Vaccinology. Antigens are foreign substances that stimulate the immune system to produce antibodies. Antigens can be in the form of fungi, bacteria or viruses that cause diseases and infections. Allergens such as pollen, dust, gluten, and milk that cause allergic reactions are also considered antigens. These foreign substances can also be introduced through blood transfusions forcing the body to stimulate the production of antibodies. Different antigens have distinct surface features resulting in specific responses.
Antigens are classified according to their various immune responses. There are complete antigens, incomplete antigens, T-independent, and T dependent antigens. Complete antigens are substances that have the ability to stimulate the formation of antibodies and produce a specific and evident reaction with the specific antibody. Incomplete antigens such as haptens are substances that are incapable of stimulating the production of antibodies by themselves but can stimulate the production of antibodies when they combine with larger elements such as proteins. T-independent antigens are substances that stimulate the B cells to produce antibodies without help of T cells. T-independent antigens are mostly polysaccharide in nature. Some examples of T- independent antigens include flagella and pneumococcal polysaccharide. T-dependent antigens are substances that are incapable of stimulating the production of antibodies without the help of T cells (King Saud University). T-dependent antigens are mostly protein in nature. Examples of T-dependent antigens include microbial proteins.
Vaccinology. Antigens, invading pathogens and microbes, are regarded as a threat by the immune system resulting in immune response stimulation. Antigens are found on the surface of the microbe or pathogen and are unique to that microbe or pathogen. For instance, a tuberculosis bacterium has different antigens on its surface from whooping cough bacteria. When an antigen enters the body, the body’s immune system responds by producing antibodies against it. The antibodies which are Y shaped are produced to fight off the antigen. The lymphocytes, a type of white blood cells, identify the antigen as an invader and stimulate the production of antibodies specific to that antigen. Every antibody has a unique binding site shape which links with the specific shape of the foreign matter. The antibodies destroy the foreign substances which are then consumed by the macrophages. White blood cells also destroy toxins which are produced by bacteria that invade the body. Some of the illnesses where the bacteria secrete toxins include diphtheria and tetanus. The white blood cells destroy the toxins by producing antitoxins. The immune response if the final line of defense. Once the pathogens and microbes have been destroyed by antibodies, the immune response ends.
Additionally, the immune system protects the body from subsequent infections and diseases by producing memory cells that are specific to the antigen. When an antigen enters the body for the first time, the individual might experience some symptoms of the disease as the immune system produces antibodies to fight the foreign substances. After fighting off the antigen, the body produces memory cells that are specific to that antigen. The memory cells recognize the pathogen or microbe which caused the illness and quickly produce the correct antibodies when the body is exposed to the same pathogen or microbe. The subsequent attacks by the same pathogens or microbes stimulate the immune memory to produce a large amount of the antibodies produced the first time. The rapid immune response quickly destroys the pathogen or microbe preventing the occurrence of symptoms of disease after exposure to an antigen. This way, the individual is considered to have developed immunity to the antigen. The immune memory explains how individuals develop immunity to disease such as chicken pox after the first exposure.
Further, in immunization, antigens are introduced into the body to make a person immune to a disease. The antigens are introduced to the body through an injection to stimulate the production of antibodies. The vaccines used contain antigens which stimulate the B lymphocytes of the immune system to produce plasma cells which produce disease specific antibodies. This is considered the primary response. The B cells then become the memory cells which identify and recognize subsequent exposure to the specific antigen. The memory cells help in the quick and intense production of antibodies which work to eliminate the disease by fighting the antigens. This is considered the secondary response in immunization. While exploring the effectiveness of smallpox vaccination, scholars argue that an individual’s immunity can last up to 12 years in the presence of CD4+ T cell memory and up to 15 years in the presence of CD8+ T cell memory following vaccination. Immunization against small pox using hydrogen peroxide is considered effective because it protects the body against chronic viral infections. The immunization helps in the inactivation and destruction of lethal antigens.
Moreover, the research that is carried out on antigens helps in understanding vaccines and facilitates vaccine development and production. The function of vaccines is to enable the body’s immune system to fight and defend the body against diseases. When inoculated, the vaccine triggers the immune system the same way the body responds to an exposure to a virus. The immune system identifies the pieces of the weakened antigen in the vaccine as a foreign substance. The immune system then responds by producing antibodies that identify and destroy the antigens. There are two main types of vaccines; non-adjuvanted vaccine and adjuvanted vaccine. The non-adjuvanted vaccine has the antigen as the main component while the adjuvanted vaccine has two main components; the adjuvant and the antigen. The adjuvant is added to the vaccine to enhance the immune response of the vaccine. Vaccines are produced using eggs, mammalian cells and using investigational methods such as insect, plant cells or bacteria cultures (Laere et al 1). The investigational methods of vaccine production are still being actively investigated by scholars. Research on antigens produces knowledge of effective manufacturing methods to enhance the effectiveness of vaccines.
Furthermore, research identifies the major challenges in designing vaccines for antigens. Some of the challenges that scholars face in developing vaccines include the antigen’s ability to evade the immune system, the antigenic complexity of the invaders and the cost of developing vaccines. Lahariya (491) argues that the number of antigens in immunization programs varies from country to country. However, antigens against common diseases such as tetanus, poliomyelitis, hepatitis B, diphtheria and pertussis are found in many immunization programs around the world. Although the current immunization protocols have been considered effective in defending the body against disease, scientists foresee challenges in the future regarding some pathogens. Therefore, scholars need to understand the role of specific pathogens in altering the host immune response.
Vaccination has been proven to be one of the most effective methods of protecting the body against disease. There are numerous antigens against which vaccines are available. Many more antigens continue to be targeted in the research and development of the vaccines. When the antigens enter the body, the immune system responds by producing antibodies to fight the antigen. During the immune response, the body develops memory cells that help prevent subsequent attacks by the same antigen. When developing vaccines, a weakened antigen is introduced into the body to trigger an immune response to protect the body from future attacks by the same antigen.