Immunity

Facebook Tweet Email LinkedIn Print

The mechanism used by the body as protection against environmental agents that foreign to the body. Immunity is a state of protection against foreign pathogens or substances (antigens).

It responds to threats on an individual basis.

Term immunity derived from – Immunis, meaning Exempt.

Immune system is remarkably versatile defense system that has evolved to protect animals from invading pathogenic microorganisms and cancer.

Types of Immunity:

Innate immunity: primitive immune system which is less specific
Adaptive immunity: highly evolved system of specific response

Innate Immunity

Also called Native
Resistance possessed by an individual by birth i.e., inherited
Provides first line of defense against infections
Genetically determined: no prior exposure or antibody production involed
3 levels:

Species immunity: entire human species is resistance to plant pathogen.

Racial immunity: particular races of that species are resistant. Example: Negroid species in USA is more prone to TB than causcian species.

Individual immunity: evident on twin – smiliar degree of resistance to TB or leprosy.

They are always present and available at short notice to protect the individual from challenges by foreign invaders
Elements of innate immune system includes body surfaces and internal components, such as: skin, the mucous membrane, cough reflex.
It is carried out by non-specific physical and chemical barriers (eg-skin), cellular barriers (eg-phagocytes) and molecular pattern based reactions (eg-toll like receptors or TLRs).
It is line of defense:

First line of defense: intact skin and mucosae prevent entry of microorganism

Second line of defense: antimicrobial proteins, phagocytes and other cells.

Factors influencing the level of innate immunity:
Age
Very old or very young, more susceptible to infectious disease.
In foetus, immune system is immature where as in old age there is gradual decrease in immune system
Hormones
Endocrine disorders such as Diabetes mellitus, Hypothyroidism, and Adrenal dysfunctions
Staphylococcal sepsis is more common in Diabetes, which may be caused by increased level of carbohydrates in tissues.
Nutrition
Immune system is reduced in malnutrition patients
In Kwashiorker ( serve protein deficiency system), cell mediated system reduces.

Acquired or adaptive Immunity

The resistance that human acquires during life
Provides second line of defence
Produces by prior exposure or antibody production
Characteristics:

Antigen specificity: immune system or antibiotics can distinguish among antigens, even between 2 proteins that differ in only 1 amino acid.

Diversity: immune system is capable of generating large antibody diversity in its recognition molecules.

Immunologic memory: immune system exhibits memory on second encounter of same antigen by generating a second response which is more specific and quick.

Self and non self recognition: does not react with body’s own molecule but effectively eliminates foreign antigens.

Types:

Active: natural active immunity and artificial active immunity

Passive: natural passive immunity and artificial passive immunity

Active immunity

also called acquired immunity
Resistance developed by an individual as a result of an antigenic stimulus.
Used for prophylaxis to increase body resistance.
Produced by antibodies that develop in response to antigens (Immune response)
Latent period: requires time for its activation.
Negative phase: a time period in which there is reduced measurable immunity – antigen combines with the pre-existing antibody and lower its circulation.
More effective and better protection than passive.

Types:

Natural active immunity:

Clinical infection by a microbe
Develops after exposure to antigens in environment
Long lasting immunity but varies on type of pathogens
Large majority of adult – active immunity against Poliovirus
Life long immunity – viral diseases like Chicken pox or Measles
Premuntion: immunity to re-infection last long till the disease remains active.
Example: Typhoid.

Artificial active immunity:

Resistance reduced by vaccines
May be either bacterial or viral vaccines
Develops after administration of antigen to prevent disease
Booster dose: repeated dose of vaccines following the primary vaccination prolong the immunity
May be either in form of:
Live immunity: initiates the infection without causing any injury and disease. It parallels with natural but of low grade. Example: BCG for tuberculosis.
Killed vaccines: comparatively less immunogenic. Protection lasts only for a short period. Have to be supplemented by booster dose repeatedly. May be given orally. Example: Cholera vaccine.
Bacterial products: example: Tetanus toxoids.

Passive Immunity

Resistance transmitted passively to a receipent in a readymade form
Produced by transfer of antibodies from another person
Receipents immune system plays no active role
Used for the treatment of acute infection

Types:

Natural passive immunity:

Conferred by transfer of maternal antibodies across placenta or in breast milk
Resistance passively transferred from mother to foetus or infants, through placenta and through milk (colostrums – IgA antibodies)
Human fetus – ability to synthesize IgM from 20^th week of life
Transport of antibodies across the placenta is an active process – concentration in fetal blood is higher than in mother blood.

