Immunopathology 1 Flashcards
The body must defend itself against infections, organisms and maintain its identity by means of nonspecific defense mechanisms ( _______ ) and
specific defense mechanisms ( _______ )
resistance
immunity
The task of the immune system is the body’s ability to distinguish between
_______ substances (“___ ”) and _______ substances (“______”).
This system can be subdivided into two different families of cells,
the _____ and ______
autologous; self
exogenous; non-self
B and T lymphocytes.
The B cells are responsible for _____ immunity.
humoral
B cells
Their effector mechanism consists of the ______ they produce , which are supported by a ____________
antibodies
system of complements activated in a cascade.
B cells
Their effectiveness is attributable to the ______ they generate and to ______ among them
cytokines
killer cells
HYPERSENSITIVITY REACTIONS
Here the organism responds to _____ contact with _________ and to which it is ______
renewed
an antigen that it already knows
hypersensitive
Effectors and description of the hypersensitivity reactions
Type 1
Type 2
Type 3
Type 4
Immediate ; IgE
Cytotoxic ; IgG and IgM
Immune; IgG and IgM
Delayed; Tcells
AUTOIMMUNE DISEASES
In these disorders, the body _____________
Accordingly, autoreactive ______ or autoreactive ______ that attack autologous substrates are crucial elements in the pathogenesis of these disorders
violates the protection of its own identity and attacks itself.
antibodies; lymphocytes
IMMUNODEFICIENCY DISEASES
These disorders are attributable to a _________ response to various antigen stimuli.
deficient immune
In immunodeficiency diseases
Congenital B-cell defects are clinically conspicuous because of the ______________ that they involve.
In contrast, primary T-cell defects leave the patient unprotected against _____________
reduced resistance to bacterial infection
viruses and fungi.
IMMUNODEFICIENCY DISEASES
Patients with a combined B cell and T-cell deficiency are __________
poor candidates for survival.
Among the acquired immunodeficiency disorders, _______ due to ___________ of a plasma cell clone and ____ due to infection with the human immunodeficiency virus (HIV) warrant special mention.
gammopathy
neoplastic proliferation
AIDS
Innate immunity
It is the initial response by the body to eliminate microbes and prevent infection occurring ______ after exposure to an antigen
immediately or within several hours
Innate immune responses are as powerful as adaptive immune responses in combating infections
F
Innate immune responses are not as powerful as adaptive immune responses
Innate immune responses improve with repeated exposure to a given infection
T/F
F
Innate immune responses do not improve with repeated exposure to a given infection
Innate immunity
-is present after infection
-mounted in response to infection
- recognizes every possible antigen.
F. Before
F. Not
F. Doesn’t
Innate immunity
Designed to recognize ___________ molecules shared by groups of related microbes that are essential for the survival of those organisms but are not ___________.
pathogen-associated molecular patterns (PAMPS),
found in mammalian cells
PAMPs are not found on _________ alone but __________ hence, they are also called ________
pathogenic microbes
all microbes of the specific groups
microbe associated molecular patterns (MAMPs
Pathogen associated molecular patterns (PAMPs)
They include
____ from the gram-negative cell wall
____ and _____ from the gram-positive cell wall
the sugar ______
bacterial ______
______ from fungal cell walls
LPS; peptidoglycan and lipotechoic acids
mannose
flagellin
glucans
Pathogen associated molecular patterns (PAMPs)
They include
bacterial and viral _______________ motifs (found in many bacteria)
the amino acid _____found in bacterial proteins double-stranded and single-stranded RNA from viruses
unique molecules displayed on stressed, injured, infected, or transformed human cells may also stimulate _____, called ________________
unmethylated CpG DNA
N-formylmethionine
TLRs
danger associated molecular patterns.
