Natural killer cell

Natural killer cells (NK) : are a type of lymphocyte :  innate immune system.

NK cells play a major role in the host-rejection of both tumours and virally infected cells.

NK cells are cytotoxic; small granules in their cytoplasm contain special proteins such as perforin and proteases known as granzymes.

:  release in close  to a cell for killing, perforin forms pores in the cell membrane of the target cell : the granzymes  can enter and  apoptosis.

NK  are activated in response to interferons or macrophage-derived cytokines.

Patients deficient in NK cells prove to be highly susceptible to early phases of herpes virus infection.

Natural killer cell deficiency

:inherited immune system disorder, patient has low or absent levels of a certain type of NK cells.

: five different genes have been shown to cause NK cell deficiency. Each of these genes is passed down as an autosomal recessive trait. 

these patients are vulnerable to infections. 

suffer from frequent infections, especially lung infections and herpes virus infections

Life expectancy :depending on how severe the deficiency.

The condition may lead to fatal infections and  increased of developing cancer.

Diagnosis:

DNA analysis

Natural killer cell count

Treatment:

no specific treatment for natural killer (NK) cell deficiency. Treatment focuses on curing infections associated with the disorder.

HYPERSENSITIVITY REACTIONS

HYPERSENSITIVITY REACTIONS 

 Refers to excessive, undesirable reactions produced by the normal immune system. 

Four types: type I, type II, type III and type IV.

Type I:

immediate or anaphylactic hypersensitivity.

:mediated by  IgE.

The reaction may involve skin,eye, nasopharynx , bronchopulmonary tissues ,gastrointestinal tract.

 The primary cellular component is the mast cell or basophil. 

The reaction is modified by platelets, neutrophils and eosinophils.(mainly mast cells and eosinophils)

The mechanism of reaction:produce IgE, in response to certain allergens.

Reason: individuals produce more of TH2 cells that secrete IL-4, IL-5 and IL-13 which in turn favor IgE class switch. IgE has very high affinity for its receptor (Fcε; CD23) on mast cells and basophils.

A subsequent exposure to the same allergen cross links the cell-bound IgE and triggers the release of various pharmacologically active substances . Cross-linking of IgE Fc-receptor is important in mast cell triggering. Mast cell degranulation is preceded by increased Ca++ influx, which is a crucial process; ionophores which increase cytoplasmic Ca⁺⁺also promote degranulation.

I think I have a type 1 hypersensitivity, because when I eggplant, tomato sauce, pepper , all of my body is itching.    

C1 -inhibitor

:is a protease family belonging to the serpin super family.

C1-inhibitor has a 2-domain structure. The C-terminal serpin domain is similar to other serpins, which is the part of C1-inhibitor that provides the inhibitory activity. The N-terminal domain is not essential for C1-inhibitor to inhibit proteases. 

 main function : inhibition of the complement system to prevent spontaneous activation.

 : C1-inhibitor irreversibly binds to and inactivates C1r and C1s proteases in the C1 complex of classical pathway of complement.

 C1-inhibitor also inhibits proteases of the fibrinolytic, clotting, and kinin pathways. 

 Hereditary angioedema

Deficiency of this protein is associated with hereditary angioedema(HAE).

This problem affects the blood vessels. People with hereditary angioedema can develop rapid swelling of the hands, feet, limbs, face, intestinal tract, larynx.

Factor H

 is a member of the regulators of complement activation family and is a complement control protein.

main function:  is to regulate the alternative pathway of the complement system.

:by possessing both cofactor activity for the factor I mediated C3b cleavage, and decay accelerating activity against the alternative pathway C3-convertase, C3bBb.

it binds to glycosaminoglycans (GAGs) that are generally present on host cells but not, normally, on pathogen surfaces.

Multiple Sclerosis

Multiple Sclerosis (MS)

The nerves of the brain and spinal cord are damaged by one's own immune system.(autoimmune disease)

The immune system attacks the brain and spinal cord, 

the two components of the central nervous system.

:loss of muscle control, vision, balance, and sensation.

The nerves of the brain and spinal cord are damaged by one's own immune system.(autoimmune disease)

The central nervous system is made up of nerves that act as the body's messenger system. Each nerve is covered by a fatty substance called myelin, which insulates the nerves and helps in the transmission of nerve impulses, or messages, between the brain and other parts of the body. These messages control muscle movements, such as walking and talking.

MS gets its name from the buildup of scar tissue (sclerosis) in the brain and/or spinal cord. The scar tissue or plaques form when the protective and insulating myelin covering the nerves is destroyed, a process called demyelination. 

Without the myelin, electrical signals transmitted throughout the brain and spinal cord are disrupted or halted. The brain then becomes unable to send and to receive messages.