Which of the following cell types is primarily involved in the adaptive immune response?

B cells play a crucial role in the adaptive immune response, which is characterized by its ability to specifically recognize and remember pathogens. These cells are a type of lymphocyte that can differentiate into plasma cells that produce antibodies tailored to specific antigens. When B cells encounter an antigen, they become activated and proliferate, leading to the production of antibodies that bind to the antigen, marking it for destruction and facilitating its elimination by other immune cells. This process allows the immune system to remember previous infections, enabling a faster and more effective response upon subsequent exposures to the same pathogen.

In contrast, macrophages, natural killer cells, and neutrophils are primarily involved in the innate immune response, which provides a non-specific defense against pathogens. They do not possess the same level of specificity or memory that B cells do, distinguishing them functionally within the immune system.