Innate immunity
Examples of innate immunity include
anatomical _____
______ removal
_______ antagonism
________ receptors
___________ defense chemicals
the ______ pathways
____,_____,______
barriers; mechanical; bacterial
pattern-recognition
antigen-nonspecific
complement
phagocytosis
inflammation
fever
Innate immunity
The major cells involved in innate immunity include
phagocytic cells ( _____,_____ ,_____)
cells that release inflammatory mediators (_____,______,______)
______ cells
_______ cells
_______ cells
neutrophils, monocytes and macrophages
basophils, mast cells, and eosinophils
Natural killer
Mucosal epithelial ; Endothelial
The best defined pattern recognition receptors are the _______
Toll-like receptors (TLRs).
Cells of innate immunity
These cells express _______ receptors, cellular receptors that recognize ____.
pattern recognition
PAMPs
Innate and adaptive immunity:
complement activation
In innate immunity, the complement system is activated by binding to microbes using the ________ pathways.
alternative and lectin
In adaptive immunity, it is activated by binding to antibodies using the ______ pathway.
classical
Cells of the adaptive immunity system
______
______
______
_________
________
T lymphocytes
B lymphocytes
Macrophages
Antigen presenting cells e.g. dendritic cells.
NK cells
Neutrophils, basophils and eosinophils play a major role in defense systems and are directly involved in antigen handling.
T/F
F
They are not directly involved in that
T lymphocytes
Account for ______% of circulating lymphocytes
Found in the blood, T cell zones of peripheral lymphoid organs e.g. ______ of lymph nodes, ______ of the spleen
60-70
paracortical areas
periarteriolar sheaths
T cells recognize cell bound antigens by means of ____________
an antigen-specific T-cell receptor (TCR)
T cell receptor
The TCR is a disulfide-linked heterodimer of 2 polypeptide chains which may be ___ (___%) or ____
αβ; 95
γδ
T cell receptor
αβ (95% of T cells)– recognizes antigens __________
γδ (a minority of T cells)- ______________
presented by MHC molecules on the surfaces of antigen-presenting cells
does not require antigen presenting cells before they can bind antigens.
Exact function of γδ TCR is ????
but _________ where they are thought to _________.
not known
they aggregate at epithelial surfaces
be involved in immune surveillance
Knock out mice that cannot make γδ T cells are (slower or faster?) to heal injuries to their skin and are (more or less?) susceptible to skin cancers than normal mice.
Slower
More
Function associated molecules: CD4 and CD 8
Expressed on 2 mutually exclusive subsets of αβ T cells
CD4 is found on about ____% and CD 8 on about ____% of mature T cells
CD 4 molecules bind to Class ___ MHC molecules
CD8 molecules bind to Class __ MHC molecules
60
30
II
I
T cell diversity and TCR gene
rearrangements
T cell diversity is generated by _________
All ____ cells have TCR genes from the germ line
TCR gene rearrangements
somatic
Rearrangements of TCR genes occur only in _____
T cells.
Each T cell has a unique _______ and a unique ____ which is useful in differentiating _______ and _______ T cell proliferations
DNA rearrangement
TCR
monoclonal and polyclonal
End result of T cell activation is differentiation into ____ cells ( ____ or _____ cells) or ____ cells (T ___ cells)
T8; cytotoxic or suppressor
T4; Helper
CD4 cells
Are Activated by _______ and differentiate into _____ cells and _____ cells.
APC and IL-1
Helper T
memory T
The _____ T cell acts as a master regulator, secreting cytokines and influencing the function of other cells of the immune system including T cells, B cells, macrophages and NK cells.
CD4
2 types of T Helper cells:
T Helper 1 cells- secrete ____ and ____
T Helper 2 cells- secrete ____,____ ,_____ ,
IL-2 and IFN-γ,
IL-4, IL-5 and IL-13
delayed hypersensitivity
T helper 1 or T helper 2
Helper 1
macrophage activation
T helper 1 or T helper 2
1
synthesis of opsonizing and complement-fixing antibodies.
T helper 1 or T helper 2
1
synthesis of other classes of antibodies, notably IgE (mediated by ____,_____) and the activation of eosinophils (____).
