Vaccination & Immunisation | Biology Class 12 - NEET PDF Download

Vaccine

Vaccine is suspension of inactivated pathogens or antigenic protein of pathogen which is taken orally or injected to provide immunity for that pathogen.

Vaccine

History of Vaccination

(i) Edward Jenner (1796) noticed that milkmaid did not suffer from small pox but they had scabs of cow pox. He transport the material from sore of milkmaid who was suffering from cow pox to the young body of 8 year old.

After sometime he injected live small pox material into that boy. But symptoms of disease did not appear. He tried this procedure on other person and got success. He gave the term vaccination for this process.

(ii) Louis Pasteur:  He discovered the process of inactivating the pathogen & prepared vaccines for Anthrax, chicken cholera, Rabies.

(iii) Von Behring : - He discovered the process of passive immunization and prepared the antidiptherial serum by injecting diptheria antigen into sheep.

Von Behring is known as 'Father of Passive Immunization'.

Principle of Vaccination

It is based on memory of immune system. When a antigenic material is injected in a healthy person, it generates antibodies and memory cell as a primary immune response. When this activated pathogen enters for the second time inside the body of vaccinated person, memory cells rapidly recognize and respond with massive production of lymphocytes and antibodies. So it destroys pathogen rapidly and disease does not appear. Person becomes resistant for that disease after vaccination.

Types of Vaccines

1. First Generation Vaccines

These vaccines are prepared by inactivating the whole pathogen but they have side effects.

(i) Live attenuated (OPV, BCG, Small pox, Influenza etc.)

(ii) Killed (Typhoid, Salk polio, Cholera, Rabies, Plague etc.)

(iii) Toxoid (Diphtheria, Tetanus)

(iv) Combination (DPT, MMR) 

2. Second Generation Vaccines 

Antigenic polypeptides of pathogens are produced with recombinant DNA technology in transgenic organisms.

These are made by multiplication of surface antigen by genetic engineering. They have no side effects. e.g. Hepatitis B vaccine produced from transgenic yeast, Meningococcal, Pneumococcal etc.

3. Third Generation Vaccine

These are highly potent, synthetic in nature & prepared by genes they are also called DNA vaccine.  eg. Leukaemia virus vaccine.

HLA System : Human leucocyte antigens (HLA) were first discovered on leucocytes. Out of the various genes for histo compatibility antigens, most of the transplantation antigens are located on a portion of chromosome-6. This is called MHC or Major Histo Compatibility complex or HLA complex. The recipients immune system can recognize the histocompatibility antigens on the donar organ and accordingly acceptor reject it.

The array of HLA alleles on a homologue of our chromosome 6 is known as a haplotype. An individual inherits one HLA haplotype from each parent.

Only identical twins can have identical haplotype.

The best HLA matching can be observed within the same family.

Tissue Typing: The procedure carried out to match HLA proteins of donar and recepient.

Preference Order of Transplants: Identical twins > Sibling > Parent > unrelated donor.

Tissue Grafting: This is based on HLA (Human Leucocyte antigen) or MHC (Major Histocompatibilty Complex). It is present on the surface of Leucocyte. Tissue typing is done before tissue grafting.

Gene of this antigen is present on sixth chromosomes. Cyclosporin drug is used as a immunosup present drug during tissue grafting.

Type of Tissue Grafting:

(i) Autograft : (most successful) Transplantation of tissue from one body part into another body part of an individual.

(ii) Isograft : Transplantation of tissue in between the individual of same genetic constitution Ex. - Graft between identical twins

(iii) Homo or Allograft : Tissue grafting in between the genetically dissimilar individual of the same species. e.g. Family members or intra species graft.

(iv) Hetero or Xenograft : Tissue grafting in between organism of different species.

Successful Graft Order :- Self> identical twins> Siblings > Parents > Unrelated donar

Immune System Disorder

Improper functioning of immune system may cause discomfort (Allergy), disease (AIDS) or even death (anaphylactic shock). Improper functioning divided into 3 classes.

