BIOLOGICS

 against pathogenic micro-organism. 

Biologics can be classified into two general categories

 1. Antigens

 2. Antibodies

ANTIGEN: An antigen is the material that provokes the immune response and it can be defined under three categories. 

Biologically

 Chemically

 Physically

a. Biologically definition of Antigens:

An antigen is the substance that when introduced into the tissue of man or other vertebrates,causes the formation of antibodies.

These antibodies then react specifically with the antigen that stimulated their production. 

 Properties of an antigen:

Immunogenicity

 Specificity

 ANTIGENIC DETERMINATES(EPITOPES)

  Small cemical sites on the antigen molecules called the antigenic determinates,the antibody combines with one or more these sites.

b. Chemically definition of antigen:  

Chemically antigens are Proteins, However some higher molecular weight polysaccharides are also antigenic.

c. Physically definition of antigen:

Antigen must possess a higher molecular weight .Weight more than 10,000 is required. The higher molecular weight is associated with the biologic property of immunogenicity(The capacity to induce antibody formation)

ANTIGENS DIRECTLY CONCERNED WITH INFECTIOUS DISEASES

 Exotoxins

 Proteins

 Capsule of bacteria

 Protein coats of virus particals

HAPTENS

“Compounds with a molecular weight lower than 10,000 can be partial antigens and are called Haptens”.

  Because of low molecular weight they cannot induce the formation of antibodies by themselves and lack the property of immunogenicity. However they can attached with the host proteins to form a complete antigen which will induce the formation of antibodies specific for the particular Hapten. 

Examples:

 Drug or their breakdown products may act as Hepten and this action is the basis of many drug allergies e.g. Penicillin Allergy.

Penicillin allergy occurs when immune system mistakenly reacts to a drug as a harmful substance.

ANTIBODY

An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein produced mainly by plasma cells that is used by the immune system to identify and neutralize pathogens such as bacteria and viruses. 

There are two types of antibodies

1. Circulating antibodies

2. Fixed antibodies

STRUCTURE OF ANTIBODY

Antibodies are immune system-related proteins called immunoglobulins. Each antibody consists of four polypeptides– two heavy chains and two light chains joined to form a "Y" shaped molecule. 

The amino acid sequence in the tips of the "Y" varies greatly among different antibodies. This variable region, composed of 110-130 amino acids, give the antibody its specificity for binding antigen

The amino acid sequence in the tips of the "Y" varies greatly among different antibodies. This variable region, composed of 110-130 amino acids, give the antibody its specificity for binding antigen. The variable region includes the ends of the light and heavy chains. Treating the antibody with a protease can cleave this region, producing Fab or fragment antigen binding that include the variable ends of an antib

The constant region determines the mechanism used to destroy antigen. Antibodies are divided into five major classes, IgM, IgG, Iga, IgD, and IgE, based on their constant region structure and immune function.

STRUCTURE OF ANTIBODY

TYPES OF ANTIBODIES

On the basis of physical, chemical  and immunological properties, the immunoglobulins can be divided into five subtypes.

IgG (70-75%) 

IgM (10%)

 IgA (10-15%)

IgD (1% or less)

IgE(0.001% or less)

1. IgG

IgG is the most abundant serum immunoglobulins(70-75%).

 It is the only antibody that can pass through the placenta.

Protects against bacterial or viral infection.

 Molecular wt. approx. 150,000

 Contains 1400 amino acids.

2.IgM 

When the new born infant begins its own antibody production ,the first immunoglobulin to appear is IgM. 

 Molecules of IgM are pentamers of the basic 4 chain immunoglobulin unit.

Found maily in blood and in lymph fluids 

3. IgA

These are found in relatively low concentration in blood serum.

 IgA is found in external secretions e.g, saliva, secretions of respiratory tract, GI tract, and form a specific defense mechanism in these areas of body.

4.IgD 

It is present on the surface of B-cells and plays a role in the induction of antibody production.

5. IgE

Associated with allergic reactions(when immune system overreact to environmental antigen and found in lungs, skin, and mucus membrane.

Types of Immunity

Immunity is classified into two major types.

Natural/Innate Immunity

 Acqiured Immunity 

Natural/Innate Immunity

The term natural or innate means the defense mechanism andowed at birth and that come into play immediately or within hours of an antigen appearance in the body.