T helper 1 or T helper 2
IL, 4 and IL-13
IL-5
T helper 2
CD 8 cells
Cytotoxic T cells
Activated by ___________ or by ________
-Activated cytotoxic T cells disrupt the _____ of infected cells, ____ them.
contact with antigen presenting APC’s
body cells infected with virus.
cell membranes
lysing
CD8 cells
Suppressor T cells
-Activated by _______ and ______
-it _________
contact with antigen and IL – 2.
Terminate the actions of cytotoxic cells
B lymphocytes
____% of circulating peripheral lymphocyte population and in peripheral lymphoid tissues such as lymph nodes ( ______ ) and spleen ( _____ ), or ____ and extralymphatic organs such as the ____.
10-20
superficial cortex; white pulp; tonsils
GIT
The end result of B cell activation is their differentiation into _____- secreting cells called ____ cells.
antibody
plasma
Natural Killer (NK) cells
Constitute ____% of circulating lymphocytes
Are CD__ negative (T lymphocytes are CD__ positive)
10-15
3; 3
NK cells
Express receptors for _____ (known as CD___) which enables them to _________
They also kill ____ infected and ____ cells
Fc of IgG; 16
lyse IgG coated cells
virus; tumour
Nk cells
They express _____ receptors for MHC I
inhibiting
Macrophages Belong to the class of APC
T/F
T
Macrophages
They take up ____, process it and present it to the ___ cells
antigens; T
Dendritic cells are APCs found in ______, interstitium of many organs and in the _____ ( ______ cells)
germinal follicles
skin
Langerhans
Major Histocompatibility molecules are antigens
T/F
F
Not antigens but antigen presenting cells
MHC
These molecules are critical to ___ cell immunity as these cells recognize only membrane-bound antigens
T
MHC
Encoded for by a cluster of genes on ____ arm of chromosome ___ called the major histocompatibility complex or the _________________ complex.
short
6
human leukocyte antigen (HLA)
Major Histocompatibility molecules
The genes are contained within ___ HLA loci known as _______
4
A, B, C and D.
MHC genes and gene products are classified into ___ classes based on their chemical structure, tissue distribution and function-
3
Class I MHC
- found in ___________
-encoded by __ closely linked loci – HLA- ______
it is a heterodimer consisting of ______ and ______ chain.
all nucleated cells and platelets
3; A, B and C,
polymorphic α and non- polymorphic β
Viral infection of a cell is associated with altered HLA class ___ expression on cell surface which is recognized by ____ and ____
I
CD8 and NK cells
Major Histocompatibility molecules
•Class II MHC- coded for in a region called HLA- ___with __ sub-regions- HLA- ______
-it is a heterodimer with _____ α and β chains.
-It is limited to ____.
D; 3
DP, DQ, DR
polymorphic
APCs
Class II MHC
They bind phagocytosed antigens and present them on their surface to be recognised by ______ cells
CD4 helper
Class III MHC- encode components of the ________
complement system.
Role of HLA in diseases
Individuals who inherit HLA alleles associated with specific diseases have a lesser chance of developing the disease than normal subjects do.
T/F
F
greater
2 random individuals can have the same HLA molecules
T/F
F
HLA genes are highly polymorphic hence, any 2 individuals except identical twins will have different HLA molecules which will be seen as foreign (allogeneic).
Examples of diseases associated with HLA alleles include _______ and other ______ with HLA B-27, _______ def with HLA-___, _______ with HLA-__, autoimmune endocrinopathies with the DR locus.
ankylosing spondylitis
arthropathies
21- hydroxylase; BW47
hereditary chromatosis ; A
ANTIGEN
Definition: A substance which the body recognizes as “ _____ ” and that triggers a ________
foreign; specific immune response
Complete antigen: A substance that ___________ and that can specifically ____________
induces an immune response
react with the product of that response (the antibody).
