White blood cells (leukocytes) are vital components of the immune system, protecting the body against infections and foreign invaders. The main types include neutrophils, which rapidly respond to bacterial infections; lymphocytes, such as B cells and T cells, which manage targeted immune responses; monocytes, which mature into macrophages to engulf pathogens; eosinophils, involved in allergic reactions and parasite defense; and basophils, which release histamine during inflammation. Understanding these cells is essential in clinical care, including antibiotic therapy decisions supplied through channels like a ceftriaxone injection wholesaler, ensuring effective treatment of bacterial infections that challenge the immune system.