What is the main general problem with using mouse monoclonal

What is the main general problem with using mouse monoclonal antibodies as drugs in humans?. How has this problem been reduced in newer Mab drugs?

Solution

Mouse antibodies, being heavy and foreign proteins, are themselves antigenic for human beings. After a certain number of doses, human beings start producing antibodies (\"anti-mouse antibody\") against these therapeutic antibodies of mouse origin and the therapeutic mouse antibodies are rendered ineffective.

Newer Mab drugs are often \'humanized\' to counter this problem. An antibody contains two pairs of peptide chains: one pair each of heavy and light. The constant heavy domain of the mouse antibody, which accounts for the antigenicity of antibodies, is replaced by constant heavy domain of human antibody. Humans do not recognize such humanized antibodies (popularly abbreviated as HAbs) as antigens as effectively and an antibody response (\"anti-humanized mouse antibody\") is not mounted against them.