what is immunology and immune cell ?

Immunology is a branch of biology that covers the study of immune systems in all organisms. It involves studying the physiological functioning of the immune system in states of both health and diseases; malfunctions of the immune system in immunological disorders; the physical, chemical, and physiological characteristics of the components of the immune system in vitro, in situ, and in vivo.

An immune cell, also known as a leukocyte or white blood cell, is a cell that functions in the immune system to defend our bodies against harmful pathogens. There are several types of immune cells, including T cells, B cells, and phagocytes, each with a unique role in the immune response. T cells are responsible for cell-mediated immunity, B cells for humoral immunity (antibody production), and phagocytes for engulfing and destroying pathogens.