Cells and Tissues of the Immune System

Hematopoiesis is the creation of ___.

Process starts in the BM as a Multipotent cell called: ___ stem cell. Where it can follow 2 different lineages: ___/Erythroid progenitor cell or ___ progenitor cell.

cells; hematopoietic; Myeloid; Lymphoid

Immunology focuses on these cells in the Myeloid lineage:

-eosinophil
-basophil
-monocyte
-neutrophil

Immunology focuses on these cells in the Lymphoid lineage:

-T cell
-B cell
-NK cell

Lymphocytes are __-40% of peripheral WBCs.

Major types include: __ lymphs (T + B cells) and large lymph (__ cells).

You cannot differentiate between T and B cells by eyes, you would need ___ testing.

20; small; NK; further

To differentiate cells, we need ___ (Cluster of Differentiation) Markers.

Each cell has a very ___ set of these markers! It is used to determine what it is to track numbers or treatment, etc.

CD; specific

B Cells make up half of circulating lymphs, ___-20%.

Markers include:

-IgM and ___
-Fc receptor for ___ heavy chain
-___ for complement (CD35)
-___ molecules
-CD___

IgD; IgG; receptor; MHCII; 19

B Cell Maturation starts in the ___ ___ → (starts ~2 mon) liver + spleen → (start ~5 mon) ___ marrow

The two stages of differentiation are: Antigen Independent and ___

yolk sac; bone; dependent

In the B Cell Maturation process, a stem cell becomes a ___-B Cell that is ___ to BM stromal cell.

Pro; connected

Pro-B cells become ___-B cells when ___ (μ) chains start to accumulate in cytoplasm.

Pre; mu

Once μ chains become very accumulated in Pre-B cells, they become ___ and are now present on the cell surface! This cell is now called an ___ B cell.

IgM; immature

Immature B cells must undergo ___ selection, a process where self-antigens are presented to the B cell to see if they self-react. If they react, they will be forced to go through ___.

negative; apoptosis

If a immature B cell passes negative selection (they do not react), they leave the BM to the ___ ___ or spleen to finish maturation.

Lymph nodes

Which steps of the B cell maturation cycle take place in the bone marrow?

Stem, Pro, Pre, Immature, and neg selection

After an immature B cell leaves the BM, it gains IgM AND ___ - and is now considered ___.

IgD; mature

List the steps of B cell maturation from stem cell → mature B cell

Stem, Pro, Pre, Immature, Neg Selection, Mature Cell

Mature B cells hang in ___ and secondary lymphoid waiting for an ___ to respond to.

spleen; antigen

When an antigen is presented to a Mature B cell and ___ to IgD and/or IgM, a response is triggered and ___ the B cell.

binds; activates

After an antigen binds to a mature B cell’s IgD and/or IgM, IgM ___ occurs and the B cell is now activated.

This is when IgM ___ to one side of the cell after presented an antigen.

capping; migrates

A mature B cell can turn into specific types of cells with the help of ___. This includes ___ cells (makes antibodies), ___ (antibodies themselves), and ___ cells after first exposure.

cytokines; plasma; immunoglobulins; memory

T cells make up ___-80% of circulating lymphocytes.

List the 4 important CD Markers:

60; CD2; CD3; CD4; CD8

Which CD markers do all T cells have?

CD2 and CD3

The CD marker for T Helper cells is ___.

CD4

The CD marker for Cytotoxic T Cells is ___.

CD8

T Cell differentiation starts with an ___ T-cell leaving the BM and entering the ___ to mature.

immature; Thymus

A double negative (DN) cell is an immature T cell who lacks both ___ and ___ (is unemployed).

A double positive (DP) has ___.

CD4; CD8; both

Immature T cell will first become a ___ cell, as it develops it will form both CD4 and CD8 to become a __ cell.

DN; DP

DP cells must undergo ___ selection - a mechanism that tests both CD markers react to ___I or II markers, making sure the cell ___ to what it’s supposed to react to.

positive; MHC; reacts

In T Cell Differentiation, the process from immature T cell to positive selection takes place in the Thymus ___.

cortex

In T Cell differentiation, Positive selection requires the “goldilocks” condition (needs to be just right).

Too strong of a bind between CD4/CD8 to MHC I or II= ___. Leading to ___.

Too weak of a bind between CD4/CD8 to MHC I or II= no ___. Leading to apoptosis.