Incomplete antigen
Aka
______
Hapten
Incomplete antigen : A low-molecular-weight substance (a short peptide or drug) that only acts as an antigen once it ___________
binds to macromolecules
Physiology: The human immune system consists of about _____ lymphocytes and weighs about ____ kg.
It is composed of tissues belonging to the _______ and _______ systems.
1 x 1012; 1
lymphatic and reticuloendothelial
The immune organs include the following anatomic structures:
_______ Immune Organs
_______ Immune Organs
Central
Peripheral
THYMUS
Until the end of the ____ month of embryonic development, the thymus is purely ______ organ.
After that time, immature lymph cells migrate from hemopoietic embryonic tissue into the thymus.
There they are cared for by ____ cells ( _______ cells) and are programmed to distinguish between “self” and “non-self.” They then enter the bloodstream as “fighting lymphocytes” (T lymphocytes) and settle in the peripheral lymphatic organs
second; an epithelial
nurse; interdigitating
Central Immune Organs
BURSA OF FABRICIUS AND BONE MARROW
The bursa of Fabricius occurs only in ____ and is located near the ____.
_______ appears to have assumed the function of this organ in mammals and may therefore be regarded as its equivalent with respect to the ontogeny of the human immune system. Accordingly, the lymphocytes produced here are referred to as ____ lymphocytes.
birds; cloaca
Bone marrow
B
Peripheral Immune Organs
LYMPH NODES
The follicular cortical region with ______ and ______ and the medullary region with the sinus of the node contain _____
The paracortical region with its _____ follicles supplied by venules harbors ___ lymphocytes.
primary and secondary follicles
B lymphocytes.
tertiary; T
Peripheral Immune Organs
SPLEEN
Branches of the _____ artery, the _________ of the arteries of the _____ belong to the T-cell system,
whereas the splenic _____ and part of the ____ pulp belong to the B-cell system.
trabecular
periarterial lymph sheaths
splenic pulp
follicles; red
Peripheral Immune Organs
MALT
includes the following structures:
— Lymphatic _____ ring with the _____,_____, and ______ tonsils;
— Gut-associated lymphoid tissue (GALT), including the ____ in the duodenum, the ____ of the appendix, the _____ of the colon, and the ______ of the intestinal mucosa;
pharyngeal; pharyngeal, lingual, and palatine
Peyer’s patches; follicles; solitary follicles
immunocompetent cells
Peripheral Immune Organs
MALT
—_________ (BALT), including the lymphoid tissue in the ___________;
— Exocrine glands (_______ and ______);
Bronchi-associated lymphoid tissue
peribronchial fascial sheath
salivary glands and pancreas
The MALT is characteristically located in the __________ containing bacteria (gastrointestinal and respiratory tracts) and is in contact with ________ and other antigen material.
walls of hollow organs
pathogenic germs
Antigens from the intestinal tract are treated as follows:
The follicle-associated intestinal epithelium contains ______ cells (M cells), which pass antigens from the intestinal lumen to _________.
The absorbed antigen is received by _________ and _____ and treated in such a manner that ____________
They then enter the peripheral blood through the lymph system and ______
However, their ____ receptors enable them to find their way back to the _____ of their home vessels in the intestinal mucosa and in the other mucosa-associated lymphoid tissues.
membranous; intraepithelial lymphocytes
macrophages and dendritic cells
T cells and/or B cells in the adjacent lymph follicle are activated.
search for these antigens.
homing; endothelium
Antigen presentation to T cell by dendritic cells
MHC to ______
CD__ to CD___
TCR
80/86 to 28
Antigen presentation to T4 cell by B cells
MHC ___ to ____
CD___ to CD___
2; TCR
40: 40L
Heavy chain contributes to ________ regions. Light chain contributes to _______ regions.
Fc and Fab
only to Fab
Classic pathway of complement activation is by IG___ or IG___
G
M
C1 is a macromolecule
T/F
With proof
T
Has q,r,s
S is the recognition molecule
