Primary Ab - an antibody that binds to a protein or antigen of study, it has to be from species different from the species of the sample to prevent cross-reactivity

Secondary Ab - an antibody that binds to the Fc region of the primary antibody. Often a conjugate - antibody engineered with an enzyme like HPRO - to cleave the marker (enzyme substrate like TMB). It has to be from a different species that the primary anybody, or it wouldn't recognize it as a forein body.

Antigen- foreign body like a viruse or a bacterium which induce an immune response in the host's body, especially the production of antibodies

Serum - plasma from which clotting factors have been removed

Antiserum - a blood serum containing antibodies against specific antigens

Serial dilution - a method used to stepwise dilute substance into solution with constant dilution factor in each step