Which cells are primarily responsible for immune defense?

Which cells are primarily responsible for immune defense?

• A. Platelets
• B. White Blood Cells
• C. Red Blood Cells
• D. Plasma

Answer: (B)

White blood cells, or leukocytes, are the study’s focus when asking which cells defend against invaders. They circulate through blood and tissues and carry out immune tasks: phagocytes like neutrophils and macrophages ingest pathogens, while lymphocytes such as B cells and T cells coordinate and execute specific immune responses. Platelets mainly guard against bleeding by forming clots and can modulate inflammation, but their primary role isn’t defending against pathogens. Red blood cells carry oxygen and don’t participate in immune recognition. Plasma is the liquid component that contains proteins, including antibodies, but it isn’t a cell itself.

White blood cells, or leukocytes, are the study’s focus when asking which cells defend against invaders. They circulate through blood and tissues and carry out immune tasks: phagocytes like neutrophils and macrophages ingest pathogens, while lymphocytes such as B cells and T cells coordinate and execute specific immune responses. Platelets mainly guard against bleeding by forming clots and can modulate inflammation, but their primary role isn’t defending against pathogens. Red blood cells carry oxygen and don’t participate in immune recognition. Plasma is the liquid component that contains proteins, including antibodies, but it isn’t a cell itself.