The immune response following vaccination against a virus can be evaluated using three measurements: 1 the concentration of anti-virus antibody in the blood 2 the time taken for the antibody concentration to rise significantly after a booster vaccination 3 the number of virus-specific lymphocytes per $\text{cm}^3$ blood. What does this indicate about an individual’s immunity when the values for 1, 2 and 3 are all low ten years after vaccination?
- Aactive immunity due to the presence of memory cells
- Blow immunity due to the absence of antibodies
- Clow immunity due to the absence of memory cells
- Dpassive immunity due to the presence of antibodies