BLOCK 3: IMM: (3.1) INTRO TO B-CELLS AND DEVELOPMENT

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Questions and Answers

What is a key characteristic that distinguishes adaptive immunity from innate immunity?

Adaptive immunity involves memory response. (correct)

Adaptive immunity does not involve cells.

Adaptive immunity is present at birth.

Adaptive immunity has a faster response time.

Which of the following accurately describes the role of B cells in the adaptive immune system?

B cells are responsible for direct cell killing.

B cells participate exclusively in the innate immune response.

B cells primarily activate macrophages.

B cells produce antibodies in response to antigens. (correct)

Where do B cells primarily develop during gestation?

Lymph nodes

Thymus

Bone marrow (correct)

Spleen

What role do bone marrow stromal cells play in B cell development?

They aid in the differentiation and maturation of B cells. Signup and view all the answers

Which organs are considered primary immune organs where adaptive immune cells mature?

Bone marrow and thymus Signup and view all the answers

Where do B cells primarily differentiate into their functional form?

Bone marrow Signup and view all the answers

What is the primary function of plasma cells?

To produce and secrete immunoglobulin Signup and view all the answers

Which characteristic is NOT associated with plasma cells?

Stained Golgi apparatus Signup and view all the answers

At what stage of human development are the progenitors of B cells first found?

3rd week of gestation Signup and view all the answers

What happens to BCRs once B cells become activated?

They are synthesized and secreted as antibodies Signup and view all the answers

What is one of the primary functions of the adaptive immune system?

It has the ability to recognize and remember specific pathogens. Signup and view all the answers

Which process is NOT associated with the humoral immune response?

Destruction of invading cells by leukocytes Signup and view all the answers

Where do B-cells primarily develop and differentiate?

In the bone marrow, where they remain as mature lymphocytes Signup and view all the answers

Which of the following statements about lymphocytes is FALSE?

Lymphocytes are produced in the thymus. Signup and view all the answers

Which mechanism describes how antibodies prevent microbial spread?

Agglutination and phagocytosis Signup and view all the answers

What type of receptors are displayed on B cells' surfaces?

Immunoglobulins (BCR) Signup and view all the answers

Which of the following statements about B-1 and B-2 cells is true?

B-2 cells are continuously replaced from the bone marrow. Signup and view all the answers

What characterizes the response of each B cell?

Each B cell produces immunoglobulin of only one specificity. Signup and view all the answers

Where do B cells primarily develop?

Bone marrow Signup and view all the answers

How do plasma cells differ from B cells?

Plasma cells produce and secrete immunoglobulin. Signup and view all the answers

Study Notes

Adaptive vs. Innate Immune System

Adaptive system acts when the innate system fails
Features:
- Immunological memory to recognize specific pathogens via antigens
- Antibody Production
- Humoral Immune Response - Prevents microbial attack using "fluids"
  - Antibodies recognize microbial epitopes to:
    - Immobilize microbes
    - Prevent microbial attachment to host cells
    - Promote microbial phagocytosis
    - Target microbial destruction by soluble molecules or leukocytes
- Cell-mediated Immunity- leukocytes destroy invading cells

Lymphocytes

Produced in bone marrow but travel through the lymphatic system
Differentiate in lymphoid tissues:
- Lymph Nodes
- Thymus
- Spleen

B Cell Development

Hematopoietic stem cells in bone marrow become common lymphoid precursor (CLP)
CLPs can differentiate into either:
- T cells: Develop in the thymus
- B cells: Remain in bone marrow
B cell "graduates" can be differentiated by:
- Education level
- Arrival and departure from bone marrow
- BCR diversity
- Geographic distribution in the body
- Nature of responses to antigens

B Cell Basics

Do not migrate to the thymus, develop within the bone marrow
Arise from HSCs in the bone marrow, with two lineages:
- B-1 cells: Self-renewing population that dominates the plural and peritoneal cavities
- B-2 cells: Conventional cells, arise during and after the neonatal period, continuously replaced
  - Widely distributed throughout lymphoid organs and tissues
Each B cell is specific, producing immunoglobulin with one specificity, recognizing only one epitope.
Diversity amongst B cells, each producing a single form of immunoglobulin, creates the overall diversity of the immunoglobulin response.

Plasma Cells

Derived from terminally differentiated B cells
Immunoglobulin-producing and secreting cells
Characterized by basophilic cytoplasm, a nucleus with a stellate pattern, and a non-staining Golgi.
Cease using immunoglobulin as a membrane receptor and secrete it into surrounding fluids.
Secreted immunoglobulin is known as antibodies.
Increase in size and metabolic activity to produce high quantities of immunoglobulin during their short lifespan.

B Cell Lineage Overview

Progenitors of immunoglobulin-producing cells are found during gestation:
- 3rd week: Yolk sac
- 8th week: Fetal liver
- 12th week: Bone marrow
Also called bone marrow-derived lymphocytes or B cells - this is where they differentiate.
B cells synthesize immunoglobulin and display it on their surfaces as BCRs.
Once activated, they differentiate into plasma cells which synthesize AND secrete their BCR as an antibody.

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Description

Test your knowledge on the adaptive and innate immune systems. This quiz covers key features, the role of lymphocytes, and B cell development, providing insights into how these systems work together to protect the body from pathogens. Perfect for students of immunology and biology.