How does agglutination happen

Agglutination in all three test tubes indicates that all three antigens are present in the blood: A, B and Rh. Agglutination in the test tubes containg A antibodies and B antibodies. Accordingly, the blood type is AB Rh-.

Agglutination in the test tube with Rh antibodies indicates that the blood has got Rh antigens but no A nor B antigens. The blood will agglutinate if the antigens in the patient's blood match the antibodies in the test tube. A antibodies attach to A antigens - they match like a lock and key - and thus form a clump of red blood cells.

In the same way B antibodies attach to B antigens and Rh antibodies to Rh antigens. In the test tubes where agglutination has occured, the patient's red blood cells have been linked together, like bunches of grapes, instead of floating around one by one. Disclaimer: The fact that people with Rh- blood do not naturally have Rh antibodies in the blood plasma as one can have A or B antibodies, for instance is not taken into consideration in this game.

Examine the slides below and determine the blood type of the subject in each case. Click below to check your answer. When transfusing blood, it is important to remember that the donor's blood must not contain red blood cells that the recipient's antibodies can agglutinate.

Theoretically, then, individuals belonging to blood group O are universal donors, while those of blood group AB are universal recipients. T he Rh System Rh antigens, named for the rhesus monkey in which they were first discovered, are also surface antigens expressed on red blood cells.

There are a few Rh antigens common one is called D. Red cells expressing the Rh antigens are called Rh positive. For example, influenza viruses have two different types of viral spikes called neuraminidase N and hemagglutinin H , the latter named for its ability to agglutinate red blood cells see Viruses.

Thus, we can use red blood cells to detect the presence of influenza virus by direct hemagglutination assays HA , in which the virus causes visible agglutination of red blood cells. The mumps and rubella viruses can also be detected using HA. Most frequently, a serial dilution viral agglutination assay is used to measure the titer or estimate the amount of virus produced in cell culture or for vaccine production.

A viral titer can be determined using a direct HA by making a serial dilution of the sample containing the virus, starting with a high concentration of sample that is then diluted in a series of wells.

The highest dilution producing visible agglutination is the titer. The assay is carried out in a microtiter plate with V- or round-bottomed wells. In the presence of agglutinating viruses, the red blood cells and virus clump together and produce a diffuse mat over the bottom of the well.

In the absence of virus, the red blood cells roll or sediment to the bottom of the well and form a dense pellet, which is why flat-bottomed wells cannot be used Figure 5. Figure 5. A viral suspension is mixed with a standardized amount of red blood cells.

No agglutination of red blood cells is visible when the virus is absent, and the cells form a compact pellet at the bottom of the well. In the presence of virus, a diffuse pink precipitate forms in the well.

A modification of the HA assay can be used to determine the titer of antiviral antibodies. In this assay, patient serum is mixed with a standardized amount of virus. After a short incubation, a standardized amount of red blood cells is added and hemagglutination is observed. Figure 6. In this HIA, serum containing antibodies to influenzavirus underwent serial two-fold dilutions in a microtiter plate.

Red blood cells were then added to the wells. Agglutination only occurred in those wells where the antibodies were too dilute to neutralize the virus. In the case of this test, Sample A shows a titer of , and Sample C shows a titer of Much of what we know today about the human immune system has been learned through research conducted using animals—primarily, mammals—as models.

Besides research, mammals are also used for the production of most of the antibodies and other immune system components needed for immunodiagnostics.

Vaccines, diagnostics, therapies, and translational medicine in general have all been developed through research with animal models. Consider some of the common uses of laboratory animals for producing immune system components. Guinea pigs are used as a source of complement, and mice are the primary source of cells for making mAbs.

These mAbs can be used in research and for therapeutic purposes. Antisera are raised in a variety of species, including horses, sheep, goats, and rabbits. When producing an antiserum, the animal will usually be injected at least twice, and adjuvants may be used to boost the antibody response.

The larger animals used for making antisera will have blood harvested repeatedly over long periods of time, with little harm to the animals, but that is not usually the case for rabbits. Although we can obtain a few milliliters of blood from the ear veins of rabbits, we usually need larger volumes, which results in the deaths of the animals. We also use animals for the study of disease.

The only way to grow Treponema pallidum for the study of syphilis is in living animals. Many viruses can be grown in cell culture, but growth in cell culture tells us very little about how the immune system will respond to the virus. Studying the proliferation of bacteria and viruses in animal hosts, and how the host immune system responds, has been central to microbiological research for well over years.

While the practice of using laboratory animals is essential to scientific research and medical diagnostics, many people strongly object to the exploitation of animals for human benefit.

Most scientists acknowledge that there should be limits on the extent to which animals can be exploited for research purposes. Ethical considerations have led the National Institutes of Health NIH to develop strict regulations on the types of research that may be performed.

These regulations also include guidelines for the humane treatment of lab animals, setting standards for their housing, care, and euthanization. Read what you need to know about our industry portal bionity. My watch list my. My watch list My saved searches My saved topics My newsletter Register free of charge. Keep logged in. Cookies deactivated. To use all functions of this page, please activate cookies in your browser. Login Register. Additional recommended knowledge.

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