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10

Usually an antibody test against HIV is positive three month after the infection. Before this time a test can only be done with molecular biology methods as PCR. However, it is possible, that patients which have definitely been tested in an early phase using molecular biology methods and which afterwards receive a antiretroviral therapy (ART) that these ...


7

No, they are of course not there to cause allergies. It is thought (although not directly proven in human) that IgE is important to fight parasites and worms. They bind to antigens from the parasites, which leads to the secretion of histamines. This causes a local immune reaction (which also is a problem in allergies) which is helpful to fight the parasites. ...


6

I worked for a long time at a leading high-quality antibody company, so I'll try and share some of my experiences with you. The process of making a highly specific antibody (I'll focus on monoclonals) has three important parts - antigen design and immunization, cloning and subcloning, and screening/validation. Each part is crucial on its own, and the better ...


6

Maybe WB is easier for them to test? In general, however, my recommendation is to check if they provide refs to paper using those antibodies and look at the images on the paper. Be careful putting your trust in the supplier's pictures, I have seen obviously photoshopped images on commercial websites. Also always double-check the referenced papers, as ...


5

The key feature of type O blood as "universal donor" is that the incoming red blood cells have neither A nor B antigens and so the resident antibodies (anti-A , anti-B) will not react with them. Since transfusions are carried out with packed red blood cells the plasma antibodies of the donor don't matter - they will not be introduced into the recipient.


5

Making antibodies is mostly nothing you do with transgenic microorganisms. To make an antibody you first have to immunize an animal with the correct antigen. This includes have an animal facility where you can keep animals under clean conditions. If you are looking for polyclonal antibodies (meaning a whole bunch of different antibodies with different ...


5

Most IgGs should be fine when stored in the freezer. Freezing at -20 or -80 in small aliquots is the optimal storage condition. Ali-quoting minimizes damage due to freezing and thawing, as well as contamination introduced by pipetting from a single vial multiple times. Aliquots are to be frozen and thawed once, with any remainder kept at 4 ...


4

It is! Here is an amazing review from 2011 that literally has all the answers. I'm not kidding, all of them. I would marry this review if I could.1 It also includes information on other animals. The main takeaway is that IgA from milk is not readily absorbed by the infant body. Secreted IgA is mainly to provide a protective coating for the mucosa while ...


4

It happens, but it is very rare. Anti-A and Anti-B antibodies are IgM type. They do no cross the placenta. Sometimes IgG can be produced and lead to the hemolytic disease of the newborn. Anti-D antibodies are IgG type and can pass through the placenta.


4

Lets define the nomenclature first: An antigen is a large structure (protein, virus, bacteria and so an) which is recognized by the immune system as foreign. The word antigen derives from the abbreviation ANTIbody GENerator. Exposure of our immune system to an antigen results in an immune response and the generation of many antibodies. An epitope is a small ...


4

For the generation of Fab-fragments antibodies, (possibly genetically modified) which can be made in large quantities by cells or animals, are used. Antibodies as a whole are not synthesized. The Fab fragment is obtained from antibodies using the enzyme papain, which cleaves the antibody over the disulfide bonds in the hinge region. This results in two Fab ...


4

You don't specify which temperature of freezer you're talking about. Antibody can be stored at -80 for long time, but needs to avoid freeze and thaw process. Some people store aliquot of antibody in -80. Another way is to dilute antibody in Glycerol, make 50% dilution. You need to mix well, and then store at -20.


3

If you have an antibody that is directed against, for example, a bacterial surface protein, then by mixing the bacterial cells with the antibody at a suitable stoichiometry you could observe clumping of the cells as the antibody molecules essentially cross link the cells together. This would be an example of using an agglutination (clumping) assay with a ...


3

Within an organism, antibodies which bind to other antibodies in the body would be eliminated during clonal selection. They are not made by the body after that period, which is in the first few months of life. Such antibodies would have to be introduced from the outside. Many have been designed or engineered for biotech and as therapeutics.


3

Immunopanning is essentially an immunoprecipitation (IP) of cells using an antibody immobilized to a solid surface, like a cell culture plate. Conventionally, an IP is performed using small agarose or magnetic beads (~50 to 150μm in size) conjugated to an antibody or Protein A/G, and can pull down individual proteins, protein complexes, and/or nucleic acid ...