(1) Hyper sensitive disorder or Allergy : When a person show hyper response or hyper sensitiveness for a common antigen or agent then it is called allergy.
The agents which cause allergy are called allergen. Common allergens can be pollen grains, food (egg, fish), medicines (penicilline), cold, heat, sunlight, fibres etc.
Physiology of Allergy :-More Secretion of histamine from mast cell & more production IgE antibodies in response to a common antigen or allergen.
Manifestations : (effect) →

(i) Bronchial Asthma : It is common manifestation of allergy. It is allergy of lungs when an allergen enters inside the body by inhalation. It comes in contact with respiratory tube. This is characterised by the spasm of the smooth muscles present in the walls of the bronchiole. It is generally caused due to the hypersensitivity of the bronchiole to the foreign substances present in the air passing through it. The mucous membranes on the wall of the air passage start secreting excess amount of mucous, which may close the bronchi, as well as bronchiole.
Symptoms : coughing and difficulty in breathing mainly during expiration.(Wheezing)

Prevention and Cure 

•  Avoiding exposure to the foreign substance or allergens is the best preventive measure.

•  Hyposensitisation (by exposing small doses of the specific allergen) is the other preventive measure

•  Antibiotic therapy for removing the infection, and use of bronchodilator drugs, as well as inhalers for symptomatic relief.

(ii) Hay Fever : Mucosa of eyes and upper respiratory passage become hyper secretory in response to allergen (pollen grain).

(iii) Urticaria - Multiple, Circumscribed raised pinkish itchy blisters of skin

(iv) Eczema (Dermatitis) - Reddening of skin, Vesicle formation then rupture, scales formation.

(v) Anaphylactic shock : This is generalized and severe form of allergy. When a allergen (penicillin) enter into blood, it stimulates the secretion of histamine from the mast cell of whole body, this causes the vasodilation and increase permeability of blood vessel. So large amount of fluid is leaked out form blood vessel into extra cellular space and decrease in blood volume cause fall in blood pressure that may leads to death.

(2) Auto Immune Disorder : When the immune system does not discriminates between self and non-self antigen, antibodies are formed against the self antigen these antibodies destroy the self antigen and also the self tissue of the body.
So, the antibody formation against self antigen is called. Auto immunity Example –

1.  Myasthenia Gravis : In this disorder, antibodies are formed against acetylcholine receptors so these receptors are destroyed. It causes depressed nerve conduction at myoneuronal junction and B movements of muscles. Muscle become degenerate after some time.

2.  Pernicious (Destructive) Anemia : In this disorder, antibodies are formed against castle intrinsic factor (Stomach) so the vitamin B₁₂ is not absorbed in intestine and blood formation is decreased. This deficiency of blood is called pernicious anemia.

3.  Hashimoto Disease : Antibodies are formed against the thyroid gland. These antibodies destroy the thyroid gland and deficiency of thyroid hormone is called Hypothyroidism.

4.  Rheumatoid Arthritis : It is due to presence of rheumatoid factor (a type of immunoglobulin IgM). It is the primary symptom of inflammation of synovial membrane. If it is left untreated, then the membrane thickens and synovial fluid increases, exerting pressure that causes pain. The membrane then starts secreting abnormal granules, called pannus, which after accumulating on the surface of the cartilage, cause its erosion. As a result, the fibrous tissues are attached with the bones and become ossified, making the joints immovable. Treatment : pain and inflammation by heat treatment and physiotherapy.Joint replacement surgery is done in extreme cases.

5. I.D.D.M : Insulin dependent diabetes mellitus. Antibodies are formed against the B cell of pancreas that cause the deficiency of insulin in body and this called I.D.D.M..Symptoms are hyperglycaemia, glycosuria, polyuria, polydipsia (excessive thirst), polyphagia (increase food intake)

6.  Multiple sclerosis : Antibodies are formed against the myline sheath of nerve cells. Destruction of myline sheath causes neurological dysfunction.

(3) Immuno Deficiency Disorder : May be due to gene mutation, gene deficiency, infection, nutritional deficiency & accidents.

1. De-George's syndrome or Thymic aplasia- In this syndrome deficiency of T-cells occurs due to inactive thymus gland.

2. Bruton's agammaglobulinemia- Deficiency of gamma antibodies occurs due to deficient fomation of Bcells.

3. S.C.I.D. : Severe combined immuno deficiency :  This disorder is due to gene mutation or gene deficiency of enzyme adenosin deaminase. This enzyme involved in formation of T and B lymphocytes. SCID is characterized by very low number of circulating thymocytes affected individual die at an early age. Treatment – Gene therapy

4. A.I.D.S. (Acquired immuno deficiency syndrome) : HIV attaches on T-helper cells. This cause the decrease count of T-helper cell from normal 950/mm³ to less than 200/mm³.

