T-dependent antigens are the antigens which need the help of CD4+ helper T cells for complete activation of B cells. These antigens are mostly soluble or particulate proteins. They produce strong and long lasting immune response. When B cell comes in contact with T-dependent antigen, the antigen binds with B cell receptor (BCR). Then the … Read more
Precipitation Reaction is a reaction in which two soluble substances react together in a solution and form an insoluble solid substance. This insoluble solid substance is called precipitate. In chemical reaction, it occurs when the concentration of dissolved ions becomes more than their solubility limit. This limit is controlled by solubility product constant (Ksp). When … Read more
Immunity is the ability of the body to resist and protect itself from disease causing organisms. It acts against foreign substances like bacteria, viruses, toxins and other antigens. Immunity is the ability of the body to protect itself from infectious diseases and harmful foreign substances. It helps the body to recognize and destroy pathogens like … Read more
The organs of immune system are the organs and tissues which are involved in the defence of body. These organs work together to destroy or neutralize the pathogens. Pathogens may otherwise cause disease in the body. The organs of immune system are generally divided into three categories. These are primary lymphoid organs, secondary lymphoid organs … Read more
Cells of immune system are the protective cells of the body. These cells are concerned with defence against microorganisms, foreign particles, toxins and abnormal cells of own body. Most of these cells are formed in the bone marrow from hematopoietic stem cells. The hematopoietic stem cell gives rise to different blood cells. In immune system, … Read more
Adaptive immunity is the specific immunity which develops after exposure to an antigen. Adaptive immunity is the immunity which is developed after exposure to specific antigen. It is also called acquired immunity. It is a specific defence system of the body. It does not act immediately. It takes some time after first exposure to antigen. … Read more
Active immunity is the immunity in which the body produces its own antibodies and memory cells against a pathogen. It develops slowly after infection or vaccination, but gives long lasting protection. Active immunity is the type of immunity in which the body produces its own antibodies and immune cells against a particular infectious organism. It … Read more
Passive immunity is the type of immunity in which ready-made antibodies are given to a person or animal from outside source. It is not produced by the own immune system of the body. In this immunity the immune system remain passive and only gets protection. It gives very quick protection against infection, toxin or any … Read more
Complement system is an important part of innate immune system. It acts as first line defense against invading pathogens, foreign materials and damaged cells. It helps the body to remove microbes and abnormal cells. It is made up of more than 40 proteins. Most of these proteins circulate in blood in inactive form. When danger … Read more
Complement system is an important part of immune system that helps in the defense of body against invading microorganisms. It is present in the blood and tissue fluid in inactive form. It contains more than 30 plasma proteins which are activated during infection or immune reaction. These proteins are mostly present as inactive proenzymes. When … Read more
