Immunization is what type of immunity

Antibodies are disease-specific. For example, measles antibody will protect a person who is exposed to measles disease but will have no effect if he or she is exposed to mumps. Active Immunity results when exposure to a disease organism triggers the immune system to produce antibodies to that disease. Active immunity can be acquired through natural immunity or vaccine-induced immunity. Either way, if an immune person comes into contact with that disease in the future, their immune system will recognize it and immediately produce the antibodies needed to fight it.

Active immunity is long-lasting, and sometimes life-long. Passive immunity is provided when a person is given antibodies to a disease rather than producing them through his or her own immune system. Such links are provided consistent with the stated purpose of this website. Need larger text? Immunology Basics What is Immunity?

Innate Immunity Innate immunity is the immune system that is present when you are born. Adaptive Immunity Adaptive immunity is protection that your body builds when it meets and remembers antigens, which is another name for germs and other foreign substances in the body.

There are two types of adaptive immunity: active and passive. Active Immunity - antibodies that develop in a person's own immune system after the body is exposed to an antigen through a disease or when you get an immunization i.

This type of immunity lasts for a long time. Passive Immunity - antibodies given to a person to prevent disease or to treat disease after the body is exposed to an antigen.

Passive immunity is given from mother to child through the placenta before birth, and through breast milk after birth. It can also be given medically through blood products that contain antibodies, such as immune globulin. This type of immunity is fast acting but lasts only a few weeks or months. How vaccines work with the immune system Vaccines provide active immunity to disease. Here is how a vaccination works: The vaccine is administered. It contains antigens to a specific disease.

However, these responses are not specific to a particular pathogenic agent. Instead, the innate immune cells are specific for conserved molecular patterns found on all microorganisms. This prevents the innate immune system from inadvertently recognizing host cells and attacking them. However, this prevents the innate immune responses from improving their reactions with repeated exposure to the same pathogenic agent. In other words, the innate immune system does not have memory.

The protective defenses of the innate immune system begin with the anatomic barriers such as intact skin and mucous membranes which prevent the entrance of many microorganisms and toxic agents. The skin also has an acidic environment of pH which retards the growth of microorganisms. In addition, the normal microorganisms or flora, which inhabit the skin and mucous membranes compete with other microorganisms for nutrients and attachment sites. Further, the mucus and cilia on the mucous membranes aid in trapping microorganisms and propelling them out of the body.

Next, the innate immune system includes such physiologic barriers as the normal body temperature, fever, gastric acidity, lysozyme, interferon, and collectins. The normal body temperature range inhibits a variety of microorganisms; and, the development of a fever can further inhibit many of these pathogenic organisms.

The gastric acidity of the stomach is also quite effective in eliminating many ingested microorganisms. Lysozyme, which is a hydrolytic enzyme found in tears and mucous secretions, can cleave the peptidoglycan layer of the bacterial cell wall thus lysing the microorganism. They can directly kill certain pathogenic microorganisms by disrupting their lipid membranes or indirectly by clumping microorganisms to enhance their susceptibility to phagocytosis.

The complement pathways are also a part of the defensive measures of the innate immune system. There are three complement pathways. The alternative or properdin pathway is triggered by the deposition of complement protein, C3b, onto microbial surfaces and does not require antibodies for activation. The third pathway, the lectin pathway, is triggered by the attachment of plasma mannose-binding lectin MBL to microbes and does not require antibodies for activation.

These three pathways merge into a common pathway which leads to the formation of the membrane attack complex that can form pores in the membrane of targeted cells. The complement pathways are also integral in the opsonization or increased susceptibility of particulate antigens to phagocytosis and in triggering a localized inflammatory response. The inflammatory response is another essential part of the innate immune response.

The inflammatory response is the body's reaction to invasion by an infectious agent, antigenic challenge, or any type of physical damage. The inflammatory response allows products of immune system into area of infection or damage and is characterized by the cardinal signs of redness, heat, pain, swelling, and loss of function.

In addition to the anatomic and physiologic mechanisms, there are also Pattern recognition receptors or PRRs which contribute to the innate immune response. Pattern recognition receptors are not specific for any given pathogen or antigen, but can provide a rapid response to antigens.

