Antigens
Antibodies for measles don't work against chickenpox virus because antibody for measles virus can not bind to chickenpox virus. Antibody for a specific antigen should have a shape and structure that is able to fit into this virus. Then it will be able to inhibit the activity of this virus. When a measles vaccine is inserted inside human body, or when someone has measles, the T type lymphocytes (White Blood Cells) detect the type of viruses and then B type lymphocytes produce the antibodies against this specific type of virus. If viruses of the vaccine are alive they will reproduce themselves inside the human body and the number of antibodies against them also increases. Antibodies bind to these viruses and destroy them. Now the virus (of specific disease which needs prevention) which was in the vaccine have been destroyed but the antibodies against this disease viruses are still there and they prevent from the actual disease causing viruses. Antibodies are specific: An infection with the measles virus means that the person makes antibodies only against measles. It doesn't make any antibodies against chickenpox too.
You exhibit Active Immunity when cells encounter anitgens and produce antibodies against them.
Active vaccination produces antibodies against the particular organism. These antibodies kill the invading pathogen and protect the body against the disease.
Antibodies
Pathogens such as bacteria, viruses, fungi, and parasites can respond to antibodies produced by the immune system. Antibodies work by binding to specific antigens on the surface of pathogens, marking them for destruction by other immune cells. This antibody response is a key component of the adaptive immune system's defense mechanism against infections.
In autoimmune diseases, the body makes antibodies that work against its own cells or tissues. Rheumatic diseases (diseases that affect connective tissue, including the joints, bone, and muscle) are also associated with these antibodies.
Antibodies are formed as the defence against antigen or pathogen which is consider as a foreign particle by body against whcih body immune system acts. Antibodies are formed my activated B cells called plasma cell and are made of glycoproteins
antibodies
By definition, antibodies act against particles, proteins, microbes, and viruses. Each antibody has to be a "match" or a "fit" to work against what it is working on. So if you have had chicken pox, you made antibodies to act against it and inactivate it. If you are exposed again, you will not get it. If you get a blood transfusion it must match or your antibodies will inactive it and will cause a reaction that will hurt you. Think of all the things you have come across: different pollen from different plants, different colds, different flu (you have to get a new shot every year as it is different), different vaccines. It just goes on and on.
Individuals with blood type A positive have antibodies against blood type B antigens. This means their immune system reacts against blood from individuals with blood type B if they were to receive a transfusion containing type B blood.
antibodies against dengue virus which appear in the body in response to infection after Ig M antibodies
these are the allo antibodies produced against the foreign cells in a transfused patient usually foun in patients with multiple transfusions