immunity

SOUNDARYA .V I BDS 2009-2010

Is defined as the capacity of the body to resist the pathogenic agents.

Ability of the body to resist the entry of different foreign substances like bacteria, virus , toxic substances.

Precursors in the bone marrow.

During fetal development.

Released into circulation.

T - Lymphocytes and B- Lymphocytes.

Produced in the thymus .Formation during period between

birth and few months after birth .Thymosin – hormone.60-80% of the circulating

lymphocytes.Cell-mediated immunity.Receptors are present on the

surface.

75% of T-cells.

Form a series of a protein mediators called LYMPHOKINES.

Stimulation & growth of killer cells.

Feedback stimulation of other helper cells.

Activation of macrophages system.

Kill and attack the micro-organisms.

Are activated by the helper T –cells.

Have receptors present on the membrane which bind to the antigens.

Cells release a lysosomal enzyme which punctures holes on the antigens.

Suppresses the functions of both the cytotoxic and helper cells .

Prevent excessive immune reactions that may harm the body.

Memory cells identify the organism for the second time and activate the other T –cells.

20-25 %.Short life span.Bone marrow.Plasma cell & Memory cells.Humoral immunity.

10-15%Third type – non T , non-B cells.Hydrolytic enzymes - lysis

FUNCTIONS :Destroy malignant cells.Attack viruses.

Substances that induce specific immune reactions.

Antigenicity- more molecular weight, more antigenic.

Proteins / Polysaccharides, complex lipids.

ANTIGENS: Auto antigensForeign antigens

Produced due to antigenic stimulus and react specifically with it.

Formerly known as gamma globulins.

All antibodies are Immunoglobulin and all immunoglobulin are not antibodies

STRUCTURE:

Y-shaped. Light chains. Heavy chains. Linked by di -Sulphide

bonds. Variable & Constant

region.

Direct action:Agglutination, Precipitation, Neutralization &Lysis

Complement system:Classical pathway-o C1 binds with antibodies

Alternate pathway-o Due to protein in circulation calledo FACTOR 1.o Activates C3 and C5 .

Insulin Dependent Diabetes Mellitus.Myasthenia Gravis .Grave’s Disease.Rheumatoid Arthritis.