Unit 3 Adaptive Immunity Flashcards by michael perna

This type of immunity helps if innate immunity isn’t enough to clear an infection. It is found in jawed or higher vertebrates.

Is it specific or non-specific for individual foreign molecules

Adaptive Immunity

Highly specific

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What other important quality does the adaptive immunity have?

Memory of previous exposures, providing long term protection against re-exposure to the same pathogens

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What type of cells are B cells and T cells?

Lymphocytes (like NK cells)

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What are the names of receptors on T cells and B cells?

What are they specific for (what do they recognize on microbe?)

Do they work together?

TCR and BCR

Epitopes

Yes, on the same epitopes even

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These are portions of antigens that are actually responded to

Epitopes

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These receptors can only bind with epitope fragments, can’t bind when they’re still on the microbe, must be presented with that fragment

These can

TCR

BCR

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This has an IgD antibody (binds IgD), IgD antibody becomes secreted more frequently after it attaches initially

BCR

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Only _______ can bind antigens, which are on the surface of pathogens

The smallest part of an antigen that can be recognized is the __, its a clustering of AAs

Is there only one epitope or multiple on an antigen?

The B cell reacts with an epitope with a certain antibody, and that antibody is ultimately secreted

Immune receptors

Epitope

Multiple different epitopes, each capable of stimulating a response

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Where do B cells and T cells originate?

T cells migrate in a still immature stage to the ___ for further development

What do T cells learn in this place?

The bone marrow

Thymus Gland

Tolerance of body cell proteins

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The bone marrow and thymus are ____ ____ organs

Generative Lymphoid Organs

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During development, gene rearrangements produce a very large number of ____ and ____ to increase the chances of a reaction against pathogens, they are formed before exposure to pathogens

TCRs and BCRs

Also very diverse between different people, beneficial to our species

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Once mature, lymphocytes are expelled into the peripheral blood stream as mature, _____ lymphocytes

These cells migrate through ____ tissues distributed around the body, ready to respond to threats

naive

Lymphoid Tissues

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This is the second role of lymphocytes, other than immunity

This is the third role of them in the digestive system, they absorb lipids from foods we eat

Absorbs excess tissue fluids (like in elephantitis)

Lacteals

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What causes lymphocytes to move around?

Muscle contraction (bodily movement)

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What are the primary lymphoid organs

Bone marrow and thymus

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What does ‘naive’ lymphocytes mean?

Not yet encountered epitope receptor they are specific for

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Tonsils, spleen, lymph nodes, appendix, tespeyer’s patches areissues (have many lymphocy

Secondary Lymphoid Tissues

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This is a response after the primary response in adaptive immunity

Anamnestic (booster, memory)

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What is the main difference between the primary and anamnestic response?

The primary response produces ___ lymphocytes as a result

Days following response, 7-14 days for primary

Memory lymphocytes (Memory B and T cells)

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One of the important players of the adaptive immune response, multiple types are involved

They are involved with cell mediated side of adaptive immunity (aka destroy infected body cell, intracellular colonizer), B cells aren’t involved

They can also be involved in humoral response (extracellular), aka antibody response

T cells

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What are the three things that activation of T cells requires

Antigen Presentation
Cell signaling
Production of stimulatory responses

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Activated T cells expand and differentiate into their ___ cells or ____ cells

Effector, Memory

aka clones

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What are the three types of antigen presenting cells (like to T cells)

Macrophages
Dendritic Cells
B cells

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Cell signaling, required for activation of T cells, involves what molecules?

Cytokines

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These type of differentiated T cells work immediately These work later on, are in reserve for later for fast response

Effector Memory cells

A naive cell must interact with ____ to become dactivate This triggers...

Antigen presenting cell Differentiation into effector and memory cells (clonal expansion)

T cell activation requires binding of the TCR with the specific peptide presented on ____ molecules of APCs Can APCs be body cells?

MHC molecules (a presentation complex with epitope) Yes if they are infected by an intracellular colonizer, presents fragments growing inside of it

These are special groups of APCs for extracellular colonizers

Macrophage Dendritic cell B cell

T cells are very specific because they are produced in the ___ and mature in the _____ They are screened to avoid excessive ____ Good T cells with anti-foreign molecule TCRs are released into the

Bone Marrow, Thymus Self-reactivity Peripheral blood stream

Does one T cell have multiple receptor types or just many of one receptor?

Many of one receptor

How can one APCsactivate multiple different types of T cells?

