Pairwise titers:
Serum A | Serum B | |
Virus A | 2560 | 80 |
Virus B | 160 | 1280 |
Convert to distances, based on 2-fold drops in titer from highest titer in a column.
Serum A | Serum B | |
Virus A | 0 | 4 |
Virus B | 4 | 0 |
Position elements in 2D space so that distances are recapitulated.
Serum A | Serum B | Serum C | Serum D | |
Virus A | 2560 | 80 | 640 | 640 |
Virus B | 160 | 1280 | 640 | 640 |
Virus C | 320 | 160 | 5120 | 640 |
Virus D | 640 | 320 | 1280 | 2560 |
Hints: Titers won't match perfectly, but will match well. All points can fit in previous slide's grid.
"Humans vaccinated against influenza produce antibodies against the immunizing antigen, but produce antibodies of higher titer against the antigen that was their first childhood experience of influenza, even if that strain happend to be absent from the vaccine."