Monoclonal Antibodies - Medical Science

Q1:

Preliminary clinical results with a humanized antibody against the interleukin-2 receptor have suggested the

A absence of human immune response against murine proteins (HAMA) response

B presence of HAMA response

C poor recognition of immunoglobulin, Ig constant regions

D all of the above

ANS:A - absence of human immune response against murine proteins (HAMA) response

How can the antibody humanized antibody be produced if human immune response is absent against HAMA protein?