Final answer:
The lymphocytes described are Natural killer (NK) cells, which are large, granular, non-T, non-B cells with less prominent cytoplasmic granules than granulocytes and are involved in nonspecific immunity.
Step-by-step explanation:
The type of lymphocytes that are often described as large, granular, non-T, non-B lymphocytes, and contain less prominent cytoplasmic granules compared to granulocytes like basophils, eosinophils, and neutrophils, are Natural killer (NK) cells. Unlike granulocytes, NK cells are a type of agranocyte.
They play a critical role in the immune system by attacking a variety of infectious microbes and certain tumor cells without the need for prior exposure or immunity, providing a generalized, nonspecific immune response. This is in contrast to the B and T cells, which are responsible for adaptive immunity and have more prominent roles in specific immune responses.
Moreover, NK cells are among the larger lymphocytes and capable of recognizing cells without "self" proteins or with abnormal markers.