Which type of cells are primarily involved in the primary immune response?

The primary immune response is primarily mediated by B cells. During this initial phase of the immune response, B cells are activated when they encounter an antigen that matches their specific receptor. Upon activation, B cells differentiate into plasma cells that produce antibodies specifically tailored to that antigen. This process can take several days, but it is crucial for the body to mount an effective response against pathogens during the first encounter.

In contrast, T cells are more significant in the secondary immune response, where they quickly respond to previously encountered antigens. Memory cells, which are derived from B and T cells, are generated after the primary immune response and are responsible for providing long-lasting immunity. Neutrophils are important components of the innate immune system and act as one of the first responders to sites of infection, but they do not directly mediate the adaptive immune response.

Thus, B cells play the central role in initiating the primary immune response by recognizing specific antigens and producing antibodies, making them the correct answer.