Which type of leukocyte is primarily responsible for the production of antibodies?

B lymphocytes, also known as B cells, are the type of leukocyte primarily responsible for the production of antibodies. When B cells encounter an antigen, they can differentiate into plasma cells, which are specialized for secreting antibodies that specifically target that antigen. This function is central to the adaptive immune response, providing long-lasting immunity and helping to neutralize pathogens.

The other types of leukocytes play different roles in the immune system. T lymphocytes are mainly involved in cell-mediated immunity, helping to recognize and destroy infected or cancerous cells, but they do not produce antibodies. Natural killer cells have a role in the innate immune response by targeting virally infected cells and tumor cells, without the need for prior sensitization to an antigen. Neutrophils are primarily responsible for phagocytosis and the immediate response to infection, particularly bacterial infections, but they do not produce antibodies either. Thus, B lymphocytes are uniquely specialized for antibody production, which is why they are the correct choice in this context.