They present multiple different epitope fragments with all of its MHCs

Co receptors on T cells also must correctly interact with the MHC molecule. It helps provide the correct ______ signal to the correct type of T cell This type interacts with MHC class II This type interacts with MHC class I

Activation CD4 (helper T) CD8 (killer T ,or cytotoxic T, Tc)

There are two types of helper Ts (CD4 cells) This type stimulates cellular immune responses, good for intracellular colonizers This type stimulates humoral (antibody) responses

TH1 TH2

So a T cell has a TCR and a co-receptor, the TCR binds to the ___ and the coreceptor binds to the ____

Epitope MHC complex

Which cells have MHC II complexes?

Macrophages, Dendritic cells, B cells

Establishing memory of previous exposure is a hallmark of ___ immunity _____ cells differentiate during initial adaptive immune responses. They are long lived, produce a faster and more rigorous response when the same antigen is encountered again, and the speed of the 2nd, 3rd, 4th, response can even prevent a repeat infection from occurring

Adaptive Memory cells

These are the action cells, which are short lived and armed with direct immune functions

Effector cells

In T cells, effector form depends on co receptors. In CD4+ T cells, secretion of large amounts of _____ enhance and direct actions of OTHER immune cells In CD8+ T cells, cytotoxic killing of infected cells by release of ______ near contacted target the cell, initiating apoptosis. Part of cellular immune response

Cytokines Granzymes/perforin (similar to NK cells)

In CD4 T cells, an antigen presenting cell, could be a body cell, is binded (twice, once epitope once MHC) by the T cell. The activated CD4 T cell secretes ____ and expression its receptor for autostimulation of that molecule Clonal expansion and differentiation produces a population of memory and effector TH cells

Interleukin-2 (IL-2)

This term means the cell releases a chemical which binds back to itself repeatedly, it actually makes more receptors for the chemical as well. Afterwards it divides and differentiation occurs

Autostimulation

In intracellular antigens and the endogenous pathway, ___ t cells are used

CD8 T cells (Killer T cells)

Killer T cells recognize targets by their presentation of antigen epitope fragments on ______ Killing is achieved by T cell release of ______, inducing apoptosis in a target

MHC 1 Perforin/Granzyme

So in CD8 T cells, antigen presentation and binding by the CD8 T cell occurs to the dendritic cell or macrophage The activated CD8 cell expresses a ____ receptor that binds ____ produced from TH cells Clonal expansion and diffrentiation produces a population of memory and effector Tc cells

interleukin-2 receptor IL-2

Which cells communicate with the activated Killer T cells? TH1 or TH2? The CD8 T cells will then divide

TH1 helper T cell

The cytotoxic T cell that was made from clonal expansion recognizes infected body cells by binding to the... Which binds first? TCR or CD8 co receptor? Do they both bind the MHC 1? What occurs to kill the body cell? The cell contents are degraded by

MHC 1 peptide complex with the epitope derived from the infecting microbe TCR Yes Degranulation Phagocytes

These are phagocytic cells that are very efficient at antigen reuptake, and thereby function as APCs. They are named for many long cytoplasmic extensions that resemble nerve dendrites What cells are they made from? They are formed where?

Dendritic cells Monocytes Bone Marrow

The innate functions of these cells include phagocytosis and intracellular killing

Macrophages

The APC functions of macrophages include presentations to memory ______ and ________ T cell subsets in secondary responses What else can they do?

CD4 and CD8 Determine the course of CD4 T-cell differentiation into particular subsets

These cells are critical for adaptive immunity. They produce ______ Also present MHC ____ peptide on their surface to CD4 Tcells

B cell antibody MHC II

What is the B cell receptor? B cell receptors trap foreign _____ It is ingested and broken into fragments. They are loaded onto MHC class ____ molecules Presentation to CD4 T cells occurs on TCR, causing them to secrete _____

IgD antigen II cytokines

These help the B cell to differentiate into an antibody secreting plasma cell or a memory B cell

Cytokines

Most B cells need the help of T cell ____ to become fully activated, and they can't get it without presenting antigens

Cytokines

Cytokine secretion by Th cells is required for activities of ___ cells and ____ cells But antibodies from them won't directly help kill or directly kill them, respectively. Because of the different immunity needs, there are two broad types of responses. What are they?

B cells and Tc cells Humoral Immunity Cell-mediated Immunity

This type of immune response is good against extracellular pathogens

Humoral

This type of immune response is good against intracellular pathogens

Cell-mediated

Th1 and Th2 are helper T cells that are a common link between the two types of ____ immunity Different subsets of helper T cells help in different ways by releasing different sets of ____ Which MHC do helper Ts present?

Adaptive Cytokines MHC II (both CD4 cells)

Which Th cell is involved in cellular immune responses? Which in humoral?

