Complement system is an ancient part of innate immune system. It acts as first line defence of body against infections. It is present in blood and tissue fluid. It is made up of about 50 plasma and membrane bound proteins. These proteins remain mostly inactive form. After getting proper signal, they become activated one after … Read more
Complement system is an important part of the innate immune system which acts as first line defence against infections. It protects the body from foreign microorganisms and also helps in removing damaged cells and immune complexes. It is present in blood and tissue fluid in inactive form. It is made up of many soluble plasma … Read more
Major Histocompatibility Complex (MHC) molecules are surface proteins of cells. They present antigenic peptide to T cells. It is required for immune recognition of foreign antigen. Expression of MHC molecules is different in different cells. MHC class I molecules are present on almost all nucleated cells. They are absent or very little present on non-nucleated … Read more
Major Histocompatibility Complex (MHC) genes are a group of closely linked genes present in vertebrate DNA. These genes are highly diverse and they play important role in adaptive immune system. In human, this region is known as Human Leukocyte Antigen (HLA) complex. The HLA complex is present on chromosome 6. It contains more than 200 … Read more
Antigen-antibody interaction reaction is a specific binding reaction between an antigen and its corresponding antibody. In this reaction the antibody recognizes the specific part of antigen, which is called epitope. The binding site of antibody is present in the hypervariable region and it is complementary to the epitope. This reaction is very important in humoral … Read more
Antigen is a foreign molecule which is recognized by immune system. It may be protein, polysaccharide, lipid or nucleic acid. It is called antigen because it can generate antibody or bind with antibody. Antigen is mostly found on the surface of bacteria, virus, fungi and parasites. It may also present on normal human cells, cancer … Read more
Antigen Presenting Cells (APCs) are immune cells which capture foreign antigens, process them and present them on their cell surface. The antigen is presented with Major Histocompatibility Complex (MHC) molecules. It is important for activation of T cells. APCs are the link between innate and adaptive immune response. They take antigen from microbes, infected cells … Read more
Immunodiffusion refers to the movement of antigen or antibody within the gel. Add the reactants to the wells. They diffuse to the area of lower/no concentration. A gradient of the reactants’ concentration forms as they diffuse into the gel. Immunoprecipitation takes place in a region with an equivalent concentration of both the antibody and antigen. This is represented by bands.
Flow cytometry is a laser based analytical technique used to measure physical and chemical characters of cells or particles present in a fluid. In this method, cells pass one by one through a laser beam. The scattered light and fluorescence signals are detected and analysed. Flow cytometry is a laser based technique. It is used … Read more
Tumor is also called neoplasm. It is an abnormal solid mass of tissue. It is formed when cells multiply in uncontrolled way or when cells do not die at proper time. Tumor is different from cyst. Cyst is usually filled with fluid or air. But tumor is a solid growth. It has no useful function … Read more
