A 28-year-old woman with HIV infection (CD4 count 150 cells/μL) develops recurrent painful oral ulcers and is found to have esophageal ulcers on endoscopy. She is already on acyclovir but continues to worsen. A viral culture grows a thymidine kinase-deficient mutant. Which of the following mechanisms best explains the clinical failure?
- A)The virus is producing increased levels of viral glycoproteins
- B)The drug failed to cross the blood-brain barrier
- C)The patient has developed neutralizing antibodies to herpes simplex virus
- D)The virus has developed altered DNA polymerase with reduced drug binding
- E)The virus cannot phosphorylate acyclovir, preventing its incorporation into viral DNAGABARITO
Explicação
Thymidine kinase (TK)-deficient HSV mutants cause acyclovir resistance. Acyclovir requires viral TK to be phosphorylated into its active form; without TK, the drug cannot be activated and therefore cannot be incorporated into viral DNA by viral DNA polymerase. Ver explicação completa e trilha adaptativa →