cells of immune system Flashcards
cells of immune system
lympocytes + macrophages
lymphocytes
B lymphocytes, T lymphocytes
originate from hemocytoblasts in red bone marrow, are identical at first, become B or T depending on location of immunocompetence
once lymphocyte is immunocompetent it reacts to one distinct antigen only bc all antigen receptors on its surface are identical
types of T lymphocytes
helper T cells, killer T cells, supressor T cells
become immunocompetent in thymus, non-antibody producing
carry out cell-mediated direct immunity + circulate continously throughout body , increasing change of coming into contact with antigens
B lymphocytes
become immunocompetent in bone marrow, produce antibodies,
carry out humoral indirect immunity
immunocompetence of T cells
maturation process of 2-3 days in thymus by thymic hormones (thymosin+)
immature lymphoctes divide fast and numbers increase but only T cells with sharpest idenfication of antigens survive, others are weeded out + destroyed
after IM, move to lymph nodes + spleen, encounters w/ antigens occur + become fully differentiated after coming into contact with antigens
immunocompetence of B cells
similar process in bone marrow, but little is knonw about factors that regulate it
after IM, move to lymph nodes + spleen, encounters w/ antigens occur + become fully differentiated after coming into contact with antigens
immunocompetency?
lymphocytes become immunocompetent before meeting antigens they attack
so genes, not antigens determine specific immunocompetency
bc of this only some antigens every actually invade the body + only some immunocompetent lymphocytes will ever be mobilized
macrophages
from monocyttes
in NSDS engulf foreign particles
act as antigen presenters (small fragments) to T cells
usually fixed in lymphoid organs
killer macrophages
activated T cells release chemicals that cause macrophages to become insatiable phagocytes
monokines
cytokine proteins important in IR secreted by macrophages+ monocytes
cytokines
diverse + potent chemical messengers secreted by immune cells
encourage cell growth, promote cell activation, direct cellular traffic, destroy targer cancer cells
lymphokines
cytokines secreted by Bcells + T cells
interleukins
cytokines that serve as messengers between different leukocytes
chemokines
cytokines released at site of injury/infection to attract specific cell types for repair