3

When testing an antibody for an imaging application, it is almost always a good idea to test it in another application like ELISA or Western blotting to see if it binds the target of interest. For example, try to find high- and low-expressing cell lines, load equal amounts, and see if there is a difference in signal at the expected molecular weight. Check ...


3

The processes are called gene rearrangement and somatic hypermutation, and are used by maturing B-cells to generate very (very) large amounts of diversity in the antibody repertoire. If your institution has access, this great article in Annual Reviews in Immunology has all the details, or you can read about it in Janeway (slightly outdated edition). ...


3

I'll preface this by saying that I'm talking about antibodies of mammalian/human origin, consisting of two identical heavy and two identical light chains disulfide-bonded into the classic antibody structure: It is possible to produce antibody-like molecules known as single-chain antibodies, including single-chain variable fragments (scFv) in bacteria and ...


3

I don't believe that the Isotype Control Antibody makes the antibody bind more specifically but rather ensures that your signal is specific to your antibody. The Isotype Control Antibodies tend to bind to the non-binding domain of the antibody, typically the constant (Fc) domain. By measuring the concentration of the control antibody, you can determine what ...


3

Antibodies are simply proteins and like any other protein have a relatively short "life", so after clearing out an infection, they are not retained for long (most of them anyway). What the body keeps is memory cells which can produce a much more rapid response if they come in contact with the same pathogen again. You could see it as a selective process: the ...


3

The confusion that you're facing is because RAP-5 is actually known as RAB5C (GENEID). The ras superfamily (review) is divided into Ras, Rho, Rab, and Rap. But the Rap GTPases are divided only into two categories, RAP1 and RAP2. On the other hand, there are multiple Rab GTPases which include RAB5A and RAB5C. There are a few crystal structures of both Rab5A ...


3

Antibodies for WB and for IF have fundamentally different requirements for the epitope structure. Antibodies for WB recognize denatured structures extended by SDS treatment. Antibodies for IF often will need to recognize a native-like structure. Depending on the supplier, some will have lots of antibodies for IF. I suggest looking around some more.


3

ELISA is Enzyme-Linked ImmunoSorbent Assay (capitalisation to point out source of acronym). You can read about the various ways to do an ELISA here. In your case this was probably an indirect ELISA. All ELISA techniques make use of the fact that proteins stick to plastic. In your case the protein components of the saliva, including the virus (the viral ...


3

When the radial immunodiffusion method is used to measure antigen concentrations in samples, a plate or slide is set up using agarose containing an antibody or antiserum. Holes are punched out of the agarose to form wells into which antigen is dispensed. The antigen diffuses out into the agarose and when the antigen/antibody ratio is favourable an ...


3

It's common for the human immune system to create antibodies against many proteins, even some human proteins. Hemophiliacs who receive regular doses of clotting factor proteins often develop neutralizing antibodies against the clotting factor proteins, even though they are a human protein1. Therefore it's not surprising that antibodies would be developed ...


3

What you can do depends on your proteins: If both proteins (your target protein and the loading control) are seperated far enough, you can detect both of them in the same step by adding both primary antibodies and both secondary ABs into the buffer at the same time. They will bind only to their specific epitope and you will get nice signals. This is ...


3

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 ...


2

While bobthejoe/leonardo's answers are correct, you also need to be aware of the quality and limitations of isotype controls. You need to pick your source very carefully, as extensive testing (at my former company) has shown that some isotypes stick non-specifically under certain conditions or with certain samples. For example, we found that one common ...


2

The short answer is that antibodies are proteins like any other, and if an antibody from a foreign source is injected it can result in an immune response. This is, of course, exploited in the production of secondary antibodies for use in research (e.g. goat anti-rabbit IgG is a goat antibody that recognises rabbit IgG). Because of this, therapeutic ...


2

Like any other protein, antibodies will aspecifically bind nitrocellulose or PVDF membranes, but any other protein present in your antibody preparation will also do. Depending on the antibody class, more specific binding can be obtained with protein A or protein G, that recognize the Fc domain. It's usual to have protein A/G immobilized on a stationary ...



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