Which of the following vaccines is recommended for healthcare workers to protect against hepatitis B?

Explanation: Vaccinations are made from either weakened or killed pathogens or parts of pathogens, which cannot cause the disease they are meant to protect against. However, they stimulate the body's immune system to produce a protective response, providing immunity against the specific disease.

Correct answer: C

A.B cells are part of the adaptive immune system and are responsible for antibody-mediated immunity. They do not directly attack and kill infected cells. Instead, B cells produce antibodies that can recognize and neutralize pathogens or foreign substances.

b. B cells are involved in antibody-mediated immunity, not cell-mediated immunity. They produce antibodies that circulate in the bloodstream and bind to antigens on pathogens, marking them for destruction by other immune cells.

c. B cells are crucial for recognizing "foreign" molecules (antigens) on pathogens and producing antibodies that can bind to those antigens. Macrophages engulf pathogens and present fragments (antigens) of them on their surface, allowing B cells to identify and target the specific pathogen.

d. Phagocytosis of pathogens is mainly carried out by macrophages and neutrophils, not B cells.