lymphoid structures Flashcards by Ashley Hafer

functions of the LN (3)

nonspecific filtration by macrophages
storage and activation of B/T cells
antibody production

How well did you know this?

Not at all

Perfectly

3 regions of LN

cortex
paracortex
medulla

How well did you know this?

Not at all

Perfectly

what are located in the cortex?

B cells in follicles
1- inactive
2- active

How well did you know this?

Not at all

Perfectly

what are located in the paracortex?

T cells

How well did you know this?

Not at all

Perfectly

how do T cells and B cells from the blood inter LN?

through high endothelial venules located in the paracortex

How well did you know this?

Not at all

Perfectly

what is contained in the medullary cords? sinuses?

cords- lymphocytes, plasma cells

sinuses- reticular cells, macrophages

How well did you know this?

Not at all

Perfectly

lymphatic drainage of the rectum above the pectinate line

internal iliac nodes

How well did you know this?

Not at all

Perfectly

lymphatic drainage of the rectum below the pectinate line

superficial inguinal nodes

How well did you know this?

Not at all

Perfectly

lymphatic drainage of the testes

para-aortic nodes

How well did you know this?

Not at all

Perfectly

lymphatic drainage of the scrotum

superficial inguinal nodes

How well did you know this?

Not at all

Perfectly

lymphatic drainage of the lateral side of the dorsum of the foot

popliteal nodes

How well did you know this?

Not at all

Perfectly

right lymphatic duct drains (3)

right arm, right chest, right half of head; everything else drained by thoracic duct

How well did you know this?

Not at all

Perfectly

3 zones of the spleen

red pulp- RBCs
marginal zone- APCs
white pulp- WBCs

How well did you know this?

Not at all

Perfectly

location of T cells in spleen

PALS

How well did you know this?

Not at all

Perfectly

location of B cells in spleen

in follicles present in white pulp

How well did you know this?

Not at all

Perfectly

role of macrophages in spleen (2)

remove encapsulated bacteria and damaged RBCs

How well did you know this?

Not at all

Perfectly

consequences of splenectomy (4)

increased risk of infection from encapsulated organisms, Howell-Jolly bodies, target cells, thrombocytosis

How well did you know this?

Not at all

Perfectly

encapsulated organisms

SHiN SKiS
salmonella
H. influenza type B
Neisseria meningitidis
Strep pneumo
klebsiella
GBS

How well did you know this?

Not at all

Perfectly

thymus is derived from

3rd branchial pouch

How well did you know this?

Not at all

Perfectly

what occurs in the cortex of the thymus?

T cell positive selection- binding MHCI or MHCII

How well did you know this?

Not at all

Perfectly

what occurs in the medulla of the thymus?

T cell negative selection- destruction of cells that bind self antigens too avidly

How well did you know this?

Not at all

Perfectly

T cells leave the thymus as

naive T cells

How well did you know this?

Not at all

Perfectly

histologic feature of thymus

Hassals corpuscles

How well did you know this?

Not at all

Perfectly

only cells of innate immunity that have lymphoid origin

natural killer cells

How well did you know this?

Not at all

Perfectly

MHC I genes

A,B,C

MCHI locations

all nucleated cells

which type of cell lacks MHCI

RBC (no nucelus)

type of infection MHCI is involved with

viral

how are peptides loaded on to MHCI (3)

- antigen degraded in proteasome - travels through TAP into RER - loaded on MHCI

MHCII genes

DP, DR, DQ

MHCII locations

only APCs- macrophages, dendritic cells, B cells

type of infection MHCII is involved in

bacterial

how are peptides loaded on MHCII (5)

- MHCII synthesized in RER - MHCII transported to vesicle loaded with Ii - in vesicle, Ii replaced with CLIP - HLA-DM removes CLIP - peptide loaded in acidified endosome

CDs expressed on natural killer cells (2)

CD16, CD56

what is CD16? where is it found?

binds Fc region of antibodies found on NKCs, macrophages, neutrophils helps kill Ig-coated cells via ADCC

what is the action of natural killer cells?

kills tumor cells and virally infected cells using perforin/granzyme to induce apoptosis

substances that increase the activity of NK cells (3)