 Acqiured Immunity 

On the other hand, acquired immunity is quiet specific and is in contrast to natural immunity.

 Generally it is subdivided in to 2 classes.

Active immunity

 Passive immunity

Each of which is further subdivided into “Acquired immunity”

Active Immunity

Naturally acquired active immunity

 Artificially acquired active immunity

Passive immunity

a) Naturally acquired Passive  immunity

b)  Artificially acquired Passive immunity

                           Active Immunity

Active immunity means the specific immunity developed by an individual in response to the introduction of antigenic substance into the body.

a)Naturally acquired active immunity

In this type of immunity, the antigenic substances may be received by the body in a natural manner.

b)Artificially acquired active immunity

Whereas in this type, antigenic substances may be received by the body through the administration of vaccines or toxoid.

                 Passive Immunity 

Passive immunity is the type developed by the introduction of preformed antibodies into the body.

 In this type, the body cells are not stimulated to produce their own antibodies .The immunity acquired by the individuals is not self developed ,but is passed from one individual to another, the term passive immunity is applied.

Naturally acquired Passive immunity

Occurs during pregnancy, in which certain antibodies are passed from the maternal into the fetal bloodstream. 

b) Artificially acquired passive immunity 

Short-term immunization by the injection of antibodies, such as gamma globulin, that are not produced by the recipient's cells.It is produced quickly but is not long lasting.

VACCINES

A vaccine is a biological 

preparation that provides 

active acquired immunity 

to a particular disease. A

 vaccine typically contains 

an agent that resembles a

 disease-causing micro-organism and is often made from weakened or killed forms of the microbe, its toxins or one of its surface proteins

Active immunization from vaccination 

Primary active immunization from vaccination develops more slowly than the incubation period of most infections and must be induced prior to exposure to infectious agent.

 Therefore general action of vaccines should be considered prophylactic.

  Active immunization with Non-living Vaccines

 Non living vaccines provides protection for only a limited time, so repeated vaccination is required to maintain protection against Typoid fever, cholera and plague. 

Active immunization with living Vaccines

Whereas active immunization  with living agents is generally preferable to immunization with killed vaccines because of a superior and more long lived immune response.

 For example: A single vaccination of measles, rubella  or mumps, is sufficient to produce a long lasting effects.

Use of vaccines is contraindicated under conditions in which the immune response is depressed e.g.,

 Therapy involving steroids

 Antineoplastic agents

 Immunosuppressive agents

Active immunization may cause fever, malaise, soreness at injection sites or allergic reactions. 

      

                    VIRAL VACCINES

 For prophylaxis against mumps, rubella, rubeola , smallpox, and yellow fever contains living viruses. 

 Inactivated or killed viruses are used in influenza and rabies vaccines. 

Preparations containing live attenuated or killed viruses are available for immunization against poliomyelitis

1. SMALLPOX VACCINE (چیچَک)

The smallpox vaccine helps the body to develop immunity to smallpox. The vaccine is made from a virus called vaccinia which is a “pox”-type virus related to smallpox. The smallpox vaccine contains the “live” vaccinia virus—not dead virus like many other vaccines. 

 Available in dried and liquid form, the later consist of a smooth ,aquoeus suspension of infected tissue that contain 40-60% sorbitol/glycerin.

DISCOVERY OF SMALLPOX VACCINE

The pioneering work of Dr.Edward Jenner in England in 1796 established that when a mild case of cowpox (vaccinia) is developed by a person, the same person is immune to smallpox.

Using this information , he inoculated a young boy with pus from a milkmaid infected with cowpox . Two months later, the boy was inoculated with pus from a patient infected with smallpox, but no disease developed. Immunity had been established.

METHOD OF PREPARATIION

Smallpox vaccine is the living virus of vaccinia (cowpox) that has been grown in the skin of a vaccinated bovine calf (Young domestic cow).

 The calf is prepared by washing and shaving its belly then scarifying the epidermis so that serum oozez through the cuts. 

 The seed virus is inoculated into scarifications merely by hand rubbing. 

 Calf is maintained in aseptic stall and given food and water during the growth of virus.

 The vesicles that develop are removed at the time of maximum potency.

 Thoroughly triturated and either made into a smooth suspension with an aqueous solution of glycerin or sorbitol or reduced to a dried pellet. 

USES & DOSE

Specific immunizing agent and is used as prophylactic before infection occur and creates active immunity that lasts for 7 years.

