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IMMUNOLOGICAL TECHNIQUES 

1. State the functions of blood plasma

Plasma is the clear liquid portion of the blood.  90% of plasma is water.  The other 10% contains many types of molecules, including nutrients, glucose, vitamins, cellular wastes, salts, and proteins.   Plasma serves as a fluid portion in which, salts , sugars ,nutrients , hormones ,enzymes , antibodies  etc dissolve in as they get transported from one part of the body to another.

There are three major types  of proteins which exist in plasma.  These are albumin, fibrinogen, and globulins.  Each proteins has a specific function to perform.  The albumin keeps water from leaving the blood and entering the surrounding cells by osmosis.  It does this by helping to keep the concentration of the water within the blood the same as the concentration in the body tissues.  The fibrinogen aids in the clotting of the blood.  Some globulins transport proteins and other substances from one part of the body to the next.  Other globulins are known as antibodies, which help to fight of infection.  Antibodies are proteins that attach to and help destroy foreign substances in the body

2. State the functions of different types of white blood cells

White blood cells  defend the body  against diseases.  They are capable of amoeboid movement , these enables them  to squeeze themselves  through the tiny pores  in the capillary wall  so as to reach  the tissue and the site of infection

NB white blood cells are the  major  immunologically active cells  of the immune system ( others are  plasma cells , platelets  and mast cells)

There are five different types of White blood cells and are classified mainly based on the presence and absence of granules.

1. Granulocytes
2. Agranulocytes

a.Granulocytes

They are leukocytes, with the presence of granules in their cytoplasm. The granulated cells include- eosinophil, basophil, and neutrophil.

1. Eosinophils

They are the cells of leukocytes, which are present in the immune system.

These cells are responsible for combating infections in parasites of vertebrates and for controlling mechanisms associated with allergy and asthma.

Eosinophil cells are small granulocyte, which are produced in the bone marrow and makes 2 to 3 per cent of whole WBCs. These cells are present in high concentrations in the digestive tract.

1. Basophils

They are the least common of the granulocytes, ranging from 0.5 to 1 per cent of WBCs.

They contain large cytoplasmic granules, which plays a vital role in mounting a non-specific immune response to pathogens, allergic reactions by releasing histamine and dilates the blood vessels.

These white blood cells have the ability to be stained when exposed to basic dyes, hence referred to as basophil.

These cells are best known for their role in asthma and their result in inflammation and bronchoconstriction in the airways.

They secrete serotonin, histamine and heparin.

• Neutrophils

They are normally found in the bloodstream.

They are predominant cells, which are present in pus.

Around 60 to 65 per cent of WBCs are neutrophils with a diameter of 10 to 12 micrometres.

The nucleus is 2 to 5 lobed and cytoplasm has very fine granules.

Neutrophil helps in the destruction of bacteria with lysosomes, and it acts as a strong oxidant.

Neutrophils are stained only using neutral dyes. Hence, they are called so.

Neutrophils are also the first cells of the immune system to respond to an invader such as a bacteria or a virus.

The lifespan of these WBCs extend for up to eight hours and are produced every day in the bone marrow.

1. Agranulocytes

They are leukocytes, with the absence of granules in their cytoplasm. Agranulocytes are further classified into monocytes and lymphocytes.

1. Monocytes

These cells usually have a large bilobed nucleus, with a diameter of 12 to 20 micrometres.

The nucleus is generally of half-moon shaped or kidney-shaped and it occupies 6 to 8 per cent of WBCs.

They are the garbage trucks of the immune system.

The most important functions of monocytes are to migrate into tissues and clean up dead cells, protect against the bloodborne pathogens and they move very quickly to the sites of infections in the tissues.

These white blood cells have a single bean-shaped nucleus, hence referred to as Monocytes.

1. Lymphocytes

They play a vital role in producing antibodies.

Their size ranges from 8 to 10 micrometres.

They are commonly known as natural killer cells.

They play an important role in body defence.

These white blood cells are colourless cells formed in lymphoid tissue, hence referred to as lymphocytes.

There are two main types of lymphocytes – B lymphocytes and T lymphocytes.

These cells are very important in the immune systems and are responsible for humoral and cell-mediated immunity.

3. What are immunity and different types of immunity?

 Immunity is defined as the ability of the body to protect against all types of infectious diseases by defending against disease-causing pathogens like bacteria, virus, fungi and other toxic substances from invading our body. There are two types of immunity:

1. Innate Immunity or Natural
2. Acquired Immunity
3. . Define Antigens and Antibodies.
4. Antigens–They are the large molecules of proteins and polysaccharides present on the surface of cells. These molecules function by triggering the production of antibodies by inducing an immune response.
5. Antibodies— The are proteins produced by the immune system, which functions by defending the host against foreign invasion.
6. Outline three general steps through which antigen- antibody  reaction occur
7. Name  any two types of antigen-antibody reactions
8. What is the role of lymph nodes in our immunity response?

