What do macrophages do in response to an infection and where are they present?

They circulate in the blood, but when there's an infection they migrate into the tissues. they can be subdivided into M1 and M2 macrophages M2: remove debris and promote tissue repair M1: kill phagocytosed bacteria, produce ROS, nitric oxide and enzymes, attract neutrophils, NK cells and activated T cells by producing chemokines