Production of monoclonal antibodies : It involves following steps -

(a) First a mouse or other animal is injected with specific antigen. 

(b) The animal will develop an immune response and produces antibodies against the antigen in B-lymphocyte cells in spleen. 

(c) The spleen of the animal is taken out and its B- lymphocyte cells are isolated. 

(d) In the same way, the cells producing bone marrow cancer (myeloma cells) are isolated. These cells should not be able to synthesis their own nutrients. 

(e) Both the myeloma cells and antibody-producing cells are made to fuse together in cultures. The fused cells are named hybridomas.

(f) The unfused myeloma cells are separated from fused myeloma cells by growing them on nutrient deficient medium (needed by myeloma cells). 

(g) The surviving fused myeloma (hybridoma) cells are grown separately and each clone is tested for production of antibody. 

(h) The clones which show positive results are isolated and cultured for large scale production of antibody.