Final answer:
The statement is True; circulating lymphocytes do encounter lymph-borne pathogens in the lymph nodes. These nodes act as filters and house cells that help identify and eliminate pathogens. B and T lymphocytes then activate immune responses accordingly.
Step-by-step explanation:
The statement that circulating lymphocytes encounter lymph-borne pathogens in draining lymph nodes is True. On maturation, T and B lymphocytes, which are critical components of the immune response, circulate throughout the body. The lymph nodes, which are strategically located throughout the body, act as filters for the lymph as it drains from tissues. These lymph nodes house large populations of lymphocytes, dendritic cells, and macrophages which assist in the immune response.
As part of this system, lymph transports antigens it collects from the tissues to the lymph nodes. Within these nodes, antigen-presenting cells (APCs) capture, process, and present these antigens to the nearby circulating lymphocytes, notifying them of potential pathogens that need to be addressed. Thereby, B cells may get activated and produce antibodies as part of the humoral immune response, while T cells can stimulate cell-mediated immune responses, leading to the elimination of pathogens.