Type IV hypersensitivity reaction result from inappropriate T-cell activation. It takes at least 3 days to develop its action for this reason it is also called delayed type hypersensitivity (DTH). It is the only hypersensitivity category, that is purely cell mediated rather than antibody mediated. Mentioned disorders: Contact dermatitis, Chronic transplant rejection, Multiple sclerosis, Granuloma …

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In type III hypersensitivity reaction, antigen-antibody complex deposited on host cells induces complement fixation and enhance inflammatory reaction. It is mainly mediated by Ig-G antibodies complement protein and neutrophils. The reaction of antibodies with the soluble antigens, generates immune complexes. Generally, these reactions facilitate the clearance of antigens by phagocytes But some times the presence …

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Type II hypersensitivity reactions is also an autoimmune disease involve antibody-mediated destruction of cells by immunoglobulins of heavy chain classes other than Ig-E. The reaction occurred by binding of Ig-G or Ig-M antibodies to the antigen expressed on the surface of the host cells, which are then destroyed by complement or cell-mediated mechanism. It is …

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Type I hypersensitivity is an immediate anaphylactic reaction associated with allergy. These reactions are mediate by Ig-E antibodies and includes many of the most common allergies to respiratory allergens, such as pollen, dust mites etc. The mast cells and basophil, also participate in this reaction. Type I Hypersensitivity is also known as immediate or allergic …

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The same immune reaction which protects us from infection can also inflict a great damage not only to the pathogen but also our own body cells and tissues. The immune response uses multiple strategies to reduces the damage. If there is any break down of checks and balances of immune response then it is leading …

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Both B-cell and T-cell use surface molecules to recognize antigen, they fulfill this in very different ways. B-cell receptor or antibodies can recognize an antigen alone but T-cell receptor only can recognize pieces of antigen, bound with the surface molecule of other cells. These antigen pieces are attached with the binding groove of a cell …

Major histocompatibility complex note Read More »

The process through which our body’s immunity increased against a particular pathogen (organism which form the disease) or antigen, is known as immunization. Immunity can be acquired or can be gained by natural process. Immunization is mainly two types-Passive immunization and Active immunization. These are done by many different ways. One of the most successful process …

What is vaccination and it’s principle Read More »

Microvilli and it’s role in absorption is a very important topic specially for zoology student. Most of the cells have a variety of protrusions or extensions on their surface area which involved in various purpose like phagocytosis, cell movements, and in some specialized functions such as absorption of nutrient materials. Microvilli (singularly microvillus) are one of …

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