Lymphocytes present in the lymph nodes prevent microbes or antigens from entering through the tissue and lymph fluid by filtering out, disposing and immobilizing pathogens.

 

 

 

8. How would a person’s immune system be affected in the absence of the thymus gland?

T-Lymphocytes in our body mature in the thymus gland. If the thymus gland is removed from the body, T-Lymphocytes will fail to mature causing the immune system to not develop. Thus the person turns susceptible to most of the diseases.

9. Define the term immunoglobulins

Immunoglobulins are specialized proteins called antibodies  that are responsible for  immune system-related.Organisms specifically animals respond to infection or foreign materials  by producing in their serum substances  that have properties for reacting with the foreign bodies . These substances are called antibodies and their production is stimulated by antigens . antigens are  either proteins , polysaccharides ,glycolipids  or  glycoproteins  in nature .

 

10. Name  and state functions of any four types of immunoglobulins  

There are five main types of immunoglobulins, also known as antibodies, which play crucial roles in the immune system. Here are four types of immunoglobulins along with their functions:

 

1. IgG (Immunoglobulin G):

 

Function: IgG is the most abundant type of antibody in the bloodstream and plays a significant role in long-term immune responses. It provides protection against bacterial and viral infections by binding to pathogens and marking them for destruction by other immune cells. IgG also plays a role in providing passive immunity to newborns through placental transfer from the mother.

1. IgM (Immunoglobulin M):

 

Function: IgM is the first antibody produced during an initial immune response. It acts as a primary defense against pathogens and activates complement proteins, which help in the destruction of foreign invaders. IgM is typically present in higher levels during early stages of infection or as a response to vaccination.

1. IgA (Immunoglobulin A):

 

Function: IgA is primarily found in body secretions such as saliva, tears, mucus, and breast milk. It provides localized immunity and plays a vital role in defending the mucosal surfaces of the respiratory, gastrointestinal, and genitourinary tracts. IgA prevents pathogens from attaching to mucosal membranes and helps neutralize toxins and viruses.

1. IgE (Immunoglobulin E):

 

Function: IgE is involved in allergic responses and defense against parasites. It triggers the release of histamine and other chemicals from mast cells and basophils, leading to allergic reactions such as inflammation and bronchoconstriction. IgE also plays a role in protecting against certain parasitic infections by initiating an immune response against them.

 

1. IgD (Immunoglobulin D):

 

Function: IgD is found in low levels in the bloodstream and on the surface of B cells. Its exact function is not fully understood, but it is believed to play a role in the activation and differentiation of B cells during the immune response.

 

11. State the significance of mother’s milk to a new-born infant.

Mother’s milk is considered essential because of the presence of the colostrum which is a yellowish fluid secreted by the mother in the initial days of lactation. It has antibodies(IgA) in abundance which is crucial in protecting the infant from picking up infections.

12. List two types of

• granulocytes
• Agranulocytes

 

13. List the preventive barriers that protect the body against microbial bacteria entering the gut through the food consumed. Name the immunity type observed in this case. Following are the barriers:

Lysozyme present in the saliva

Presence of acid (HCl) in the stomach

Mucous coating the epithelial lining in the gut

Innate immunity is observed here.

14. State the principle of vaccination. How can vaccines be used to prevent microbial infections? Write the name of the entity from which the hepatitis B vaccine is synthesized.

It is based on the principle of ‘memory’ of the immune system. In vaccination, a preparation of antigenic proteins or inactivated pathogen is introduced in the body. These antigens generate a primary immune response by generating antibodies with memory B-cells and T-cells. Hence when the vaccinated person is attacked again by the same pathogen, the current T-cells and B-cells recognize the antigen and cause massive production of antibodies and lymphocytes. Yeasts produce the hepatitis-B vaccine.

15. Explain the function of white blood cells  in the body

White blood cells (Leucocytes) are colourless blood cells.. they mainly contribute to immunity and defence mechanism. They protect the body from bacteria and viruses, which are disease-causing organisms.  Unlike red blood cells, the white blood cells contain a nucleus and are larger than the red blood cells. There are fewer white blood cells than white, but there are still about 60 billion in an adult human body.  The bone marrow and lymphatic tissue produce approximately 1 million white blood cells every second.  The white bloods cells  distribute themselves throughout the body by moving through the circulatory system.  When there is an infection within the body, the white blood cells collect in the infected area and attack the foreign organisms.  There are five different types of white blood cells.  The majority of them function to protect the body in some form.  A portion of the white blood cells are what are called phagocytic (monocytes & neutrophils).  They protect the body by fighting the bacterial invaders, and anything which does not belong in the body.  The lymphocytes take care of the production of antibodies and the cells that destroy certain substances and uncommon cells. Usually, there are 7000 to 10 000 white blood cells present per cubic millimeter of blood. When an infection of the blood occurs, the numbers of white blood cells may increase to 30,000 or more per cubic millimeter.  The phagocytic white blood cells eat the bacteria which they encounter.  After these phagocytic cells eat the bacteria some of them die.  This is what pus is when it forms around an infected area.