IL-2, IL-12, IFNb

NK cells are important for fighting what infection?/cells?

malaria-infected RBCs

absence of __ induces NK cells to kill

MHCI on cell surface

actions of interferons (2)

important for viral infections: decrease protein synthesis of neighboring cells and induce NK cells to kill

how do cytotoxic T cells kill? (2)

induce apoptosis via perforin/granzyme or Fas/Fas-L binding

Helper T cells induce Th1 with:

IL-12

helper T cells induce Th2 with:

IL-4

how are helper T cells activated? (2 signals)

both signals by antigen presenting cells signal 1- CD4 to MHC II signal 2- CD28 to B7

how are cytotoxic T cells activated?

signal 1- CD8 to MHCI (any cell) | signal 2- IL-2 receptor to IL-2 (Helper T cell)

how are B cells activated/class switching?

signal 1- B cell acted upon by cytokines | signal 2- CD40 to CD40-L (helper T cell)

what is anergy?

lack of activity by a lymphocyte due to lack of second activating signal

cells activated by Th1 cells (2)

macrophages, cytotoxic T cells

secreted by Th1 cells (2)

IFNg, IL-2

effect of IL-2

T cell proliferation

effects of IFNg (2)

activates macrophages, suppressed Th2 cells

secreted by Th2 cells (5)

IL-4, IL-5, IL-10, IL-13, IL-2

effect of IL-4 (2)

``` induces differentiation into Th2 class switching to IgE and IgG ```

effect of IL-10

inhibits Th1

what has similar activity to IL-10?

TGFb

what has similar activity to IL-4?

IL-13

effect of IL-5 (2)

``` class switching to IgA growth of eosinophils ```

expressed by regulatory T cells

CD3, CD4, CD25

role of regulatory T cells

suppress that actions of CD4 and CD8 T cells by release of IL-10 and TGFb

what Th type is active in viral infections?

Th1

part of the antibody that binds antigen

Fab = idiotype

part of antibody that determines isotype

composition of Fab

2 heavy and 2 light chains

what types of Ig bind complement? where?

IgM>IgG, near hinge point

types of heavy chains (5), determine?

alpha, gamma, mu, delta, epsilon | determines isotype

types of light chains (2), ratio?

kappa or lambda, normally 3:1

deviation from normal k:l indicates

neoplasia

where does isotope switching occur? How?

in germinal center of LN, under the influence of cytokines and CD40/CD40L interaction with helper T cells

3 general functions of antibodies

opsonization= promotes phagocytosis neutralization complement activation

2 most important means of generating antibody diversity

VDJ recombination | somatic hypermutation

where does VDJ recombination occur?

in the bone marrow, during B cell synthesis

how does VDJ occur?

initiated by RAGs which recognize RSSs flanking the V, D, J genes, respectively

what is the antibody "allotrope"? what can it be used for?

allotype = genetically determined, inherited markers on the heavy chain/can be used to determine paternity

antibodies expressed by mature B cells (2)

IgM, IgD

main antibody in the delayed/secondary antibody response

IgG

main antibody in the immediate/primary antibody response

IgM

most abundant antibody

IgG

antibody that crosses placenta

IgG

roles of IgG (3)

opsonizes bacteria, fixes complement, neutralizes bacterial toxins and viruses

antibody that protects mucosal surfaces

IgA

2 configurations of IgA

secretory form- dimer linked by J chain | circulating form- monomer

antibody secreted in breast milk

IgA

2 configurations of IgM

bound to B cell surface- monomer | circulating- pentamer

most effective antibody at activating complement

IgM

cells that IgE binds to (3)

mast cells, basophils, eosinophils

IgE actions

mediates type I HST reactions, kills worms

predominant antibody in AIDS

IgM (decreased CD4 T cells leads to decreased class switching)

thymus-independent antigens

lack peptide component = cannot be presented to T cells = will stimulate the release of IgM but no memory

thymus-dependent antigens

have peptide component = can be presents to T cells = class switching (IgG) and immunologic memory can occur

conjugated vaccines

conjugate polysacharide with protein to allow for thymus-dependent response and induction of memory