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Reference Guide

Permachart - Marketing Reference Guide: Antigen-Presenting Cell, Memory T Cell, Clonal Deletion

4 pages225 viewsFall 2015

Department
ANAT - Anatomy
Course Code
ANAT 14
Professor
All
Chapter
Permachart

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Immunology
Immunology
GENERAL I N F O R M ATION - AN OVERVIEW
• The immune system is a defense mechanism of the body
characterized by the recognition of nonself in the protection
of the body from microorganisms and other harmful
substances
• The two main components are innate (nonspecific)
immunity and adaptive (specific) immunity
• Innate immunity is a general natural defense against anything
recognized as nonself
• It is present (in normal individuals) at all times and triggered
as soon as the foreign agent presents itself
• Adaptive immunity is the response of lymphocytes to foreign
substances (called antigens, from antibody generating) and
includes development of immunological memory
• Adaptive immunity consists of two responses against foreign
antigen: the humoral response (defined by secretion of
antibody by B cells) and the cell-mediated response (which
involves the attacking and killing of infected somatic cells
directly by T cells)
INNATE (NONSPECIFIC) IMMUNITY
• Innate immunity has seven main protective mechanisms that
function without prior exposure to a harmful agent
TH E C EL L S
Dendritic Cells Antigen Presenting Cells (APCs) found in T cell area of lymphoid
tissues • Particularly important for initiation of the adaptive immune
response
Macrophages Phagocytic cells derived from
blood monocytes Contain
lysosomes, which digest
pathogens • Act as APCs,
alerting lymphocytes of specific
foreign antigens by displaying
pieces of partially digested antigen
on their surface • Express MHC I
and MHC II molecules
B Cells Lymphocytes that mature
in the bone marrow and
play a key role in humoral
immunity • After being
presented with a foreign
antigen, the B cell differentiates
into either antibody-secreting
plasma cells or memory B cells
to be activated when the same
antigen is encountered again
(secondary immune response)
Plasma Cells Cells that differentiate from
B cells and secrete
large amounts of antibodies
(up to 2000 per second)
• All cells in a clone of plasma
cells secrete identical antibodies
because they are descended
from the same B cell
T Cells Lymphocytes which mature
in the thymus and act in
humoral and cell-mediated
immunity • After being
presented with a foreign antigen,
T cells differentiate into effector
cells that are able to destroy
infected cells or activate other
cells of the immune system
Antimicrobial Such as interferon (inhibits viral replication) and
Substances complement proteins (promote bacterial
destruction and other effects of inflammation)
Fever Produced by endogenous pyrogens secreted by
leukocytes and other cells, and serves to intensify
the action of interferon, inhibit microbial growth,
and enhance tissue repair
Gastric Acid Destroys swallowed invaders
Inflammatory Mobilizes leukocytes to phagocytose invaders
Response
Intact Skin Prevents attachment of potential invaders
Mucous Traps bacteria and other foreign material
Natural Killer Destroy a variety of microbes and certain tumor
Cells cells through direct contact
CD4 T-cells Bear the CD4 marker
and respond to MHC II
molecules • There are
two types: Th1 cells
(inflammatory T cells)
that activate infected
macrophages to destroy
intracellular pathogens,
and Th2 cells (helper T
cells) that stimulate B
cells of the same
antigenic specificity to
differentiate into
antibody-secreting
plasma cells or memory
B cells
Cytotoxic T-cells Bear the CD8 marker
and respond to MHC I
molecules • Kill infected
cells either by releasing
perforin (a protein that
punches holes in
infected cells’
membranes) or binding
to a receptor on the
infected cell to initiate
apoptosis (cell suicide)
• Important in defense
against cytosolic
pathogens
Memory T-cells T cells that are produced
but not used in a first
immune response
• They circulate and are
ready to respond to
subsequent attacks by
the same type of invader
Suppressor T-cells Suppress the activity of
other T cells that are
capable of causing
tissue damage
IMMUNOLOGY • 1-55080-832-X 1© 1999-2012 Mindsource Technologies Inc.
2nd EDITION
w w w . p e r m a c h a r t s . c o m
TM
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