DOSE: Percutaneous and contents of 1 capillary tube by Multiple Puncture Method.

2.RABIES VACCINE 

Rabies vaccine is a sterile preparation of killed, fixed virus of rabies in dried form. The virus is obtained from duck embryos that have been infected with fixed rabies virus. Duck vaccine is sometimes called “Avianized vaccine”

USES & DOSE

An active immunizing agent and is recommended for the prevention of rabies in person bitten by an animal supposed or known to be rabid.

    

        S/C Injection o.d  for 14 days 

H.D.C.V

(HUMAN DIPLOID CELL CULTURE RABIES VACCINE):

A new vaccine prepared from virus grown in culture of Human diploid  cells, contains much less protein and with less chances of side effects

DOSE:

4-6 post-exposure doses shows that it is more effective than duck embryo vaccine.

3. YELLOw fever

Yellow fever is a serious disease caused by the yellow fever virus. It is spread through the bite of an infected mosquito and cannot be spread directly from person-to-person. 

YELLOW FEVER VACCINE

Yellow fever vaccine is an attenuated strains of yellow fever virus prepared by culturing the virus in the living embryo of the domestic fowl.

( Gallus domesticus).

Preparation:

The virus-infected ,chick embryo pulp is suspended in water  and, is suspended in water and after aseptic processing is distributed in suitable quantities into ampoules , and then ampoules are filled with dry nitrogen and flame sealed.

USES & DOSE

Active immunizing agent that is used to develop active immunity against disease. 

  S/C 0.5 ml

4. INFLUENZA VIRUS VACCINE

Flu is caused by influenza viruses, and is spread mainly by coughing, sneezing, and close contact. 

 Symptoms vary by age but can include,fever/chills , sore throat , muscle aches ,fatigue , cough, headache ,runny or stuffy nose.

Influenza virus vaccine is a sterile aqueous suspension of inactivated Influenza virus Type A& B , either individually or combined prepared from extra embryonic fluid of influenza virus infected chick embryo.

Preparation:

During commercial preparation of vaccine ,the virus growth are collected, concentrated and refined by ultracentrifugation and inactivated by UV radiations.

USES & DOSE

Active immunization against the disease

 I/M, S/C, 2 inj of 0.5 ml ,6-8 weeks apart

5. POLIOMYELITIS VACCINE

It is a viral disease that can effect nerves and can lead to partial or full paralysis.

 Poliomyelitis virus of type 1, 2, and 3 and viral strains are grown separately  in primary culture of Rhesus monkey kidney tissue.

USES & DOSE:

Create active immunity against disease

 I/M , S/C, 3 Inj of 1 ml , 4 weeks apart, 4th reinforcing dose of 1ml 6-12  months later.

Trivalent oral polio vaccine(TOPV)

Preparation of one or a combination of 3 types of live, attenuated virus. It has been manufactured in a manner suited for oral administration. Manufacturing is similar to poliovirus vaccine inactivated. 

USES & DOSE:

 Active immunizing agent

2 doses at interval of 8 weeks, 3rd dose after interval of 8 months. 

6. MEASLES VACCINES

Measles: It’s a disease mainly caused from a virus named “paramyxo virus”. This is a viral infection of the respiratory system – occurring mostly in childhood – cause fever and red rash.

Measles vaccines containing live  attenuated rubeola (measles) and rubella (German measles) viruses are available for active immunization against the disease. 

. 

Viruses for production of these vaccines are grown on cultures of either avian tissue or human diploid cell tissue 

i. Measles virus vaccine live or rubeola vaccine: 

Rubeola vaccine is prepared from attenuated viruses derived from the original Edmoston B strain and is claim to have high degree of antigenicity with low incidence of adverse effects. Rubeola virus is grown on cultures of chick embryo tissue.

Uses & Dose:

 Provides active immunization

Of children 15 months of age or older. 

Single 0.5ml s/c inj

ii) Rubella virus vaccine live/ German measle

It is prepared from the Wistar Institute RA 23/3 strain grown on human diploid cell tissue.

Uses & Dose:

Active immunization against 

German measle for children

aged 1 to puberty.

Single 0.5ml s/c inj

7. MUMPS VACCINE

Mumps is caused by a virus from the genus Rubula virus. Its symptoms include low-grade fever, respiratory problems, and most notably swelling of the salivary glands below the ear.  

