If we fuse conserved region of antibody from mouse to a variable region from rat will the fusion antibody work with similar efficiency? Or is there any other method to murinise the sequence of Antibody raised in rat against a human protein. Actually I want to express an antibody gene in mouse which was initially raised in rat.. Please friends help me. Thank you so much in advance.
Generally yes, what you are describing would be called a "chimeric antibody", this is the simplest way murine antibodies are "humanized" for therapeutic applications in humans.This reduces immunogenicity and makes sure that the antibody will be able to interact with human Fc receptor and complement. This usually has no effect on antigen binding affinity and specificity.
To minimize antigenicity, it is also possible to adapt the V-domain sequences, changing the framework sequences of the V-domains to the closest human sequences. This is more tricky, as you are producing chimeric domains, and my need to preserve some Non-CDR residues in the murine sequence to retain the full affinity.
Generally yes, what you are describing would be called a "chimeric antibody", this is the simplest way murine antibodies are "humanized" for therapeutic applications in humans.This reduces immunogenicity and makes sure that the antibody will be able to interact with human Fc receptor and complement. This usually has no effect on antigen binding affinity and specificity.
To minimize antigenicity, it is also possible to adapt the V-domain sequences, changing the framework sequences of the V-domains to the closest human sequences. This is more tricky, as you are producing chimeric domains, and my need to preserve some Non-CDR residues in the murine sequence to retain the full affinity.
Many thanks Annemarie for your answer. Did you do this kind of experiment or do you have any idea whether this s a successful experiment and is there any good publication on this...
If you suggest me some published literature on this it will be a great help.
Best regards
Personally, I did not work too much with full immunoglobulins, but mostly worked on the re-engineering of antibody fab and scFv fragments and the design of synthetic antibody libraries for phage display selection, and occasionally designed humanized variable domains for other labs.
There is a huge amount of literature on murine-human antibody chimeras ( http://scholar.google.ch/scholar?start=10&q=chimeric+antibodies&hl=de&as_sdt=0,5 ). To judge from the germline repertoire, murine and rat repertoire are quite similar in their compatibility to the human repertoire, and should be quite compatible to each other.
For a detailed answer, I would need to know what you want to achieve. I assume you plan to use your antibodies in a murine disease model - are you mainly worried about the ability of your antibodies to elicit antibody-dependent cell-mediated cytotoxicity and complement-mediated cytolysis in some desease model in mouse, or about the immunogenicity of murine antibodies in rat?
Annemarie is definitely correct. If your murine model requires repeat dosing and you would like to have Fc receptor engagement that is correct for the mouse, then chimerising the rat v-domains onto a mouse Fc like mouse IgG2a should be ideal. Having said that, if the model is short and only involves a few doses, with no need for Fc effector function readouts/involvement, then you may not need to change the antibody at all. For example, we regularly will use fully human antibodies in short term mouse models. If, however, you are talking about a long-term chronic dosing model like autoimmune models etc, then chimerisation onto mouse would be essential, as anti-Rat antibody responses could ruin your experiment.
Dear Annemarie and Dear William,
This is an awesome help. Actually, I am worried for both as asked by Annemarie....Basically, I am trying to develop an autoimmune disease model of mouse so I need to use the mouse for long term...And that is why I am planning to make the chimera of rat variable region with mouse conserved region (Fc) and I am worried whether my chimeric antibody will be functional or not... But I am really thankful to u, its a very good discussion...Best regards
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