Immuno: EXAM 3- Ch.4- Structure of Lymphocyte Antigen Receptors + Development of Immune Repertoires

All info from Ch.4 study guide, slides, and textbook (monoclonal antibodies forward)

What medium is used to create monoclonal antibodies? How does it work?

HAT medium which selects for immortalized hybridoma cells by blocking the de novo pathway which unfused myeloma cells rely on

What genes do B cells provide to myeloma cells in monoclonal antibody production? What pathway are both of these involved in?(2)

TK and HGPRT; salvage pathway

What pathway do B cells use to survive in monoclonal antibody production? What pathway do UNFUSED Myeloma cells rely on?

salvage; de novo

What does the HAT medium block that stops the ‘de novo’ DNA synthesis pattern? What molecule in the HAT medium is responsible for this block?

THF reductase; Aminopterin

Its derived from a single B cell clone will always be _____( genetically)? (monoclonal antibodies)

homogenous

How can monoclonal antibodies be genetically engineered to be less immunogenic to humans?

They can edit the antibodies to retain the Antigen binding V region of the mouse antibody, but replace the rest with human a Ig skeleton

What is a risk of prolonged use of humanized monoclonal antibodies in humans?

The body may create anti-Ig Igs which attack the mouse antigen binding regions

How can the mice themselves be genetically altered to reduce the chance of an immune response to mouse made monoclonal antibodies?

The mouse’s Ig genes can be replaced with Human Ig genes using recombinant DNA technology, so that when the mouse is immunized with the antigen, they will produce the antigen specific HUMAN antibodies (Igs)

What are monoclonal antibodies used for?

Therapeutic and diagnostic agents for disease and can be used for the identification and quantification of structures on/in cells, fluid, or tissue samples

What are hybridomas? What are their 2 traits?

The combination of mouse B cells and myeloma cells which secrete antibodies against a specific antigen and are immortal

What is the basic structure/ description of the TCR?

Membrane bound heterodimer composed of alpha and beta chains

What is the TCR analogous to? How is each part analogous?

Ig Fab region; The TCR alpha chain is like the Ig light chain and the beta chain is like the Ig heavy chain

What does the TCR recognize? (1)

peptide-MHC complexes

What are the 2 regions of the TCR?

V and C regions

What region in TCR/BCRs are the antigen-recognizing domains?

the V region

What are CDRs?

Complementarity-determining regions which are in the V region of TCR/BCR which are concentrated in small regions of the receptor to maximize variability of antigen bindingg regions

How many CDRs are in each V region of TCRs? What CDR is the most variable?

Three CDRs, CDR3

In TCRs, which chain are involved in peptide-MHC recognition?

Both alpha and beta chains

Can the TCR transmit signals to the T cell on its own?

No

What in the TCR allows it to transmit signals to the T cell?

CD3 and ζ proteins and CD4 or CD8 coreceptors

What do CD4 and CD8 coreceptor molecules do in TCR? (2)

recognize nonpolymorphic portions of MHC molecules and transmit signals

What do the signals released by C regions in TCR/BCRs do? (where and what?)

They are transmitted to the cytosol and the nucleus and may cause the lymphocyte to divide, differentiate, perform effector functions, or die

What are epitopes?

The part of antigens that are recognized by antibodies

TCRs recognize peptide MHC complexes and bind to antigens with ____ affinity?

low

What do adhesion molecules do for TCRs?

strengthen binding of T cells to APCs

Igs bind to many different chemical structures with _____ affinity

high

Where are Igs found?

The circulation and lumens of mucosal organs

What are the 4 major differences between the 3D structure of TCR and the Fab region of an Ig molecule?

TCR alpha/beta chains are anchored in the plasma membrane, TCRs are never secreted, and TCRs do not undergo isotope switching or affinity maturation

What are γδ TCR ? (prevalence in body, what is the difference?, Where are they found? What could they do?)

5-10% of T cells, recognize variety of protein and non protein Ags not displayed by classical MHC molecules, abundant in epithelial and may recognize microbes within epithelial surfaces

How does the clonal selection hypothesis help explain how B & T lymphocyte development lead to the diversity of receptors?

The hypothesis states that there are 10^9 clones of B and T lymphocytes with distinct specificities that arise before encounter with antigens, but there are not enough genes in the human genome for every possible receptor to be encoded genetically, which means that the generation of diverse receptors is ultimately linked to the maturation process

What does IL-7 do in lymphocyte development?

maintains and expands the number of T cell progenitors / controls T cell proliferation