Prepatration:

Mumps virus vaccine live is prepared with the B-level Jeryl Lynn strain of the virus , grown in cell cultures of chick embryo tissue.

Dose & Uses:

S/C Inj and provides active immunization for 10 years

COMBINATION VIRUS VACCINE

Combination live virus vaccines containing either measles virus and rubella virus, rubella virus and mumps virus or measle virus, rubella virus, mumps virus. (MMR)

Dose: S/C Inj of 0.5ml at 15 month age of child

RICKETTSIAL VACCINES

Rickettsia are cultured in chick embryo or in monkey kidney tissue cultures in a manner similar to that of virus.              

         TYPHUS FEVER 

Typhus is a disease caused by an infection with the Rickettsia bacteria. Fleas, mites, lice, or ticks transmit it when they bite you.

TYPHUS VACCINE: Typhus vaccine is a sterile suspension of the killed rickettsial organisms of a strains of typhus rickettsiae for antigenic activity.

USES & DOSE:

Active immunizing agent for typhus fever

 2 S/C Injections of 0.5 ml (4 weeks apart), followed by 0.5ml every 6-12 months.

BACTERIAL VACCINES

Bacterial vaccines consist of suspension of attenuated or killed pathogenic bacteria in isotonic sodium chloride  solution or other suitable diluents.

TYPHOID VACCINE 

Typhoid vaccine is a sterile suspension containing killed typhoid bacilli (Salmonella typhi) and consist of 1 billion typhoid organisms in each ml

Uses & Dose

2 Inj at a Dose of 0.5 ml ,S/C, 4 weeks apart, followed by 0.5ml every 3 years.

2)CHOLERA VACCINES: 

Sterile suspension of killed cholera vibrios (Vibrio cholerae)  is an isotonic sodium chloride 

solution or other suitable diluents. 

Uses & Dose:

S/C, I/M, 0.5 ml and then 1 ml 4 weeks later, 0.5ml dose repeated every six months.

3) PLAGUE VACCINE:

Plague vaccine is a sterile suspension , in an isotonic sodium chloride solution or other suitable diluent ,of killed Plague bacilli (Yersinia pestis)  and contains 2 billion  plague bacilli in each ml.

Uses & Dose

2, 0.5 ml I/M Inj, 4 weeks apart, then 0.2 ml 4-12 weeks later. 

4) PERTUSSIS VACCINES

Pertussis vaccine is a sterile bacterial suspension of killed pertussis bacilli (Bordetella pertussis ) 

Bordetella pertussis  is the organism that causes the disease known as whooping cough or pertussis. 

5. TUBERCULOSIS VACCINES

BCG vaccines are dried , living culture of the bacillus Calmette-Guerin strains of Mycobacterium tuberculosis isolated by two bacteriologist  Calmette and Guerin

 Uses& Dose:  I/D in doses of 0.1 ml

6. MENINIGOCOCCAL POLYSACCHARIDE VACCINE

It contains specific bacterial capsular polysaccharide for Neisseria meningitidis.

 Dose: 

Single S/C inj of 0.5 ml containing 50 μg meningococcal polysaccharide.

7. PNEUMOCOCCAL VACCINE,POLYVALENT

 Affords protection against 14 most prevalent capsular type of pneumococci accounts for 80% pneumococcal diseases and prepared by isolating and purifying polysaccharide antigen from strains of Streptococcus pneumoniae. 

Dose: Single 0.5 ml S/C , I/M

Toxins are bacterial waste products that are poisonous to animal body.

 EXOTOXINS:

When toxins are excreted from bacterial cells producing them and are dissolved in surrounding culture medium they are referred as Exotoxins.

ENDOTOXINS:

When toxins are retained within bacterial body , they are called endotoxins.

COMMERCIAL PREPARATION OF EXOTOXINS 

Highly virulent organisms are cultured in beef broth media and then killed by appropriate means. Organisms are removed by filtration through bacterial filter and filtrate contains toxins and other products is standardized on a suitable animal to determine minimum lethal dose.

FLUID TOXOIDS

Treating exotoxins with formaldehyde eliminates the toxic properties . The detoxified products are called as Fluid toxoids. 

ADSORBED TOXOIDS 

By adsorbing the fluid toxoid with aluminium phosphate, aluminum hydroxide  an adsorbed toxoid is produced, is when administered, result in slower release of antigen from site of injection  and subsequent production of higher or more prolonged antibody titers.

