ region of each of the two protein chains is what gives it the capability to bind to a presented antigen.
variable
Peripheral tolerance mechanisms function on T cells after they mature and exit the ________.
thymus
Both ________ and effector T cells are produced during differentiation of activated T cells.
memory
What is the basic difference in effector function between helper and cytotoxic T cells?
What necessary interactions are required for activation of helper T cells and activation/effector function of cytotoxic T cells?
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