What are immune cells?

Immune cells are specialized cells whose primary function is to carry out immune responses and protect the human body from infections. Immune cells mainly include lymphocytes, macrophages and their progeny, as well as other cells involved in immune responses. Lymphocytes originate from lymphocyte precursors (B cells and T cells) and their descendants; B cells produce antibodies, while T cells can directly kill infected cells. Macrophages eliminate various pathogens—including viruses, bacteria, and fungi—through multiple mechanisms. Additionally, other cells participate in immune responses, such as dendritic cells and meningococci, which can secrete specific cytokines to assist or suppress the activities of other immune cells. Through coordinated interactions, immune cells mount effective immune responses that protect the body against infection.