USES: 

Fluid and adsorbed toxoids produces active immunity against diphtheria and tetanus. 

DTP : Diptheria and tetanus toxoid combined with pertussis vaccine in combination known as DTP.

ANTITOXINS

Antitoxins are prepared from bloods of animals, usually horses, that have been immunized by repeated injections of specific bacterial exotoxins. The toxin in constantly increasing dose, induces the formation of antitoxins in the blood of infected animals.

THERAPEUTICALLY IMPORTANT ANTITOXINS

DIPHTHERIA ANTITOXINS

TETANUS ANTITOXINS

BOTULISM ANTITOXINS

1.DIPHTHERIA ANTITOXINS

Sterile, non –pyrogenic solution of the refined and concentrated proteins, chiefly  globulins containing antitoxic antibodies obtained from blood serum or plasma of healthy horses that have been immunized against diptheria toxin or toxoid.

POTENCY: NLT ( NOT LESS THAN) 500 antitoxin units per ml

USE & DOSE:

Passive immunizing agent and produce passive immunity against diptheria. 

I/M OR I/V 

Prophylactic dose: 1000-10,000 units

Therapeutic dose: 20,000-80,000 units

2. TETANUS ANTITOXINS

It is a steirle , non pyrogenic solution of the refined and concentrated proteins, chiefly globulins containing antitoxic antibodies obtained from blood serum or plasma of healthy horses immunized against tetanus toxin or toxoids. 

POTENCY: 

NLT 400 antitoxin units per ml

Use & Dose:

Passive immunity against tetanus

 I/M, S/C

Prophylactic dose: 3000-10,000 units

 Therapeutic dose: 40,000-100,000 units

3. BOTULISM ANTITOXINS

Sterile , non pyrogenic solution of refined and concentrated antitoxic antibodies, chiefly globulins, obtained from blood serum or plasma of healthy horse that have been immunized against toxins produced by both type A and type B and type E strains of clostridium botulinum

Use & Dose: Positive immunizing agent

I/V 20,000 units repeated at 2-4 hr internals as necessary. 

         

VENOMS & ANTI-VENOMS

VENOMS

Venoms are poisonous excretions secreted by animals (certain snakes and spiders), introduce into the bodies of their victims by biting or stinging etc. 

Poisonous snake bite often causes severe pain, amputation and death. 

SNAKE VENOMS/VENINS

Snake venoms are obtained by holding the poisonous snake over a conical container covered with a sheet of thin rubber . The snake strikes the rubber and penetrate with its fangs where the semisolid venom is ejected in to the container. 

Mixtures of venins from poisonous snakes of a locality, country or continent are prepared and used in the preparation of POLYVALENT ANTIVENINS(Anti snakebite serum). 

POLYVALENT ANTIVENINS: Sterile, non pyrogenic preparations derived by drying a frozen solution of specific venom –neutralizing globulins which are obtained from serum of healthy horses immunized against 4 species of venomous snakes.

Family: Crotalidae

Crotalus atrox  ( Western diamondback)

                                         4 Feet 

2. Crotalus adamenteus (Florida  diamondback)

                                                7.8 feet 

3.  Crotalus durissus (South American Rattlesnake 

                                                       4.9 feet

Bothrops atrox (Common lancehead)

                                                            6.6 feet

Uses and Dose

Passive immunizing agent

 I/M 10 ml recostitued antivenin

 I/V infusion 1:10 dilution of antivenin in Nacl Inj (5% Dextrose Inj)

SPIDER- BITE ANTIVENIN

Latrodectus mactans /Black widow spider 

Black widow spider anti-venom is prepared by serum obtained from horses immunized against venom of black widow spider .

 Use & Dose: I/M, I/V over a 15 min period , diluted with 10-50 ml saline solution. 

ANTISERUMS

Blood serum that contains specific antibodies against an infective organisms or poisonous substances and is used to pass on passive immunity to many diseases.  

ANTI-RABIES SERUM:

Sterile, non-pyrogenic solution containing antiviral substances obtained from blood serum of plasma of a healthy horse that have been immunized against rabies by means of vaccine. 

Use & Dose:

Injection provides immediate protection against rabies.

Single dose I/M 1000 units per 40 pounds body weight

R