BIO 447 Lecture Notes - Lecture 8: Lysosome, Phagolysosome, Pseudopodia
Document Summary
Pluripotent stem cell divides to replace itself generates stem cell in either lymphoid or myeloid series. Myeloid stem cell = source for all myelocytic white cells, pmns, monocytes & activated differentiated product cells, macrophages: also generates rbc lineage and megacaryocytes. Division and differentiation into a particular lineage is determined by: identity, concentration, and time of exposure to cytokine signaling molecules. Mononuclear cells: granulocyte-monocyte progenitor cells differentiate into promonocytes, promonocytes leave bone marrow and enter blood, circulate and differentiate into mature monocytes. Increase in number/complexity: enlarge 5-10x, acquires increased phagocytic ability, produces higher levels of hydrolytic enzymes, secrete soluble factors, migrate into tissues differentiate into specific tissue macrophages. Normally in resting state activated by variety of stimuli in course of immune response. Activated by phagocytosis of antigens: enhanced activation by cytokines secreted by activated th cells, mediators of inflammatory response, bacterial cell wall components. Phagocytosis: antibodies and complement proteins function as opsonins molecules that bind to antigen/macrophages to enhance phagocytosis.
