(a) Cell-mediated immunity
When pathogens are destroyed by cells without producing antibodies, then it is known as cell mediated immune response or cell mediated immunity. This is brought about by T cells, macrophages, and natural killer cells.
(b) Antibody mediated immunity or humoral immunity
When pathogens are destroyed by the production of antibodies, then it is known as antibody mediated or humoral immunity. This is brought about by B cells with the aid of antigen presenting cells and T helper cells. Antibody production is the characteristic feature of vertebrates only.

Malaria vaccine is used to prevent malaria. The only approved vaccine as of 2015 is RTS, S(Mosquirix). It requires four injections and has relatively low efficacy (26-50%). Due to this low efficacy, WHO does not recommend the use of RTS, S vaccine in babies between 6 and 12 weeks of age 

The intake of certain drugs for a purpose other than their normal clinical use in an amount and frequency that impair one's physical, physiological and psychological functions is called drug abuse.

(i) Alcohol interferes with the ability of the liver to break down fat. Over time fat accumulation and high levels of alcohol destroy the liver cells and a scar tissue grows in the place of dead cells. This scarring of the liver is called "Liver cirrhosis ".
(ii) Alcohol irritates the stomach lining due to the production of excess acid leading to ulcers.
(iii) Excessive alcohol use weakens the heart muscle, causing scar tissue to build up in the cardiac muscle fibers. As a result, heavy drinkers have an increased risk of high blood pressure, stroke, coronary artery disease and heart attack.

According to the World Health Organization (WHO), hygiene refers to "conditions and practices that help to maintain health and prevent the spread of diseases."

(i) Commonly called filarial worm. It is found in the Iymph vessels and lymphnodes of man.
(ii) Wuchereria bancrofti is sexually dimorphic viviparous and digenic. The life cycle is completed in two hosts, man and the female Culex mosquito.
(iii) The accumulation of the worms block the lymphatic system resulting in inflammation of the lymph nodes.
In some cases, the obstruction of lymph vessels causes elephantiasis or filariasis of the both scrotum and mammary glands.

The common cold has evaded medical sciences advances for two primary reasons:
(i) The first issue is that the colds are most often caused by a rhinoviruses-a large family of viruses with hundreds of variants. This makes vaccination an impossibility and gives our immune system a challenging task.
(ii) Secondly, these viruses evolve rapidly so even if we could produce vaccines to cover the full spectrum of rhinoviruses, they would quickly become resistant.

(i) "Wuchereria bancrofti".
(ii) Chronic inflammation of the lymph nodes. Obstruction of lymph in the vessels of the lower limb.
(iii) Transmitted through an agent/vector called Female Culex mosquito.

(i) For Diphtheria:
Causal agent: Corynebacterium diphtheria.
Mode of Transmission: Droplet infection through breathing.
Symptoms: Fever, sore throat, hoarseness and difficulty in breathing
(ii) For Typhoid: 
Causal agent: Salmonella typhi
Mode of Transmission: Through contaminated food and water
Symptoms: Headache, abdominal discomfort, fever and diarrhea.

In the 1950s, experiments conducted by Porter and Edelman revealed the basic structure of the immunoglobulin.
An antibody molecule is Y shaped structure that comprises of four polypeptide chains, two identical light chains (L) of molecular weight 25,000 Da (approximately 214 amino acids) and two identical heavy chains (H) of molecular weight 50,000 Da (approximately 450 amino acids). The polypeptide chains are linked together by di-sulphide (S-S) bonds. One light chain is attached to each heavy chain and two heavy chains are attached to each other to form a Y shaped structure. Hence, an antibody is represented by H₂L₂.
The heavy chains have a flexible hinge region at their approximate middles.
Each chain (L and H) has two terminals. They are C - terminal (Carboxyl) (or) -COOH and amino or N-terminal (or NH₂). Each chain (L and H) has two regions and they have variable (V) region at one end and a much larger constant (C) region at the other end.
Antibodies responding to different antigens have very different (V) regions but their (C) regions are the same in all antibodies.
In each arm of the monomer antibody, the (V) : regions of the heavy and light chains combine to form an antigen - binding site shaped to 'fit' a specific antigenic determinant.
Consequently each antibody monomer has two such antigen - binding regions.
The (C) regions that forms the stem of the antibody class and serve common functions in all antibodies.
The functions of immunoglobulin are agglutination, precipitation, opsonisation neutralization etc.

