What does a macrophages do?

A Macrophage is a white blood cell, produced by Monocytes. Monocytes and Macrophages are both Phagocytes. These work as a part of the human immune system. They act in non-specific "innate" immunity...

Macrophages are phagocytes, acting in both non-specific defense as well as to help initiate specific defense mechanisms of vertebrate animals. Their role is to phagocytose (engulf and then digest)...

- As white blood cells their job is to eat/consume, or engulf/digest cellular debris and pathogens. Which then stimulates lymphocytes and other immune cells to respond to the pathogen.

Macrophages act as phagocytes (engulfing antigens) and digest them for specific defense of immune system to detect. They are non-specific, therefore, they just digest and excrete antigens.

Murine means "of, related to, or affecting rodents of the family Muridae," like mice. Murine macrophages are simply macrophages of these types of animals.