1. Lymphocytes: These are the primary cells of the adaptive immune system, responsible for recognizing specific antigens and mounting targeted immune responses. Lymphocytes include:

* T cells: Mature in the thymus and are responsible for cell-mediated immunity. They directly attack infected cells or activate other immune cells.

* B cells: Mature in the bone marrow and are responsible for humoral immunity. They produce antibodies that bind to antigens and neutralize them.

2. Antigen-presenting cells (APCs): These cells are responsible for capturing and presenting antigens to lymphocytes, initiating the adaptive immune response. APCs include:

* Macrophages: Phagocytize pathogens and present antigens to T cells.

* Dendritic cells: Specialized antigen-presenting cells found in tissues and lymph nodes. They capture and present antigens to naive T cells, initiating the adaptive immune response.

While there are other cells that play important roles in immunity, such as NK cells and neutrophils, lymphocytes and antigen-presenting cells are considered the main immunocompetent cells due to their central role in recognizing and eliminating specific pathogens.