Final answer:
T-lymphocytes in the thymus gland are protected from antigens by the blood-thymus barrier, a structure that isolates the developing T cells from potential antigen exposure during their maturation process.
Step-by-step explanation:
The T-lymphocytes in the thymus gland do not participate in the immune response and are protected from antigens by the blood-thymus barrier.
The thymus gland is a primary lymphoid organ where T lymphocytes, or T cells, mature. During their development, T cells undergo a selection process within the thymus to ensure that they can recognize foreign antigens presented by the body's cells while remaining tolerant to self-antigens. The thymus provides a safeguarded environment where this maturation and selection process occurs, isolated from potential exposure to antigens. This is largely possible thanks to the blood-thymus barrier, which prevents antigens from entering the thymic cortex where immature T cells reside.