Artificial passive immunity:

Resistance passively transferred to a recipient by administration of antibodies.
Conferred by administration of antibodies to combat infection
Agents used: hyperimmune sera of animal, covalescent sera, pooled human gamma globulin
These are used for psophylaxis and therapy.

iQOO Z9 5G (Brushed Green, 8GB RAM, 256GB Storage) | Dimensity 7200 5G Processor | Sony IMX882 OIS Camera | 120Hz AMOLED with 1800 nits Local Peak Brightness | 44W Charger in The Box

(963)

₹21,999.00 (as of April 13, 2024 22:53 GMT +00:00 - )

Oneplus Nord CE4 (Celadon Marble, 8GB RAM, 128GB Storage)

₹24,999.00 (as of April 13, 2024 22:53 GMT +00:00 - )

realme NARZO 70 Pro 5G (Glass Green, 8GB RAM,256GB Storage) Dimensity 7050 5G Chipset | Horizon Glass Design | Segment 1st Flagship Sony IMX890 OIS Camera

(428)

₹21,999.00 (as of April 13, 2024 22:53 GMT +00:00 - )

Samsung Galaxy M15 5G (Stone Grey,4GB RAM,128GB Storage)| 50MP Triple Cam| 6000mAh Battery| MediaTek Dimensity 6100+ | Super AMOLED Display| Add to Cart and Get Travel Adapter at No Cost

(2)

₹13,299.00 (as of April 13, 2024 22:53 GMT +00:00 - )

OnePlus 12R (Iron Gray, 8GB RAM, 256GB Storage)

(701)

₹42,999.00 (as of April 13, 2024 22:53 GMT +00:00 - )

Samsung Galaxy M15 5G (Blue Topaz,6GB RAM,128GB Storage)| 50MP Triple Cam| 6000mAh Battery| MediaTek Dimensity 6100+ | Super AMOLED Display| Add to Cart and Get Travel Adapter at No Cost

(2)

₹14,799.00 (as of April 13, 2024 22:53 GMT +00:00 - )

PARTY MIDLINKERZ Rosegold Happy Birthday Decoration Items Kit Set for Kids Girls Boy Party Fabric Net Curtain Balloons Special Decorate Balloon Set 48 Pcs With Net Curtain & Led Light | Decoration kit

(1)

₹379.00 (as of April 13, 2024 22:53 GMT +00:00 - )

OFIXO 50 Meters Food Wrapping Paper Roll - Premium Non-Stick Butter Wrapping Paper. Food Wrapping Paper, Re-heatable Non Stick Paper, Oven Safe Parchment Paper

(264)

₹199.00 (as of April 13, 2024 22:53 GMT +00:00 - )

Lux Cozi Men's Regular Fit Polo Neck Half Sleeve Solid Casual T-Shirt | Polo T-Shirt for Men

(1250)

₹319.00 (as of April 13, 2024 22:53 GMT +00:00 - )

MATSON Plastic Beads for Kids Crafts Children's Jewelry Making Kit DIY Bracelets Necklace Hairband and Rings Craft Kits Birthday for 4, 5, 6, 7-Year-Old Little Girls(DIYBeadsSet-9) Multicolor

(9)

₹399.00 (as of April 13, 2024 22:53 GMT +00:00 - )

What’s Up Gluta-Glow Gummies | Liposomal Glutathione with Vitamin C for Radiant Skin Tone | Depigmentation | Detoxification | 15 Days | Men & Women | No Added Sugar

(19)

₹699.00 (as of April 13, 2024 22:53 GMT +00:00 - )

TCCO 3 Pack Non-Scratch Wire Dishcloth & Gaps Cleaning Brush, Multipurpose Wire Dishwashing Rags for Wet and Dry, Easy Rinsing, Reusable, Wire Cleaning Cloth for Kitchen, Sinks, Pots, Pans

(666)

₹297.00 (as of April 13, 2024 22:53 GMT +00:00 - )

RUSHMET Plastic Wall Shelves Kitchen Bathroom Shelf Self-Adhesive Sticker Hook Multipurpose Wall Holder Bathroom Storage Rack Box Strong Shower Rack Shelf (Set Of 4 Bath Self)

(145)

₹299.00 (as of April 13, 2024 22:53 GMT +00:00 - )

Tick Flea Chewable Tablet for Dogs Protect 3 Months (20 KG - 40 KG)

(12)

₹1,950.00 (as of April 13, 2024 22:53 GMT +00:00 - )