Question

In: Biology

Hi, for this question please explain in detail and only use correct information. This question is...

Hi, for this question please explain in detail and only use correct information. This question is related to immunobiology

List the B-cell developmental stages from pre-pro to immature B cells describing B-cell receptor (BCR or Ig) rearrangements occurring and/or key events occurring at each stage.

Solutions

Expert Solution

In adaptive immunity, the main function of the B cells is to secrete the antibodies that bind to the pathogens or the toxic products produced by the pathogens in the extracellular space of the body. The white blood cells, lymphocytes of the adaptive immunity have evolved to identify and fight against the broad range of pathogens. The immunoglobulins or Ig are the antigen-recognition molecules of the B cells. B cells produce these proteins in a wide range of the antigen specificities, each immunoglobulin produced by the B cells have a single specificity.

The BCR (B-cell receptor) is the membrane-bound immunoglobulin present on the surface of the B cell that serves as a receptor for the antigen. The terminally differentiated B cells, plasma cells secrete the immunoglobulin of the same antigen as an antibody. In adaptive immunity, the main function of the B cells is to secrete the antibodies that bind to the pathogens or the toxic products produced by the pathogens in the extracellular space of the body.

The development of the B cells begins in the liver of the fetus and continue throughout life in the bone marrow.  B cell officially develops completely when is eligible to express both L and chains present on its membrane. It is still immature because it can still be killed on coming in contact with the self-antigen until it can also express membrane IgD. The mature B cell traverses to the periphery and is activated by the antigen to become plasma cells that secrete antibody or a memory B cell that responds to the second exposure to antigen more quickly. The B cells that fail to complete the development undergo programmed cell death or apoptosis.

The B cell development begins when the stromal cells of bone marrow send signals to the lymphoid progenitor cells. The synthesis of the recombinase (RAG-2 and RAG-1) and TdT in CD34+ lymphoid progenitors is induced by the cytokines. The cells present on the H chain chromosome undergo D-J joining to become early pro-B cells. The expression of Class II MHC and CD45 (B220) also begins. The late pro-B cell stage is completed when the V segment is joined to the D-JH.

Pro-B cells transform into pre-B cells when chains are expressed by them with surrogate light chains present in the pre-B receptor. The pre-B receptor complex also contains signal transduction molecules. An antigen-binding signal is transmitted by the cytoplasmic tails of Ig heavy chains because they are very short to enter the cytoplasm. signal transduction molecules contain Immunoreceptor Tyrosine Activation Motifs (ITAMs) which phosphorylates due to the antigen-BCR binding. A cytoplasmic signaling cascade is initiated due to phosphorylation. The recombination of the H chain is stopped by the cell and it proliferates into a clone of B cells and all produce the same chains. This stage is called the large pre-B cell because resting cells are smaller than dividing cells.

After proliferation, small pre-B cells that are not dividing anymore undergo V-J joining on one L chain chromosome. The cell is known as an immature B cell when L chain is completely synthesized and expressed with chains present on the cell membrane. Immature B cells die in the bone marrow when it binds with the self antigen because they are extremely sensitive to antigen binding. Those B cells that are unable to bind self antigen are able to express chain and membrane IgD with their IgM when they are leaving the marrow and becoming mature naive B cells.

The defense provided by the B cells is known as antibody-mediated immunity because the activated B cells become plasma cells that form antibodies. It is also known as humoral immunity because the antibodies are found in the lymph or blood.

The B cells activate in the spleen or a lymph node when the specific antigen binds to its specific B-cell receptor (BCR). Thus, the activation is the process by which B cells get activated to produce its clones once the specific antigen binds to its BCR.

The B cells undergo clonal expansion and divide by mitosis several times soon after antigen binds to its BCR. B cells form many copies of itself and most of the clones transform into or become plasma cells, that circulate in the lymph and the blood. The plasma cells are greater than regular B cells because of the presence of an extensive network of RER (rough endoplasmic reticulum) for the production and secretion of the antibodies to a particular antigen on a larger scale.

Few cloned cells are transformed into memory cells which are critically important for long-term immunity. The second exposure of any antigen results in the quick division of the memory B cells that further give rise to more plasma cells that have the ability to produce the correct antibody rapidly.

The clonal selection theory explains the binding of the antigen with its specific receptor of only one type of T cell or B cell and then that T cell or B cell divides rapidly forming its clones.