Intermediate binding between CD4/CD8 to MHC I or II= just right. Passing positive selection and becoming a ___-positive cell (either T helper CD4 or Cytotoxic CD8).

Whichever marker is more ideal stays, the other gets ___ off! Only ONE can win!

autoimmune; apoptosis; reaction; single; cleaved

After development of a single pos cell, it moves to the ___ of Thymus to undergo ___ selection. If it passes, it will exit the Thymus and enter the body as a ___ T cell CD4 or CD8.

medulla; negative; mature

The T Cell Differentiation whole maturation takes about ___ weeks and only about ___% of T cells survive and exit the thymus (due to pos/neg selection).

3; 1

Pos selection - tests cells ability to react with what it is ___ to (cannot be too strong or too weak - must be ___)

Neg selection - tests cells against ___-antigens to make sure they do ___ react against self.

supposed; intermediate; self; not

T Cell subpopulations includes CD4+ Helper T Cells (Th1 + Th2) and CD8+ Cytotoxic T Cells.

T Helpers ___ other cells (such as B cells). Cytotoxic T cells destroy ___ infected or ___ cells.

helps; virally; tumor

Natural Killer (NK) Cells are ___ lymphocytes that make up ___-10% of circulating lymphs.

It’s specific marker is CD__: Fc receptor for ___.

It plays a role in ___-dependent cell mediated cytolysis. It also lyses virus infected or tumor cells without needing ___ immunization (innate).

Large; 5; 16; IgG; antibody; prior

Receptors on the NK cell recognize the ___ and release ___ granzymes, signaling the cell to die.

antibody; perforin

NK Cells can also kill in two different ways: Antigen-dependent and Antigen-Independent.

Antigen-dependent NK Cells require an ___ present on the infected cell to bind and kill the cell by releasing granules and enzymes.

Antigen-independent NK cells will kill a cell that does not have the ___-antigen (MHCI) present since it will automatically recognize it as a tumor cell. (NOTE: every cell in body has a MHC1 cell!)

antigen; self

Monocytes/Macrophages make up ___-10% of circulating nucleated cells. Their two main functions are ___ and antigen presentation (MHC___).

Monocytes and Macrophages are the same thing but it two different locations. Monocytes = blood and Macrophages = ___.

4; phagocytosis; II; tissue

Neutrophils make up most of the body’s circulating nucleated cells around ___-70%. It is considered the ___ effective cell at Phagocytosis.

It also plays a role in acute inflammation, but it is very ___-lived. (few hours)

50; most; short

Eosinophils make up ___-3% of circulating nucleated cells and protect against ___ infections. It also ___ allergic responses.

1; parasitic; dampens

Basophils/Mast Cells make up ___% of circulating nucleated cells.

Mast cells are basophils that are found in the thymus, spleen, lung, GI tract, and bone marrow.

Markers include the Fc receptor for ___ heavy chain. They are also involved in ___ reactions and their granules affect ___.

IgE; Hypersensitivity; vasodilation

Primary Lymphoid Organs are the major sites of lymphopoiesis, an area for cells to ___. It includes the fetal ___, ___ ___, and ___.

liver; bone marrow; thymus

Secondary Lymphoid Organs creates an environment for ____, by trapping antigens, providing space for lymphocyte-____ interactions, and ___ the immune response products.

It includes the ___ nodes, ___, and ___.

interaction; antigen; exporting

Lymph; spleen; MALT

The spleen is an encapsulated organ that ___ blood - the total volume goes through ___x daily! It removes old/damaged cells and invading organisms.

Components:
Red pulp = destroys damaged ___.
White pulp = contains ___ and ____ (where antigen-lymphocyte reaction occurs)

filters; 4; RBCs; lymphocytes; macrophages

Lymph nodes are encapsulated organs strategically located along the lymphatic vessels where all lymph cells ___.

It filters lymph fluid and ___ invading organisms.

travel; traps

Mucosal Associated Lymphoid Tissue (MALT) is non-encapsulated. It includes your ___, adenoids, Peyer’s patches.

Considered first line of defense for ports of entry that are ___ or ingested (respiratory, gastrointestinal, urogenital tracts).

tonsils; inhaled

Cells ___ and are NOT stationary. Migration happens via circulatory and ___ systems.

Lymphs can circulate among secondary organs and ___ to the blood, increasing the likelihood that they will encounter ___ organisms.

migrate; lymphatic; invading