Outline the process of vaccination: (a) weakened pathogens or their antigens are given (b) the antigens stimulate an immune response by lymphocytes which produce antibodies (c) memory cells are produced that give long-term immunity

SouravNovember 3, 2024

Answer

The process of vaccination involves several key steps that stimulate the immune system to provide protection against specific pathogens. Here’s an outline of the vaccination process:

(a) Weakened Pathogens or Their Antigens Are Given

• Types of Vaccines: Vaccines can contain weakened (live attenuated) pathogens, inactivated (killed) pathogens, or specific antigens derived from the pathogen.
  • Live Attenuated Vaccines: These contain a weakened form of the pathogen that cannot cause disease but can still provoke a strong immune response. Examples include the measles, mumps, and rubella (MMR) vaccine.
  • Inactivated Vaccines: These consist of pathogens that have been killed or inactivated so they cannot replicate or cause illness. An example is the inactivated polio vaccine.
  • Subunit Vaccines: These include only parts of the pathogen, such as proteins or sugars, which are sufficient to stimulate an immune response without causing disease. Examples include the hepatitis B vaccine and some pneumococcal vaccines.

(b) The Antigens Stimulate an Immune Response by Lymphocytes Which Produce Antibodies

• Immune Activation: When the vaccine is administered, the immune system recognizes the antigens as foreign invaders. This triggers an immune response involving lymphocytes.
  • B Lymphocytes: These cells are responsible for producing antibodies specific to the antigens present in the vaccine. Antibodies are proteins that can neutralize pathogens and mark them for destruction by other immune cells.
  • T Lymphocytes: In addition to B cells, T cells are activated to help coordinate the immune response and destroy infected cells if necessary.

(c) Memory Cells Are Produced That Give Long-Term Immunity

• Formation of Memory Cells: After the initial immune response, some B and T lymphocytes differentiate into memory cells. These cells persist in the body long after the vaccination.
• Long-Term Protection: Memory cells enable the immune system to respond more rapidly and effectively if exposed to the same pathogen in the future. This results in a quicker and stronger immune response, often preventing illness altogether.