TH1 TH2

What are the 3 responses produced by TH1 cells

Specific inflammatory response Phagocytic Cell (macrophages/neutrophils) Activate Killer T (CD8)

Fast onset inflammation is caused by Slow onset is caused by

Histamine (innate) TH1

What does TH2 talk to to stimulate the production of antibodies? What is the APC in this instance?

B cells B cell as well. After talking to TH2 it differentiates into plasma cell to be able to produce antibodies

Which cytokines can suppress the activity of TH2 cells? What cytokines suppress the activity of TH1 cells?

TNFα, IFN-γ IL-10 & 13

Which cell is responsible for inflammation that ends up damaging our own body cells? TH1 or TH2? So which cytokine suppresses the inflammatory response

TH1 IL-10 & 13

Recall that our best understanding of how B cells produce antibodies is in response to protein antigens from foreign sources These responses usually require ____ help from helper T cells

Cytokine help from helper T cells

To produce antigen, B cells must first bind to the foreign antigen through the BCR, then ingest it and process it. Presentation of the antigenic peptide to the TCR on the helper T cell solicits the ____ help Which cytokines do this? The B cell multiplies, differentiating into antibody secreting plasma cells and _______ cells.

Cytokine help IL-4 and IL-6 Memory cells

In B cell responses to protein antigens, primary responses typically produce a modest amount of antibody after ______ days Secondary responses shift to much faster and larger scale antibody production Does the B cell retain the ability to respond to different antigens?

7-14 days Yes

Plasma cells can secrete 2100+ antibodies per Are plasma cells able to divide anymore? What is the term to describe this? What happens to the plasma cells in about 2 days? Do the antibodies last longer?

second No. Terminally differentiated. Apoptosis Yes, for weeks even

Antibody production by plasma cells in specific/nonspecific All antibodies from on eplasma cell are identical and will bind only to a single ___ on an antigen

RVery specific Epitope

Recall that a single antigen may have many ____ - so many different plasma cells can be formed, each with a different specificity

Epitopes

This antibody (glycoprotein) has 2 heavy chains and 2 light chains forming a Y shaped structure What type of bonds exist within and between chains?

IgG Disulfide Bonds

The two arms of the Y in IgG form what? The bottom of the Y forms what?

Antibody binding fragments (Fab) aka where epitope binds Region that self receptors bind to

IgG has variable and constant regions on the heavy and light chains. Variable regions can be different between different IgG antibodies

The variable regions bind unique epitopes while the constant regions bind the same between different IgGs

A region of IgG made of the constant heavy chain and another constant heavy chain

Fc region

This region of IgG binds complement and Fc receptors on phagocytes to allow the white blood cell to conduct phagocytosis The IgG acts as what?

Fc region Opsonization factor

This antibody is the main part of the B cell receptor, its not released to do a job elsewhere.

IgD

The use of diferent C-region gene segments leads to different classes of antibodies. Each class has slightly different structures and functions in immune responses. This phenomena is called

Antibody class switching (aka phenotype switching)

Which antibody is always the first antibody in a primary response? Why is IgM made first? The complex class switching process can change the type to make the most efficient response to make what antibodies?

pentomeric IgM (p IgM) 5 IgM monomers means there are 10 binding sites IgA,IgE, IgG

What are the same between the IgA, IgE, and IgE What is different?

Variable light variable heavy chains (they must bind to the same antigen that triggered IgM production in the 1st place) The constant region is different

This class of antibody is a dimer, found in tears, milk saliva, aka mucosal membranes. Also called secretory antibody. How many binding sites, then?

IgA Dimer = 4 binding sites

First type most pathogens encounter because its in the mucosal membrane...

IgA

This is the most abundant antibody because of the amount of surface area on mucosal membranes

IgA

These are monomer antibodies associated with eosinophils and allergic reactions.

IgE

IgEs bind to what two cell types, causing degranulation and inflammation? What is the chemical released that causes inflammation?

Basophils and mast cells Histamine

This antibody is a monomer, and is the most present antibody in the serum (in our blood) to activate complement cascade.

IgG

This monomer antibody can cross the placenta because its small to protect the baby.

IgG

The functions of antibodies

Blocks binding of pathogens/toxins on host cells (binding to the pathogen) Fixes complement to bacterial structures for lysis Opsonization Agglutination Activations eosinophils, basophils, and mast cells by providing an exposed FC region for cells to bind to

This is clumping of antigen caused by antibodies increasing phagocytosis

Agglutination

NKs respond to MHC 1 missing NK T cell responds to epitopes presented to them on MHC 1, more specific Both are lymphocytes

___ immunity can cause damage to our structures if it is inappropriately of excessively damaged

Adaptive

Th1 cells and Th2 -------> MHC II CD8 aka killer T's have ---------> MHC I