A 5-month-old infant boy has repeated chest infections. Laboratory investigations reveal defective phagocytic function. Which is the defective cell in this case?

A 44 year old Egyptian journalist returns from a visit to Sudan. He develops irregular episodes of fever and chills. He attends to hospital and a blood film is done. What is the most likely finding in his blood film?

A 6-year-old boy received a Measles– Mumps- Rubella vaccine (MMR) at the age of 15 months. She is exposed to a colleague with measles but does not develop measles. Which property of the adaptive immune system best describes why she does not contract measles