Immuno-Therapy 

Immuno therapy is a treatment procedure that involves suppression or augmentation of immune responses, to achieve therapeutic effects. Manipulation of the immune response can be carried out by modulating various components involved in it. Cytokines are natural immuno modulators secreted by one type of immune cell that elicits response in another type of immune cell. these include interleukins, interferons and tumour necrosis factors.
Immuno modulators are, principally, drugs that modulate the activity of a patient's immune response, either up or down, until a desired level of therapeutic effect is reached. There are two general clinical approaches of immuno-modulation.

1.  Immuno-potentiation therapies : This includes administration of immuno-potentiating agents like preformed antibodies, or immuno-potentiating drugs. This strategy augments the immune response.

2.  Immuno-suppressive therapies : When the patient's immune system becomes activated against his or her own body, in situations such as, autoimmune diseases, the response is suppressed by using specific therapies.

These include inhibitors of cell division, cytokine production, etc.

(1) Phenylketonuria :- Due to deficiency of phenyl alanine hydroxylase, phenylalanine increase in blood & this phenylalanine or phenyl pyruvic acid accumulates in brain & destroy the brain cells. This causes mental retardation. These individuals are called phenyl pyruvicidiots.

(2) Alkaptonuria (Black urine disease) – This disorder is due to deficiency of enzyme homogentisic acid oxidase. So, homogentisic acid does not metabolises into tyrosine. Deposited in amino acid and a concentration of alkaptone or homogentisic acid in blood and tissue like joints, ligament, tendon, cartilage and also excrete in urine so it is called alkaptonuria.
When this urine comes in contact with air, it turns black due to oxidation of homogentisic acid so it is also called black urine disease.

(3) Albinism : This disorder is due to deficiency of enzyme tyrosinase. Therefore the body parts like skin, iris of eye etc., becomes melanin deficient. Melanin provide protection against U.V. rays.

(4) Tay-sach's disease or Infantile amourotic idiocy : This disease was first reported by tay and sac. This genetic disorder is due to deficiency of enzyme β –N acetyl hexose aminidase and is involved in fat metabolism. So, the fat(conjugate lipid) accumulates in brain(ganglioside cell) and spinal cord and damages these cells. This causes mental retardation and paralysis of a normal born child and this child does not survive more than 3-4 years. There is no treatment of Tay-sach's disease.

(5) Thalassemia (Thalassa - sea) (Mediterranean anemia or cooley's anemia) This disorder was, first found in population of mediterranean region. Frame shift mutation causes the deficiency of β and α genes present on 11^th & 16^th chromosomes respectively. So decrease synthesis of β and α polypetide chain of hemoglobin, (Mainly b–chain is affected) abnormal type or decreased hemoglobin is formed in R.B.C. This deform the R.B.C. and R.B.C. become hemolytic in nature.
So hemolytic anemia appear in this disorder.
Treatment : Blood transfusion or bone marrow transplantation.

(6) Sickle cell anemia (11^th chromosome): Glutamic acid is replaced by valine at the 6^th position of β chain of hemoglobin. This abnormal Hb change the shape of RBC from spherical to sickle shape and these RBC's become hemolytic in nature and produce haemolytic anemia. Sickle cell anemic patients are resistant against malaria (Falciparum malaria)

Old NCERT Syllabus

X-Linked recessive disorders :

(7) G-6-Phosphate dehydrogenase deficiency syndrome – G-6-PD enzyme present in RBC. This enzyme stabilizes the membrane of R.B.C. Deficiency of this enzyme causes rupture of R.B.C. when it comes in contact with sulfa drug, chloroquine, Fava (Favism) bean legumes.

(8) Duchenne's muscular dystrophy – Dystrophin protein is absent in muscles, this protein helps in conduction of Ca⁺⁺ ion. Due to deficiency of dystrophin protein, muscles contraction does not occur properly.
Autosomal dominant gene mutational disorder

(1) Polydactyly : Presence of extra fingers and toes

(2) Brachydactyly : Presence of abnormal short fingers & toes.

(3) Huntington chorea :- In this disorder dominant mutation occur on 4^th chromosomes so the mental and muscle degeneration occurs in the patients. This causes abnormal movement of limbs and defective speech.
This disease appears at the age of 25–55 yrs. (late on set) Nerve degeneration causing involuntary shaking of legs, arms and head.

(4) Achondroplasia : Defective formation of cartilagenous bones causing dwarfism

(5) Marfan syndrome – 15^th chromosome – Long & thin body, Myopia, long Arachnodactyly fingers, Mitral valve prolapes. Connective tissue disorder effect the skeleton, eye and cardiovascular system.