What is the primary role of the GALT? O GALT is in place to filter and trap blood-borne pathogens. O GALT is in place to distinguish self- from nonself-antigens thereby preventing autoimmune disease. O GALT, present in certain regions of the gastrointestinal tract, defends underlying tissue from potential pathogens that may be present in the gastrointestinal lumen. O GALT is in place to produce antibodies against potential pathogens that interface with the membranes.