Life cycle of Plasmodium :
(i) The life cycle of Plasmodium involves three phases namely schizogony,gamogony and sporogony.
(ii) The parasite enters the human blood stream through the bite of an infected female Anopheles mosquito.
(iii) As it feeds, the mosquito injects the saliva containing the sporozoties.
(iv) The sporozoite within the blood stream enter the hepatic cells of the liver.
(v) It undergoes multiple asexual fission (schizogony) and produces merozoties which are released from liver cells.
(vi) The merozoites penetrate the RBC's. Inside the RBC of blood, the merozoite begins to develop unicellular trophozoites. The trophozoite grows in size and a central vacuole develops p them to one side of cytoplasm and becomes the signet ring stage.
(vii) The trophozoite nucleus divides asexually to produce the schizont.

(viii) The schizont divides and produces mononucleated merozoites.
(ix) Eventually the erythrocyte lyses, releasing the merozoites and haemozoin toxin into the blood stream to infect other erythrocytes.
(x) Lysis of red blood cells results in fever and other symptoms.
(xi) This erythrocytic stage is cyclic and repeats itself approximately every 48 to 72 hours or longer depending on the species of Plasmodium involved.
(xii) The sudden release of merozoites triggers an attack on the RBCs.
(xiii) Occasionally, merozoites differentiate into macrogametocytes and microgametocytes. when these are ingested by a mosquito, they develop into male and female gametes respectively.

The human immunodeficiency virus belongs to the genus Lentivirus. When observed under the electron microscope, HIV is seen as a spherical virus, 100-120 nm in diameter, containing a dense core surrounded by a lipoprotein envelope. The envelope has .glycoprotein (GP) spikes termed GP 41 and GP 120. At the core, there are two large single-stranded RNA. Attached to the RNA are molecules of reverse transcripte. It also contains enzymes like protease and ribonuclease. The core is covered by a capsid made of proteins. This is followed by another layer of matrix proteins as shown above.

S.No	Primary Immune Response	Secondary Immune Response
1.	It occurs as a result of primary contact with an antigen.	It occurs as a result of second and subsequent contacts with the same antigen
2.	Antibody level reaches peak in 7 to 10 days	Antibody level reaches peak in 3 to 5 days.
3.	Prolonged period is required to establish immunity	It establishes immunity in a short time.
4.	There is rapid decline in antibody level	Antibody level remains high for longer period.
5.	It appears mainly in the lymph nodes and spleen.	It appears mainly in the bone marrow followed by the spleen and lymph nodes

S.No	Diseases	Caustive agent	Site of infection	Mode of transmission	Symptoms
1.	Common cold	Rhino viruses	Respiratory tract	Droplet infection	Nasal congestion and discharge sore throat, cough and headache
2.	Mumps	Mumps cirus (RNA virus)Paramyxa cirus	Salivary glands	Saliva and droplet infection	Enlargement of the parotid glands
3.	Measles	Rubella virus (RNA virus Parmyxco),	Skin and respiratory tract	Droplet infection	Sore throat, running nose cough and fever. reddish rashes  on the skin, neck and ears
4.	Viral hepatitis	Hepatitis - B virus	Liver	Parenteral route blood transfusion	Liver damage, jaundice, nausea yellowish eyes, fever and pain in the abdomen
5.	Chicken pox	Varicella-Zoster virus (DNA Virus	Respiratory tract,skin and nervous	Droplet infection and direct contact	Mild fever with itchy skin, rash and blisters

