Introduction to Immune Cell Lineages and Development

A set of vocabulary flashcards covering the development, classification, and function of innate and adaptive immune system cells based on their stem cell lineages.

Hematopoietic Stem Cells

Immature, undifferentiated precursor cells produced in the bone marrow that give rise to erythrocytes, platelets, and leukocytes.

Common Myeloid Progenitor Cells

Stem cell derivatives that give rise to granulocytes and monocytes, playing an important role in the innate immune response.

Common Lymphoid Progenitor Cells

Stem cell derivatives that turn into natural killer (NK) cells, B cells, and T cells.

Neutrophils

The most abundant white blood cells and first responders following injury; polymorphonuclear granulocytes that track and phagocytose pathogens.

Polymorphonuclear Leukocyte (PMN)

A term commonly used to refer to neutrophils due to their characteristic multilobed nucleus.

Eosinophils

Tissue-residing granulocytes with a bilobate nucleus that pick up eosin dye, defend against parasites like helminths, and participate in allergic reactions.

Basophils

Granulocytes that pick up basic purply-blue dye and are involved in allergic reactions, particularly chronic conditions such as asthma.

Mast Cells

Granulocytes that mature in the blood, take up permanent residence in tissues like skin and mucosa, and release histamine in response to allergens.

Granulocytes

A group of immune cells—specifically neutrophils, eosinophils, basophils, and mast cells—that develop observable granules during maturation.

Agranulocytes

Leukocytes that lack observable granules, encompassing all immune cells other than neutrophils, eosinophils, basophils, and mast cells.

Monocytes

Innate immune cells that circulate in the blood before migrating into semisolid tissues to differentiate into macrophages or dendritic cells.

Macrophages

Phagocytic innate immune cells derived from monocytes in body tissues that digest pathogens and communicate with other cells to signal infection.

Dendritic Cells

Mature innate immune cells derived from monocytes that reside in environment-facing tissues, ingest pathogens, and present antigens to activate the adaptive immune system.

Natural Killer (NK) Cells

The only innate immune cells of the lymphoid lineage, which induce apoptosis in abnormal cells such as those infected by a virus.

B Cells

Adaptive lymphocytes that mature in the bone marrow and remain naive until exposed to a pathogen, after which they differentiate into plasma cells or memory B cells.

Plasma Cells

Differentiated B cells that function as antibody factories, pumping out large amounts of specific antibodies.

Memory B Cells

Differentiated B cells that retain information about pathogen exposures to mount a faster immune response upon re-encountering the pathogen.

T Cells

Adaptive lymphocytes produced in the bone marrow that migrate to mature in the thymus before differentiating into distinct subtypes.

Cytotoxic T Cells (CD8+ T Cells)

A major T cell subtype with armor-like CD8 markers that destroys abnormal, damaged, virus-infected, or cancerous body cells.

Helper T Cells (CD4+ T Cells)

A major T cell subtype with CD4 markers that coordinates the immune response by liaising between B cells, T cells, and innate immune cells.