PRRs are classified as membrane proteins because they are associated with the cell membrane; and, they can be found in all the membranes of the cells in the innate immune system. Although there are several hundred varieties, all the genes of the PRRs are encoded in the germline to ensure limited variability in their molecular structures.

These antigens are produced by microbal cells and not by human cells. Finally, the mononuclear phagocytes and granulocytic cells are also important to the innate response and help link the innate immune response to the adaptive immune response. Mononuclear phagocytes include monocytes which circulate in the blood and macrophages which are in the tissues. Monocytes and macrophages are highly important in antigen presentation, phagocytosis, cytokine production, and antimicrobial and cytotoxic activities.

Upon maturity of the monocytes, the monocytes circulate in the blood for approximately 8 h, then migrate into the tissues and differentiate into specific tissue macrophages or into dendritic cells. There are several types of dendritic cells which are involved in different aspects of immune functions. Many dendritic cells are important in presenting antigen to T-helper cells. However, follicular dendritic cells are found only in lymph follicles and are involved in the binding of antigen—antibody complexes in lymph nodes.

Neutrophils are highly active phagocytic cells and generally arrive first at a site of inflammation. Eosinophils are also phagocytic cells; however, they are more important in resistance to parasites. Basophils in the blood and mast cells in the tissues release histamine and other substances and are important in the development of allergies.

The innate system may be able to eradicate the pathogenic agent without further assistance from the adaptive system; or, the innate system may stimulate the adaptive immune system to become involved in eradicating the pathogenic agent. In contrast to the innate immune system, the actions of adaptive immune system are specific to the particular pathogenic agent. This response will take longer to occur than the innate response.

However, the adaptive immune system has memory which means that the adaptive immune system will respond more rapidly to that particular pathogen with each successive exposure. These are the two arms of the adaptive immune system. The B—cells and antibodies compose humoral immunity or antibody-mediated immunity; and, the T-cells compose cell-mediated immunity.

As a note, natural killer cells are also from the lymphocyte lineage like B—cells and T-cells; however, natural killer cells are only involved in innate immune responses. The first arm of the adaptive immune system is humoral immunity, functions against extracellular pathogenic agents and toxins. B—cells are produced in the bone marrow and then travel to the lymph nodes.

Unlike T-cells, B—cells can recognize antigens in their native form which means that B—cells can recognize antigens without requiring that the antigen be processed by an antigen-presenting cell and then presented by a T-helper cell. Examples of these T-independent antigens include lipopolysaccharide, dextran, and bacterial polymeric flagellin. These antigens are typically large polymeric molecules with repeating antigenic determinants.

These antigens can also induce numerous B—cells to activate; however, the immune response is weaker and the induction of memory is weaker than with T-helper cell activation.

In contrast, activation of B—cells with T-helper cell activation results in a much better immune response and more effective memory. This long-term, effective immune response is the type of reaction that is the goal of immunizations. This process then stimulates the B—cell s to mature into a plasma cell s which then begins production of the particular antibody with the best corresponding fit to the antigen.

From these stimulated B-cells, clones of B-cells with the specificity for the particular antigen will arise. These cells may become plasma cells producing antibodies or memory cells which will remain in the lymph nodes to stimulate a new immune response to that particular antigen.

This occurs during the primary immune response when the immune system is first exposed to a particular antigen. This process of clonal selection and expansion will take several days to occur; and, primarily involves the production of IgM. IgM is the first antibody produced during a primary immune response. As the immune response progresses, the activated plasma cells will begin producing IgG specific to the particular antigen. Although IgM is the first antibody produced and is a much larger antibody, IgG is a better neutralizing antibody.

IgG binds more effectively to the antigen and aids in opsonization. As a note, other antibodies can be produced by plasma cells. IgD is primarily found as a receptor bound to the surfaces of mature B—cells.

While, IgA is the antibody found in secretions such as mucous, saliva, tears, and breast milk; and, IgE is the antibody involved in allergic reactions and parasitic infections. However, the most important antibody for vaccines is IgG. With the memory cells that have been produced with the primary immune response, any succeeding exposures to the antigen will result in a more rapid and effective secondary immune response.