(i) A vaccine is a biological preparation that provides active acquired immunity to a particular disease and resembles a disease-causing microorganism and is often made from weakened or attenuated or killed forms of the microbes, their toxins, or one of its surface proteins.
(ii) Vaccines "teach" our body how to defend itself when viruses or bacteria, invade it.
(iii) Vaccine initiates the immunization process. The vaccines are classified as first, second and third generation vaccines.
First generation vaccine:
(i) First generation vaccine is further subdivided into live attenuated vaccine, killed vaccine and toxoids.
(ii) Live attenuated live vaccines use the weakened (attenuated), aged, less virulent form of the virus
(iii) Eg. Measles, Mumps and Rubella (MMR) vaccine and the Varicella (chickenpox) vaccine, killed (inactivated) vaccines are killed or inactivated by heat and other methods. Eg. Salk's polio vaccine.
(iv) Toxoid vaccines contain a toxin or chemical secreted by the bacteria or virus.
(v) They make us immune to the harmful effects of the infection, instead of to the infection itself.
(vi) Eg. DPT vaccine (Diphtheria, pertussis and Tetanus), (Triple antigen).
Second generation vaccine: contains the pure surface antigen of the Pathogen. :
Eg. Hepatitis-B vaccine 
Third generation vaccine: contains the purest and the highest potency vaccines which are synthetic in generation. The latest revolution in vaccine is DNA vaccine (or) recombinant vaccine

(a) MALT - Mucosal - Associated Lymphoid Tissue
(b) NACO - National AIDS Control Organisation

	Cell Mediated Immunity (CMI)	Antibody Mediated Immunity (AMI)
a.	In CMI, pathogens are destroyed by cells without producing antibodies.	In AMI, pathogens are destroyed by antibodies.
b.	It is carried out by T cells, Macrophages NK cells	It is carried out by B cells, T helper cells, APC cells

Tissue damage and infection induce leakage of vascular fluid, containing chemotactic signals like serotonin, histamine, and prostaglandins. They influx the phagocytic cells into the affected area. This phenomenon is called diapedesis,

Causative organisms of filariasis is Wuchereria bancrofti (filarial worm). The site of infection is lymph vessels and lymph nodes

The other host of filarial worm is female Culex mosquito
The other host of Plasmodium is female Anopheles mosquito

Fungal disease: Candidiasis, Athlete's foot
Helminthic disease: Ascariasis, Filariasis

Infectious disease	Non-infectious disease
Disease which are transmitted form one person to another are called infectious disease. e.g. Common cold	Disease which do not transmitted form one person to another are called non-infectious disease. e.g. Anaemia

It is a toxin produced by lysis of insected red blood cells in a person affected with malaria. This causes malaria symptoms such as fever, chills, shivering etc.,

In the life cycle of plasmodium, the oocyte undergoes meiosis by a process called sporogony to from sporozoites. This takes place in the gut of the mosquito

Causal agent of swine flu HI N1 virus strain Symptoms sore throat, fever, cough, body ache and weakness.

Autoimmunity is due to an abnormal immune response in which the immune system fails to properly distinguish between self and non-self and attacks its own body. Our body produces antibodies (autoantibodies) and cytotoxic T cells that destroy our own tissues. If disease-state results, it is referred to as auto-immune disease.
Thus, autoimmunity is a misdirected immune response. Eg., Rheumatoid arthritis and multiple sclerosis

(i) A simple blood test is available that can determine whether the person has been infected with HIV.
(ii) The ELISA test (Enzyme Linked Immuno Sorbent Assay) detects the presence of HIV antibodies.
(iii) It is a preliminary test. Western blot test is more reliable and a confirmatory test.
(iv) It detects the viral core proteins. If both tests detect the presence of the antibodies, the person is considered to be HIV positive.