Hematopoiesis – the formation and development of red and white blood cells.

Hematopoietic stem cells (HSC) – the cell type from which all lineages of blood cells arise.

Cells/Organs of the Immune System

Cells of the Immune SystemLeukocytes – White blood cells

Myelocytes –macrophage, neutrophil, eosinophil,basophil

Leukocytes – B, T and NK cells

From Larsson and Karlsson (2005)

Cells of the Immune System

Larsson and Karlsson (2005)

Homeostasis - The ability or tendency of an organism or cell to maintain internal equilibrium by adjusting its physiological processes.

Cells of the Immune System

Cells of the Immune SystemExamples of apoptosis

LM

SEM

Myeloid cells

Dendritic cell

Mononuclear phagocytes–Endocytosis takes material into a cell within vesicles that bud inward from the plasma membrane.

Mononuclear phagocytes

Granulocytic cellsNeutrophil

Lymphocytes:

T cellsB cells Natural killer cells

Cells of the Immune System

Lymphocyte fate following antigen activation:

Cells of the Immune System

Recall:Jerne, Talmadge & Burnet – clonal selection theory

B lymphocytes (B cells)

T lymphocytes (T cells)

T reg cell

•Natural killer cells – distinct from T and B cells due to lack of an antigen binding receptor, similar in function to TC cells.

NK Cells

Dendritic cells