The formation of the new plasma cells is ceased when the threat of the infection is passed. The already existing plasma cells undergo a cascade of particular cellular events and results in the destruction and death of the cell by the process of apoptosis.


Related Solutions

Please answer the below question in detail with great examples. In most organizations, HR is only...
Please answer the below question in detail with great examples. In most organizations, HR is only brought in for informative consultation after the strategic plan is constructed to ensure that the HR team will be able to provide the right number of people, in the right place, with the right training. Such a process is too little, too late and ignores the values which HR can provide to the strategic planning process. What values does HR provide to the strategic...
Please use this paper to answer both the sub section question in detail please. this paper...
Please use this paper to answer both the sub section question in detail please. this paper is avialbale online so thier is no plagirism http://genesdev.cshlp.org/content/9/7/783.full.pdf Q. It is mentioned that embryos produced by the cactSu/ cactSu females are fully viable, yet when injected with the cactΔPEST mRNA, they become dorsalized, sometimes quite strongly (Fig. 6B). Propose why this dorsalization would happen in these injected embryos.
Please use this paper to answer both the sub section question in detail please. this paper...
Please use this paper to answer both the sub section question in detail please. this paper is avialbale online so thier is no plagirism http://genesdev.cshlp.org/content/9/7/783.full.pdf Q. How did the use of the cactSu and cactΔPEST versions of cactus helped to demonstrate the existence of two types of degradation that control the levels of Cactus protein.
Please use this paper to answer both the sub section question in detail please. this paper...
Please use this paper to answer both the sub section question in detail please. this paper is avialbale online so thier is no plagirism http://genesdev.cshlp.org/content/9/7/783.full.pdf 1. a: What does the presence of the Cactus protein band in the “15’ “ lanes in extracts from theToll-,tube -, and pelle-mutants (Fig. 1B) indicate? Please help in detail. 1. B: What is the top band in Figs. 1A and 1B (and other Western blots) and how did the researchers use it to their...
Please use this paper to answer both the sub section question in detail please. this paper...
Please use this paper to answer both the sub section question in detail please. this paper is avialbale online so thier is no plagirism http://genesdev.cshlp.org/content/9/7/783.full.pdf Q. What is cactSu? How was it discovered and what is the molecular change (in general terms) in CactSu comparing to the normal version of maternal Cactus?
This case is based entirely on hypothetical information –please use only the information in the case...
This case is based entirely on hypothetical information –please use only the information in the case and do not use any information about the products/brands through other sources. Ensure that you study Chapter 2 of the textbook for the BCG Growth Share Matrix and Diversification Analysis/Market Product strategies and Matrix. Please do internet based research to understand the concepts of Harvest, Invest, and Divest) The firm Johnson-Evinrude Inc (or JE, to keep it short) has been in existence for more...
Hi. I needs only Conclusion and Bibliography for the information below please. Subject Name: PROJECT PLANNING,...
Hi. I needs only Conclusion and Bibliography for the information below please. Subject Name: PROJECT PLANNING, MANAGEMENT AND COSTING EXECUTIVE SUMMARY INTRODUCTION PROJECT ASSESSMENT CONCLUSION APPENDICES Scope: Produce A Family Home; Have Innovative Design; Create A Welcoming Environment; Have The Home Blend Into Its Surroundings; Have Little To No Environmental Impact; PROJECT TYPE Home Build – Turnkey Project Turnkey Solution To Client; Engineering Solutions; Engage Master Builder; Liaise With Council Regulations; Produce Architectural Design And Models; Land Acquisition; Land Development,...
Question explain in detail: Explain alternation of generations in the life cycle of an organism. Use...
Question explain in detail: Explain alternation of generations in the life cycle of an organism. Use an example from the plant kingdom and discuss how that group of plants (Gymnosperm, Angiosperm, etc.) accomplishes reproduction by alternation of generations.
Please explain these in detail - at least a paragraph or two for each question. 1....
Please explain these in detail - at least a paragraph or two for each question. 1. Explain each term: supercomputing, grid computing, and cluster computing 2. What are the differences between supercomputing, grid computing, and cluster computing? 3. How are these phenomena empowered by Moore’s Law?
What is a SWOT analysis? Explain in detail and give examples. NO HANDWRITING PLEASE Only typed...
What is a SWOT analysis? Explain in detail and give examples. NO HANDWRITING PLEASE Only typed answers
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT