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I found some reports on it (like reference 1) but there is an oddly little amount of publications on this topic. then I found this review in Mucosal Immunology (reference 2, interesting to read) which doubts this activation. It says: Interaction with complement IgA lacks the residues identified in the Fc regions of IgG or IgM that bind to C1q, and ...


6

First: What your teacher says about the free floating antibodies is not correct. The first contact with a new antigen to generate specific immunity is done by naive B cells which have a membrane bound B cell receptor and their effector T cells. This contact can either happen directly or by the presentation of the antigen to the cell by antigen presenting ...


6

First: B cells do not produce antibodies, but rather they synthesise the B cell receptor. This may sound a bit picky, but is not, since the B cell receptor is anchored in the membrane of B cells and not secreted. Its this receptor which recognizes antigens and causes the production of highly specific antibodies (including somatic hypermutation and all ...


4

The short answer seems to be that fevers help combat microbes (a term I take herein to include viruses for brevity), which aren't a part of the threat addressed in an allergic reaction. While there's not a full consensus on which benefits, if any, a fever brings to the response to microbes, both humans and other warm-blooded vertebrates fare better with ...


3

Preamble From the point of view of understanding I think it is better to talk about the constant and variable regions of antibodies, rather than Fab and Fc, as these are historical designations for fragments of the molecules that were useful in research, but do not exist as separate entities. Cartoon representation It is possible to represent the ...


3

If the sequence of the 26 kDa form is included within the sequence of the 28 kDa form then the answer is 'probably yes'. However if the N- or C-terminus of the short form is an important/dominant epitope and it is masked in the long form (by being extended) then the activity of the serum against the long form could be significantly reduced.


3

To address your question about antibodies, produced by antigen-specific B cells or plasma cells, I'm first going to address how you activate a B cell. Naive B cells are produced in the bone marrow with antigen specificity encoded in it's B cell receptor (BCR), a product of VDJ recombination. Each B cell has a specificity toward a single antigen through it's ...


3

When the Naive B cell gets activated and begins to secrete antibodies the affinity of the antibodies is low, as it hasn't yet gone through several cycles of affinity maturation. The increased avidity of the IgM balances the decreased affinity of these initial antibodies. If IgG were released at this stage, the body would have a much lower immune reaction to ...


3

You are correct. In an IgG antibody, there are a total of four protein chains — two identical heavy chains, and two identical light chains, each heavy pairing with a light to form one of the two "arms" of the molecule. Each heavy chain has three CDR regions — H1, H2, and H3 — as do each light chain (L1, L2, and L3). When the full molecule ...


2

Cancer is uncontrolled division of abnormal cells. This is caused by mutations in a cell which causes a cell to divide more frequently and the lack of control by intracellular AND extracellular mechanisms. The extracellular mechanisms include growth inhibition by hormones, local factors, contact and also the immune system. These cancerous cells could be ...


2

Short Answer : B-cells class switch to become Plasma cells in the germinal centre of the lymph node. Long Answer : There are two important concepts addressed in the question. One is the Immunoglobulin structure - isotype and membrane/soluble type. And the other is the germinal centre B-cell paradigm. Understanding both the concepts are a prerequisite to ...


2

"In order to trigger the specific immune response of the body, antibodies must first attach to the pathogen" - This is wrong. Either you misunderstood, or the teacher was mistaken. Specific immunity is triggered with no need for antibodies to bind to the pathogen. Very simplistically, the earliest stages in specific immune responses require T cells and ...


1

Naive T cells hang out in the lymph node waiting for antigen presenting cells (APCs) like DCs to present processed antigens on their MHC molecules. Naive B cells similarly hang out in the B cell zone and are capable of interacting with other T cells and follicular dendritic cells (FDCs). Antigen that ends up in the lymph ends up traveling to the lymph node, ...


1

This is a wonderful question, because it addresses a common misunderstanding. Short Answer: We have no clear data about the effectiveness of a one single antibody molecule in the immune response of an entire organism, but since many different antibodies can recognize the same pathogen, and . Just as antibodies in a healthy individual are able to find, bind ...


1

Antibodies are produced after exposure to cognate antigen. Remember that B cells start off expressing membrane IgM and/or IgD. IgA requires class switching recombination at the B-cell receptor locus to the IgA isotype. Further differentiation of the B cells to antibody-secreting plasma cells results in soluble IgA production and immunologic memory to the ...


1

This is completely dependent on the type of antibody you are using and the epitope specificity of that antibody (or antibodies). Because you haven't given any more detail, it's very hard to give you a definitive answer. GST is known to dimerise, so even a monoclonal antibody might work in your sandwich assay, as long as the (identical) epitopes are far ...


1

Since people and animals routinely get sick, it is obvious that our immune system (which includes but isn't limited to antibodies) doesn't always protect against pathogens. There are many reasons for this, far too many to summarize here, but one common reason is that it takes several days for the adaptive part of the immune system (which includes antibodies,...


1

As @canadianer mentions in his comment, Protein G is more than likely named after the human group G strain of Streptococci, G148. Protein G, a bacterial cell wall protein with affinity for immunoglobulin G (IgG), has been isolated from a human group G streptococcal strain (G148). Purification and some properties of streptococcal protein G, a novel IgG-...


1

Excerpt from Cellular and Molecular Immunology, 8th ED, p.181-182. Don't up-vote me, i just thought this text offers a good, up-to-date explanation. The Mechanism of V(D)J Recombination Rearrangement of Ig and TCR genes represents a special kind of non-homologous DNA recombination event, mediated by the coordinated activities of several enzymes,...


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