Table 2. Identification of leukemia-associated antigens.
| Antigen | Other name | Patient responses pre-vaccine (N=18) | Patient responses post vaccine (N=19) | Seen in healthy donors (N=19) |
|---|---|---|---|---|
| RHAMM | Hyaluronan-mediated motility receptor | 0 | 5 | 0 |
| DNAJA1 | DnaJ (Hsp40) homolog, subfamily A, member 1 | 0 | 13 | 1 |
| RPS23 | Ribosomal protein S23 (RPS23) | 0 | 2 | 0 |
| EEF1G | Eukaryotic translation elongation factor 1 gamma | 0 | 1 | 0 |
| REPIN1 | Replication initiator 1, transcript variant 4 | 0 | 1 | 0 |
| RHOX | Rhox homeobox family, member 2B (RHOXF2B) | 0 | 4 | 0 |
| MTHFD | Methylenetetrahydrofolate dehydrogenase (NADP+ dependent) 2 | 0 | 1 | 0 |
| USP33 | Ubiquitin specific peptidase 33 (USP33), transcript variant 1 | 0 | 1 | 0 |
| HBG2 | Hemoglobin, gamma G ( HBG2) | 0 | 2* | 0 |
|
Antigens to which antibodies were present at baseline pre-vaccination | ||||
| CDC25C | Cell division cycle 25 homolog C | 1 | 1 | 1 |
| ING3 | Inhibitor of growth family, member 3, transcript variant 1 | 1 | 1 | 2 |
| PRKCSH | Protein kinase C substrate 80K-H | 1 | 2 | 2 |
| NSD1 | Nuclear receptor binding SET domain protein 1, transcript variant 1 | 3 | 3 | 3 |
| HN1L | Hematological and neurological expressed 1-like | 1 | 4 | 3 |
SEREX (serological analysis of recombinant cDNA expression libraries of human tumors with autologous serum) was used to identify the specificity of induced anti-leukemia responses in patients with clinical responses to cancer vaccine therapy. Serum from five clinical responders was screened against a K562 expression library, followed by three rounds of subsequent screening to isolate a monoclonal phage for sequencing. Purified targets from the discovery cohort were sequenced and also used to screen sera from both normal donors (n=19) and pre (n=18, one sample missing)- and post (n=19)-primary vaccination patients. Two patterns of reactivity were observed; antigens to which IgG responses were seen in vaccinated patients but were not seen in either normal donors or patients prior to vaccination (9 of 14 antigens identified), and second, those antigens to which IgG responses were seen in all three groups (5 of 14 antigens identified). *HBG specific IgG responses were observed late in ‘pre-boost samples' only.