Immunoproteomics

The objective for the immunoproteomics project is to identify cancer related antigens and markers for use in cancer immunotherapy and cancer diagnostics. To this end we exploit that cancer patients develop both humoral and cellular immune responses against proteins expressed by their tumour during disease progression.

Proteins expressed by the tumour may break tolerance and become immunogenic by several means. Autologous antigens may for instance acquire new properties by mutations or aberrant mRNA processing, become expressed in a novel context or show increased expression over a normal baseline level. Thus, the immune responses in the cancer patients reveal molecular events of importance for understanding tumourgenesis, in addition to providing new diagnostics and targets for therapy.

We use a modified version of SEREX (serological expression of cDNA expression libraries). We construct tumour cDNA libraries on filamentous phage and select phages that present tumour cDNA products reacting with the cancer patient IgG. Selected tumour cDNAs are taken further for an automated high-throughput filter immunoscreening (carried out at Affitech AS). The immunoscreening is carried out at the single clone level and the capacity is up to 18,000 single cDNA clones in one screening. We sequence cDNAs reacting with patient antibody and use blast search to find their identity. We thereby obtain a profile of the tumour with respect to the antigen repertoire.

Epitope mapping of identified cDNAs with respect to humoral and cellular epitopes and succeeding large scale screening give information about the cancer specificity and tell us, which cDNAs are relevant for vaccine purposes and as diagnostic markers.

We use a modified version of SEREX (serological expression of cDNA expression libraries) (Alsøe L, et al., 2008). We construct tumour cDNA libraries on filamentous phage (fig. 1) and select phages that present tumour cDNA products reacting with the cancer patient IgG. Selected tumour cDNAs are taken further for an automated high-throughput filter immunoscreening (carried out at Affitech AS). The immunoscreening is carried out at the single clone level and the capacity is up to 18,000 single cDNA clones in one screening. We sequence cDNAs reacting with patient antibody and use blast search to find their identity. We thereby obtain a profile of the tumour with respect to the antigen repertoire. The flow chart for the technology is described in figure 2.

Epitope mapping of identified cDNAs with respect to humoral and cellular epitopes and succeeding large scale screening give information about the cancer specificity and tell us, which cDNAs are relevant for therapeutic purposes and/or as diagnostic/prognostic markers.