82. Where do B lymphocytes acquire immune competence?
(A) Thymus
(B) Bone Marrow
(C) Lymph nodes
(D) Spleen
Here’s an SEO-friendly article on the topic, optimized for search engines with a focus on the key phrase “where do B lymphocytes acquire immune competence.” I’ve structured it for readability, included the correct answer upfront, and provided clear explanations for all options to educate readers.
Correct Answer: Bone Marrow
B lymphocytes, or B cells, acquire immune competence in the bone marrow. This is option (B) in the multiple-choice question. Immune competence means these cells mature and gain the ability to recognize antigens and produce antibodies. Unlike T cells, B cells complete this process entirely within the bone marrow, making it their primary maturation site.
This fact is crucial for students studying immunology, as it highlights the division of labor in the immune system: bone marrow for B cells, thymus for T cells.
Detailed Explanation of All Options
Understanding why each option is correct or incorrect helps reinforce knowledge, especially for exams like NEET, USMLE, or biology coursework.
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(A) Thymus: Incorrect. The thymus is where T lymphocytes (T cells) acquire immune competence through positive and negative selection. B cells do not mature here; they originate from hematopoietic stem cells in the bone marrow and stay there for development. Mistaking this is common due to the similar “thymus” association with lymphocyte maturation.
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B) Bone Marrow: Correct. B cells develop from pro-B cells to immature B cells in the bone marrow. Key steps include V(D)J recombination for antibody diversity, receptor editing, and clonal selection. Only mature, self-tolerant B cells exit to circulate or enter peripheral lymphoid organs. In birds, this occurs in the bursa of Fabricius (hence “B” cells), but in mammals, it’s the bone marrow.
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(C) Lymph nodes: Incorrect. Lymph nodes are secondary lymphoid organs where mature B cells encounter antigens, proliferate, and differentiate into plasma cells or memory B cells. They do not acquire initial immune competence here; that’s already established in the bone marrow.
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(D) Spleen: Incorrect. Like lymph nodes, the spleen filters blood and supports mature B cell responses, especially against blood-borne pathogens. It’s a site for antibody production but not for B cell maturation or immune competence acquisition.
Why This Matters in Immunology
B cell maturation in the bone marrow ensures central tolerance—eliminating self-reactive cells before they enter circulation. Defects here can lead to autoimmune diseases like lupus. For researchers or students in Jaipur’s biotech hubs (e.g., near CSIR labs), grasping this supports studies in molecular immunology and vaccine design.
Quick Recap Table:
| Option | Role in B Cell Development | Correct for Immune Competence? |
|---|---|---|
| Thymus | T cell maturation | No |
| Bone Marrow | B cell maturation and competence | Yes |
| Lymph Nodes | Antigen encounter and activation | No |
| Spleen | Blood filtration and mature B cell response | No |
Search “where do B lymphocytes acquire immune competence” to dive deeper into resources like Abbas’ Cellular and Molecular Immunology.
