A 2-year-old boy with functional asplenia secondary to sickle cell disease (hemoglobin S on electrophoresis) presents for preventive vaccination against encapsulated bacteria. Vital signs are stable: BP 95/60, HR 110, RR 24, Temp 37.2°C, SpO2 98% on room air. He has no active infection and takes hydroxyurea daily. His pediatrician selects a conjugate vaccine formulation rather than a pure polysaccharide vaccine to enhance immunogenicity. Which mechanism best explains this advantage?
- A)The conjugate vaccine bypasses antigen presentation and directly activates cytotoxic T cells
- B)The conjugate vaccine works by passive transfer of preformed antibodies
- C)The conjugate vaccine stimulates only innate immunity and avoids memory formation
- D)The conjugate vaccine prevents antigenic drift in the pathogen
- E)Protein conjugation converts the response into a T cell dependent processGABARITO
Explicação
Pure polysaccharide antigens are T cell independent and generate relatively weak memory, especially in young children. Conjugating the polysaccharide to a protein carrier recruits T helper cells and produces stronger class switching and immunologic memory. Ver explicação completa e trilha adaptativa →