Skip to main content

Type 2 ( Antibody Mediated ) Hypersensitivity Reaction-Mechanism-Diseases and Examples

Type 2 ( Antibody Mediated ) Hypersensitivity Reaction-Mechanism-Diseases and Examples
•Type 2 hypersensitivity reaction is mediated by antibodies directed against the Antigens (intrinsic or extrinsic and normal or altered) present on the cell surface or extracellular matrix.

MECHANISM OF TYPE II (ANTIBODY MEDIATED) HYPERSENSITIVITY

There are three mechanisms of type two hypersensitivity reactions. Each Mechanism gives rise to different clinical manifestation.Type 2 hypersensitivity Reaction image

•1)- Opsonization of cells by antibodies and complement components and ingestion by phagocytes.

In this mechanism, antibodies are formed against antigens present on the cell surface. Antibodies opsonize the antigens for phagocytosis. Moreover, these Antibodies also stimulate the complement system which further opsonizes the cells for phagocytosis). Opsonization is a process in which antibodies combine with antigens and which are then recognized by the phagocytes for phagocytosis.

•2)- Inflammation induced by antibodies binding to Fc receptors of leukocytes and by complement breakdown products.

In this mechanism, The Antibodies attach to the cell surface Antigens through fab component while at the same time to Fc receptors of leukocytes through the Fc component. The leukocytes are thus stimulated and release injurious substances like enzymes and reactive O2 species resulting in damage to tissues. The antibodies also stimulate the complement factors producing C5a (chemotactic factor) attracting more leukocytes towards the site of injury/damage.

•3)- Anti- receptor Abs disturb the function of the receptors:

In this mechanism, Antibodies are formed against the cell surface receptors (which are considered as antigens) specific for some other hormone, neurotransmitter etc and impair their function either by stimulating them or blocking them.

Examples Of Type two Hypersensitivity Reactions and Diseases;

Diseases of mechanism 1:

Transfusion reactions, Erythroblastosis fetalis, Autoimmune Hemolytic Anemia,  Idiopathic Thrombocytopenic Purpura (ITP)

Diseases of mechanism 2:

Good pasture Syndrome (Nephritis and Lung haemorrhage), Rejection of transplant, Rheumatic Fever

Diseases of mechanism 3:

Myasthenia Gravis, Graves Disease, Pernicious Anemia, insulin resistant D.M, Pemphigus Vulgaris.
Labels:

Comments

Post a Comment

Post Your Reply and Give Your Opinion About the Post

Popular posts from this blog

Human Parasites, Types of Parasites, and Classification

Parasite: A parasite is a living organism which gets nutrition and protection from another organism where it lives. Parasites enter into the human body through mouth, skin and genitalia. In this article, we will generally discuss the types and classification of parasites. It is important from an academic point of view. Those parasites are harmful, which derives their nutrition and other benefits from the host and host get nothing in return but suffers from some injury. Types of Parasites Ecto-parasite: An ectoparasite lives outside on the surface of the body of the host. Endo-parasite: An endo-parasite lives inside the body of the host, it lives in the blood, tissues, body cavities, digestive tract or other organs. Temporary parasite: A temporary parasite visits its host for a short period of time. Permanent parasite: Permanent parasite lives its whole life in the host. Facultative parasite: A facultative parasite can live both independently and dependently. It lives in the...
Post a Comment
Read more.>>

IELTS or OET - Reviews - Personal Experience - Which to Choose - IETLS vs OET

OET and IELTS both are used to assess the knowledge of English Language. The basic difference between the above two is this, IETLS is a more generalized English language assessment test, on the other hand, OET is profession specific. For example, if you are a doctor, the content of the test will be related to your occupation. Because of this, the OET is being chosen by many healthcare professional instead of IELTS. Both tests have the same sub-categories, that is listening, speaking, writing and reading. Lets us discuss the differences one by one. TEST OET IELTS OET Compared to IELTS is ………. (Author’s opinion) Speaking You will need to do two role plays. You will be given a situation and asked to counsel the patient about a disease and treatment or break the bad news. It has 3 parts, first is an introduction and general question, In the second part you will be provided with a topic to speak for 2 minutes. In the 3rd part, you will b...
Post a Comment
Read more.>>