Monoclonal antibodies 2 Flashcards
uses of monoclonal antbodies
- diagnostic pathology
- in vitro diagnostic asses based on e.g. ELISA, lateral flow assay etc
- affinity purification and characterisation of antigen
there was a limited use of mouse mABs in vivo until fairly recently due to
not having phage display or hybridomal technology
diagnostic pathogly
cytology and histology- ca identify cancerous cells e.g. breast cancer screen-specific abnormalities on antigens of cancerous cells, which can be targeted by specific antibodies
there is a need to
‘humanise’ monoclonal antibodies
why is there a need to humanise monoclonal antibodies
have to be disguised as human- otherwise human immune system will recognise them as foreign and destroy them
if yu put a mouse antibody into a human you have
around 5 days until it will be destroyed
immunogenicity of mouse antibodies in humans
most mAbs used in vivo are of mouse orpine and therefore XENOGENEIC resulting in HAMA reactions-
HAMA
Human antibody mouse antibody
Origin of antibody
mouse origin dimishd their ability to elicit effector mechanisms such as complement, mediated lysis or ADCC
humanisation
use of xenanoantibodies in human patients has proved severley limiting owing to their being foreign proteins- recognised by the patients immune system
strategies adopted to increase the human content of antibodies which have been proven in clinical trial include
1) production of human hybridomas and human B lymphocytes
2) replacement of the constant regions of mouse mAbs (powerful) with those of human antibodies yielding CHIMERIC antibodies
3) replacement of CDRs of human antibody with those of a mouse antibody via CDR gifting to make humanised antibodies
4) production of fully humanised mAbs in transgenic mice
production of human hybridomas
ethical issues and low efficiency
replacement of constant regions of mouse mAbs (powerful) with those of human antibdoies- yielding chimeric antibodies
leaving really important VH/VL parts of the Fab fragments from the mouse
replacement of CDR of human antibody with those of a mouse antibody via CDR grafting to make a
humanised antibody
genetic engineering of monoclonal antibodies
take a human IgG1 antibody, the constant region of a human antibody and replace the VH/VL with that of the mouse- chimeric
- contains some mouse proteins- specific binding - still have all the human parts which will react with complement, ADCC etc
