AP BIOLOGY

Detailed explanation-1: -Immature dendritic cells resident in infected tissues take up pathogens and their antigens by macropinocytosis and receptor-mediated phagocytosis.

Detailed explanation-2: -Macrophages and neutrophils (phagocytes) are the front-line defenders in your body’s immune system. They seek out, ingest, and destroy pathogens and other debris through a process called phagocytosis.

Detailed explanation-3: -A macrophage is the first cell to recognize and engulf foreign substances (antigens). Macrophages break down these substances and present the smaller proteins to the T lymphocytes.

Detailed explanation-4: -The first line of immune defense against invading pathogens like bacteria are macrophages, immune cells that engulf every foreign object that crosses their way. After enclosing it in intracellular membrane vesicles, a process called phagocytosis, macrophages kill their prey with acid.

Detailed explanation-5: -It is clear that macrophages serve as antigen-presenting cells for a variety of specific immune responses and that many antigens are presented by macrophages to T lymphocytes in the context of the products of the I region of the major histocompatibility gene complex (MHC) of a species.