Immunology: B and T Cell Development, Responses, and Laboratory Techniques

What is the role of bone marrow in B cell maturation?

Bone marrow is where B cells originate and mature.

Where do immature T cells complete their maturation?

In the thymus.

What are the stages of B-cell differentiation?

Pro-B cells, Pre-B cells, Immature B cells, Mature naïve B cells.

What is the significance of positive selection in T cells?

Thymocytes must weakly bind self-peptide complexes to survive and mature.

What happens during negative selection in T cells?

Thymocytes are exposed to self-peptides; those that bind strongly are eliminated.

What is receptor editing in B cells?

A process where B cells whose BCRs bind strongly to self-antigens can rearrange their light chains to alter specificity.

Differentiate between antigen-independent and antigen-dependent B cell responses.

Antigen-independent responses activate B cells without T-cell help; antigen-dependent responses require T-cell interaction.

Which cells recognize MHC Class I and II?

MHC Class I is recognized by CD8+ T cells; MHC Class II is recognized by CD4+ T cells.

What are the stages of T cell differentiation?

Double Negative (no CD4 or CD8), Double Positive (both CD4 and CD8), Mature T cells (either CD4+ or CD8+).

Which cells utilize perforin and granzymes?

Cytotoxic CD8+ T cells and Natural Killer (NK) cells.

What type of cells do cytotoxic T cells primarily target?

Virally infected cells.

What are the main functions of Th1 cells?

Activates macrophages, supports cell-mediated immunity, and helps CD8 T cell responses.

What do Th2 cells promote?

B cell proliferation and antibody production, especially IgE.

What is the role of dendritic cells in the immune response?

They process and present antigens to T cells via MHC in lymph nodes.

What is the purpose of flow cytometry in immunology?

It is used for the differentiation of lymphocytes.

How is dilution defined in laboratory settings?

Dilution = volume of sample / total volume.

What is a titer?

The highest dilution of a sample that still gives a positive reaction.

Differentiate between precipitation and agglutination reactions.

Precipitation involves soluble antigens forming a precipitate; agglutination involves antigens attached to particles clumping together.

What is hemagglutination?

A specific type of agglutination involving the clumping of red blood cells.

What does the law of mass action describe?

It describes how the rates of forward and backward reactions depend on the concentrations of reactants and products.

What is nephelometry used for?

To measure the amount of light scattered by particles in a solution.

What is endpoint RID?

The point at which the precipitin ring stops expanding, indicating equilibrium.

What is the difference between prozone and postzone?

Prozone: Excess antibodies prevent visible precipitation; Postzone: Excess antigen prevents effective cross-linking.

What is the relationship between enzyme activity and patient analyte in a direct ELISA?

There is a direct relationship.

What is bound in the solid phase of sandwich/capture assays?

The capture antibody.

What is the difference between direct and indirect immunofluorescence?

Direct uses a fluorescent dye conjugated to the primary antibody; indirect uses a secondary antibody to bind the primary.