Vaccination and Immunity

Innate immunity refers to non-specific defense mechanisms that are present in the human body by birth to protect against the antigen. These mechanisms include physical barriers such as skin, chemicals in the blood and immune system cells that attack foreign cells in the body.

Passive immunity is the transfer of active humoral immunity of ready-made antibodies (exogenous). Passive immunity can occur naturally, when maternal antibodies are transferred to the fetus through the placenta, and it can also be induced artificially when high levels of antibodies specific to a pathogen or toxin are transferred to non-immune persons through blood products that contain antibodies. Passive immunization can be provided when people cannot synthesize antibodies, and when they have been exposed to a disease against which a person is not immunized.

Vaccination is the administration of antigenic material (a vaccine) to stimulate an individual's immune system to develop acquired immunity to a pathogen. Upon administration of attenuated or inactivated antigen (vaccine), the antibodies are produced by plasma cells and memory cells are activated. When the same antigen attacks the person in future, the memory cells recognize the antigen and promotes phagocytosis.

Active immunity is the induction of immunity after exposure to an antigen. Antibodies are created by the recipient and may be stored permanently due to the activation of memory cells which recognizes the same antigen in future and destroy them. Active immunity can occur naturally when a microbe or other antigen is received by a person who has not yet come into contact with the microbe and has no pre-made antibodies for defence.

• Acquired immunity is the immunity obtained either from the development of antibodies in response to exposure to an antigen, as from vaccination or an attack of an infectious disease or from the transmission of antibodies, as from mother to fetus through the placenta or the injection of antiserum.
  
• Active acquired immunity results from the development of antibodies in response to an antigenic stimulus, as from exposure to an infectious disease or through vaccination.
• Hence, resistance developed in an individual as a result of antigenic stimulus is due to Active acquired immunity.

• Gammaglobulin is a class of globulins which are immune molecules that are produced by the immune system in response to the invasion of the body of agents that are perceived by the system as being foreign. Most significant globulins are immunoglobulins.
  
• Artificially acquired passive immunity is a short-term immunization by the injection of antibodies such as gamma globulin that are not produced by the recipient's cells.
  
• Hence, a person injected with gammaglobulin against hepatitis B is artificially acquired passive immunity.

Artificially acquired passive immunity is a short-term immunization achieved by the transfer of antibodies, which can be administered in several forms such as human or animal blood plasma or serum. Antivenine is an antisera which is obtained from the snake poison and it is transferred to the person with snake bite. It is used to provide immediate immunity in case of emergency.

• When the immune system is activated due to the viral infection or other immune response the white blood cells in our body produces Interferons (are a group of proteins called cytokines). Interferons inhibit viral multiplication
• The name of the interferons comes from their ability to interfere with the production of new virus particles. Interferons do not directly kill viral or cancerous cells; they boost the immune system response and reduce the growth of cancer cells by regulating the activity of several genes that control the secretion of numerous cellular proteins that affect growth.
• Hence cytokine that provides nonspecific immunity against viruses is Interferon.
• So, the correct answer is 'Interferons'.

The acquired immune system, also known as the adaptive immune system is a subsystem of the overall immune system that is composed of highly specialized, systemic cells and processes that eliminate pathogens or prevent their growth. Acquired immunity creates immunological memory after an initial response to a specific pathogen, and leads to an enhanced response to subsequent encounters with that pathogen. Acquired immunity distinguish between self and non-self and produce antibodies against the non-self antigen.

• Passive immunity is the transfer of active humoral immunity of ready-made antibodies (exogenous) or preformed antibodies. Passive immunity can occur naturally, when maternal antibodies are transferred to the fetus through the placenta, and it can also be induced artificially when high levels of antibodies specific to a pathogen or toxin are transferred to non-immune persons through blood products that contain antibodies. People administered with preformed antibodies get 'Passive immunity'.
• So, the correct answer is 'Passive immunity'.

Polymorphonuclear leucocytes (neutrophils) and monocytes are key components of the cellular barrier in the innate immune system, which phagocytose pathogens.

Artificially acquired passive immunity explains this form of protection. When performed antibodies are directly injected into the body, it is known as artificial passive immunity. It provides the quick immune response. In case of snake bites, the injection which is given to the patients, contain performed antibodies against snake venom. This type of immunisation is passive immunisation.

Passive immunity involves the transfer of pre-formed antibodies (serum, gamma-globulin). Attenuated microorganisms are used in vaccines to stimulate the body to produce its own antibodies, which is the definition of active immunity.

BCG (Bacillus Calmette-Guerin) vaccine is recommended to be administered as soon as possible after birth to provide early protection against tuberculosis.