In immunology, immunocompetence is the ability of the body to produce a normal immune response following exposure to an antigen.
Immunocompetence is the opposite of immunodeficiency (also known as immuno-incompetence or being immuno-compromised).
In reference to lymphocytes, immunocompetence means that a B cell or T cell is mature and can recognize antigens and allow a person to mount an immune response.
In order for lymphocytes such as T cells to become immunocompetent, which refers to the ability of lymphocyte cell receptors to recognize MHC molecules, they must undergo positive selection.
[1] Adaptive immunocompetence is regulated by growth hormone (GH), prolactin (PRL), and vasopressin (VP) – hormones secreted by the pituitary gland.