Antigen-Antibody interaction

The word antigen is consequential from antibody cohort it talk about whichever constituent that is gifted of aggravating an immune response (e.g., the manufacture of exact antibody molecules). An antigen (Ag) is gifted of connecting with the precise antibodies molded by its way of life. Typically, antigens are extraneous proteins or their wreckages that enter host physique via a contagion. Nevertheless, the body’s personal proteins might deed as antigens in some circumstances and induce an autoimmune response. Bacteria and viruses comprise antigens, one or the other on their surface, or inside. These antigens can be nearly new to develop vaccines afterward segregation.

Antigens are frequently proteins or polysaccharides and commonly of in elevation molecular weight. Polypeptides, lipids, nucleic acids, and numerous additional materials can also chore as antigens.

Epitope is immunologically energetic constituencies of an antigen (immunogen), quandaries to antigen-specific membrane receptors on lymphocytes or to secreted antibodies. It is disparately acknowledged as antigenic determinants.

Immunoglobulin also known as antibody, is protein in nature, basically protective against foreign substances named as antigens which is produced by our immune system. In order to remove and recognize antigens antibodies plays a crucial role. Antigens are recognized as foreign substances by wide range of substances along with any toxic materials or disease causing pathogens. Whenever the foreign substance enters into the body, it is recognized as foreign substance by the body’s defense mechanism that is the immune system since there are the certain antigens present on the surface of invading molecules that differ from antigens present on the molecules of body. Amongst multiple immune system mechanisms of the body one of the most important is named as antibody production which are produced specifically by the aid of B lymphocytes. The mechanism behind this is that whenever the antigens binds to the receptors of B cell surface, it stimulates the production of the group of identical cells which are clone of those, these mature cells are named as plasma cells and these plasma cells secrete millions of antibiotics into the blood stream which along with fighting with the invading organisms also creates memory cells which works while the same organism invade into the body second time.

There is the specific combination of antigens and antibiotics together which are named as antigen-antibody interaction and are often abbreviated as Ag-Ab reaction. These interactions are the basics of the detection of certain disease causing agents along with certain non-specific organisms for instance enzymes.

The reaction is said to be serological reaction when the reaction occur invitro. There are three phases into which the reaction of antigen and antibody occurs.

1. In the first stage the reaction occur in which antigen-antibody complex forms

2. The visible events occur in the second stage for instance agglutination or precipitation

3. The third or final stage involves the destruction of antigens and the neutralizations of its components.

In the presence of electrolyte that is NaCl, at a particular pH and temperature, the soluble antigens combine with antibodies and an insoluble precipitate of antigen-antibody complex. The precipitin is the name given to antibodies since it is responsible for the precipitation and the reaction is named as precipitation reaction. When a solution containing the particular cation that is a positive ion and is homogenized with another solution which contains the particular anion, which is the negatively charged ion, the insoluble compound formation occur in a solid form which is named as the precipitate. The compounds insoluble in water are usually those having anions for instance hydroxide, sulfide, phosphate and carbonate. If one of these ions are added into the solution which contain any metal cation for instance iron, copper, aluminum etc.

𝐹𝑒2+(𝑎𝑞)+2𝑂𝐻−(𝑎𝑞)→𝐹𝑒(𝑂𝐻)2(𝑆)

𝐴𝑙3+(𝑎𝑞)+𝑃𝑂43−(𝑎𝑞)→𝐴𝑙𝑃𝑂4(𝑆)

Both antigens and antibodies are amino acid complexes and have negative and positive ions distributed among them over surfaces in mutual and specific manner. When the corresponding antibodies are mixed with the antigens, electric repulsion and attraction occur here, the absolute fits are obtained here by means of their electric charges and molecular forms. Basically the precipitation reaction involves the reaction of IgM and IgG antibodies with soluble antigens and lattices forms which is basically the aggregates of interlocking molecules.

In two distinct stages, the reaction of precipitation takes place. Primarily, there is the formation of small antigen-antibody complexes rapidly within seconds, then it is followed by secondary reaction which is basically the slower one, taking from few minutes to hours to complete the procedure, here the lattices formation occur that generates precipitate from the solution. Precipitation reaction do not occur properly until and unless there is the optimal ratio of antigen and antibody. When the either of the component is in excess, no visual precipitation will occur.