The science behind white blood cells explains how the immune system identifies, attacks, and remembers pathogens. Leukocytes originate in bone marrow and circulate through blood and lymphatic tissue, differentiating into neutrophils, lymphocytes, monocytes, eosinophils, and basophils. Each type performs a specialized function, from phagocytosis to antibody production. When infection occurs, signaling molecules trigger rapid proliferation and targeted migration to affected sites. Antibiotics support this response by reducing bacterial load; in clinical supply chains, ceftriaxone injection wholesale availability is critical for timely treatment. Understanding white blood cell dynamics helps clinicians optimize therapy, manage resistance, and improve patient outcomes across infections globally.