How to calculate the degree to which a mouse-derived antibody is humanized

The degree to which a mouse-derived antibody is humanized can be calculated by comparing its sequence to the corresponding human antibody sequence. Here are the steps to calculate this degree:

1. Obtain the amino acid sequence of the mouse-derived antibody and the corresponding human antibody.

2. Align the two sequences using a sequence alignment tool or software. This will help identify the differences and similarities between the two sequences.

3. Count the number of amino acid residues in the mouse-derived antibody sequence that differ from the corresponding human antibody sequence. These differences can include substitutions, deletions, or insertions.

4. Divide the number of differing residues by the total number of residues in the mouse-derived antibody sequence. Multiply the result by 100 to obtain the percentage of non-human residues.

5. Subtract the percentage calculated in step 4 from 100 to determine the degree of humanization. This will give you the percentage of human residues in the mouse-derived antibody.

For example, if there are 5 differing residues out of a total of 100 residues in the mouse-derived antibody sequence, the percentage of non-human residues would be (5/100) * 100 = 5%. Therefore, the degree of humanization would be 100% - 5% = 95%.

It is important to note that humanization can vary depending on the specific criteria and methods used to engineer or modify the antibody. This calculation provides a general indication of the degree of humanization but may not capture all aspects of the antibody's human-like characteristics.