Advanced Immunology: Understanding Lymphoid Organs and Cell Differentiation

1. The primary lymphoid organs, or generative organs, are those in which lymphocytes mature. This includes:

2.) Digestion of proteins

1.) Maintenance of homeostasis

3.) Regulation of blood pressure

1.) Expression of receptors 2.) Positive and negative selection 3.) Attaining functional and phenotypic maturity

The primary lymphoid organs are responsible for the development and maturation of lymphocytes, specifically involving the expression of receptors, positive and negative selection, and attaining functional and phenotypic maturity.

Explanation

The primary lymphoid organs are responsible for the development and maturation of lymphocytes, specifically involving the expression of receptors, positive and negative selection, and attaining functional and phenotypic maturity.

2. Where is the major site of hemopoesis before birth?

Fetal liver

Placenta

Spleen

Bone marrow

Hemopoesis is the production of blood cells. Before birth, the major site of hemopoesis is the fetal liver. While bone marrow is the primary site of hemopoesis after birth, it is not the major site before birth. The spleen also plays a role in blood cell production, but it is not the main site before birth. The placenta is involved in nutrient and oxygen exchange between the mother and fetus, but it is not a site of hemopoesis.

Explanation

Hemopoesis is the production of blood cells. Before birth, the major site of hemopoesis is the fetal liver. While bone marrow is the primary site of hemopoesis after birth, it is not the major site before birth. The spleen also plays a role in blood cell production, but it is not the main site before birth. The placenta is involved in nutrient and oxygen exchange between the mother and fetus, but it is not a site of hemopoesis.

3. What drives the differentiation of bone marrow stem cells?

Cytokines

Enzymes

Antibodies

Hormones

Bone marrow stem cells differentiate into various blood cells under the influence of cytokines, which are signaling proteins that regulate the differentiation and proliferation of cells. Hormones, enzymes, and antibodies do not play a direct role in the differentiation of bone marrow stem cells.

Explanation

Bone marrow stem cells differentiate into various blood cells under the influence of cytokines, which are signaling proteins that regulate the differentiation and proliferation of cells. Hormones, enzymes, and antibodies do not play a direct role in the differentiation of bone marrow stem cells.

4. In cell differentiation, which stage is characterized by a cell that does not express membrane immunoglobins?

Pro- B cell

Plasma cell

Naive T cell

Memory B cell

In cell differentiation, pro-B cells are the earliest stage of B cell development and are characterized by the lack of expression of membrane immunoglobins.

Explanation

In cell differentiation, pro-B cells are the earliest stage of B cell development and are characterized by the lack of expression of membrane immunoglobins.

5. In Pro-B cell (1st stage of cell differentiation) there is gene rearrangement to produce a ____ chain.

U (mu) heavy chain

Alpha light chain

Delta light chain

Gamma heavy chain

During the 1st stage of cell differentiation in Pro-B cells, gene rearrangement occurs to produce the u (mu) heavy chain. This process is crucial for the development of B cells and the eventual production of functional antibodies.

Explanation

During the 1st stage of cell differentiation in Pro-B cells, gene rearrangement occurs to produce the u (mu) heavy chain. This process is crucial for the development of B cells and the eventual production of functional antibodies.

6. In cell differentiation, once the mu heavy chain is actually synthesized, the cell becomes a ______.

B cell

Pre-B cell

Plasma cell

Natural killer cell

During cell differentiation, once the mu heavy chain is synthesized, the cell enters the Pre-B cell stage where further development towards becoming a mature B cell takes place. The other options do not accurately represent this specific stage in cell development.

Explanation

During cell differentiation, once the mu heavy chain is synthesized, the cell enters the Pre-B cell stage where further development towards becoming a mature B cell takes place. The other options do not accurately represent this specific stage in cell development.

7. What receptor does the Pre-B cell produce?

T-cell receptor

Antigen receptor

Pre-B cell receptor

Natural killer cell receptor

The Pre-B cell produces its specific receptor known as the Pre-B cell receptor, which plays a crucial role in B cell development and maturation.

Explanation

The Pre-B cell produces its specific receptor known as the Pre-B cell receptor, which plays a crucial role in B cell development and maturation.

8. After rearranging light chain genes, a pre-B cell becomes an _______ .

Immature B cell

Mature B cell

T cell

Plasma cell

After rearranging light chain genes, a pre-B cell goes through further stages of development before reaching maturity as a B cell.

Explanation

After rearranging light chain genes, a pre-B cell goes through further stages of development before reaching maturity as a B cell.

9. The B cell receptor produced by pre-B cells are Ig__ only.

IgA

IgE

IgD

IgM

Pre-B cells initially produce IgM as their B cell receptor, which later can undergo class switching to produce IgA, IgE, or IgD. However, the initial product is IgM.

Explanation

Pre-B cells initially produce IgM as their B cell receptor, which later can undergo class switching to produce IgA, IgE, or IgD. However, the initial product is IgM.

10. Immature B cells that are strongly stimulated by self-antigen at this point either die by apoptosis or are inactivated. This process is known as?

Neutral selection

This is negative selection

Positive selection

Random selection

Negative selection is the process where immature B cells that strongly react to self-antigens undergo apoptosis or inactivation to prevent autoimmune responses. Positive selection, neutral selection, and random selection are not accurate terms for this particular process.

Explanation

Negative selection is the process where immature B cells that strongly react to self-antigens undergo apoptosis or inactivation to prevent autoimmune responses. Positive selection, neutral selection, and random selection are not accurate terms for this particular process.

11. Where do the surviving immature B cells mature, migrate to express surface IgD (as well as IgM), become competent, and populate secondary lymphoid organs?

Spleen

Thymus

Bone marrow

Liver

Immature B cells undergo maturation in the bone marrow before migrating to the spleen, where they express surface IgD (as well as IgM), become competent, and populate secondary lymphoid organs.

Explanation

Immature B cells undergo maturation in the bone marrow before migrating to the spleen, where they express surface IgD (as well as IgM), become competent, and populate secondary lymphoid organs.

12. When Pre-B cells rearrange light chains (kappa and lambda), the result is 1 kappa and 1 lambda.

False!Always 2 kappa and 2 lambda

True! Always 2 kappa and 1 lambda.

False! Sometimes 1 kappa and 1 lambda.

True! Only 1 kappa and 1 lambda.

During B cell development, each B cell will express either kappa or lambda light chains, not both. The general rule is that Pre-B cells rearrange two kappa alleles first, and if they are unsuccessful, they rearrange two lambda alleles. Therefore, the correct answer is False! Always 2 kappa and 2 lambda.

Explanation

During B cell development, each B cell will express either kappa or lambda light chains, not both. The general rule is that Pre-B cells rearrange two kappa alleles first, and if they are unsuccessful, they rearrange two lambda alleles. Therefore, the correct answer is False! Always 2 kappa and 2 lambda.