Recombinant vaccinia/fowlpox NY-ESO-1 vaccines induce both humoral and cellular NY-ESO-1-specific immune responses in cancer patients

Abstract

NY-ESO-1 is a cancer/testis antigen expressed in a range of human malignancies, and a number of vaccine strategies targeting NY-ESO-1 are being developed. In the present study, the safety and immunogenicity of recombinant vaccinia-NY-ESO-1 and recombinant fowlpox-NY-ESO-1 were analyzed in a series of 36 patients with a range of different tumor types. Each construct was first tested individually at two different dose levels and then in a prime-boost setting with recombinant vaccinia-NY-ESO-1 followed by recombinant fowlpox-NY-ESO-1. The vaccines were well tolerated either individually or together. NY-ESO-1-specific antibody responses and/or specific CD8 and CD4 T cell responses directed against a broad range of NY-ESO-1 epitopes were induced by a course of at least four vaccinations at monthly intervals in a high proportion of patients. CD8 T cell clones derived from five vaccinated patients were shown to lyse NY-ESO-1-expressing melanoma target cells. In several patients with melanoma, there was a strong impression that the natural course of the disease was favorably influenced by vaccination.

Fig. 1.

Development of NY-ESO-1 serum antibody and specific CD8 and CD4 T cell responses in individual patients immunized with rV/rF-NY-ESO-1 vaccine. NY-ESO-1 (pink), LAGE-1 (blue), MAGE-3 (yellow), MAGE-4 (green), and p53 (light blue) serum antibody was assessed by ELISAs before and after vaccination. OD values at a serum dilution of 1:400 are shown. Arrows indicate day of vaccine. CD8 and CD4 T cell responses against NY-ESO-1 epitopes were assessed in ELISPOT assays. Bars show the number of specific spots per 25,000 effector T cells. CD8 T cell responses in HLA-A2-positive patients (indicated by asterisks) are shown tested with the representative NY-ESO-1 p157–165 epitope, and CD8 T cell responses in non-HLA-A2 patients are shown tested with overlapping NY-ESO-1 18- to 20-mer peptides (colored bars). CD4 T cell responses were tested with 18- to 20-mer peptides (colored bars). T cell responses were considered positive when they were at least threefold higher than the background. Pat., patient.

Fig. 2.

NY-ESO-1 epitopes (the x axis indicates the position of the first amino acid of each 20-mer or 18-mer peptide) recognized by CD8 T cells of 23 evaluable patients grouped into categories I–IV before and after vaccination. (a) CD8 epitopes are clustered around NY-ESO-1 regions p81–110 and p151–170. In patients marked with an asterisk, T cell responses were assessed by presensitization with NY-ESO-1 p157–165 only. All other patients were monitored by presensitization of effector cells with Ad2/ESO and, in addition, with NY-ESO-1 p157–165 in HLA-A2-positive patients. (b) CD4 epitopes show a broader distribution spanning NY-ESO-1 regions p43–138; additional epitopes recognized less frequently are located between p139–180. Pt., patient.

Fig. 3.

Specific cytotoxicity of CD8 T cell clones obtained from patient 22 (category II) and patient 19 (category III). Clones were generated by presensitization of postvaccine T cells with Ad2/ESO followed by limiting dilution and restimulation with the relevant NY-ESO-1 peptide epitope recognized after the initial stimulation. The distinct specificity of the T cell clones reflects recognition of different NY-ESO-1 epitopes (p91–110 in patient 22 and p71–90 in patient 19). Cross-reactivity against naturally processed NY-ESO-1 in tumor cells is shown by the specific reactivity against different NY-ESO-1-positive tumor cell lines (SK-Mel-52, Mel66, NW-Mel-2231) and the lack of reactivity against NY-ESO-1-negative tumor cell lines (NW-Mel-8, NW-Mel-145, SK-Mel-61) and K562. The effector-to-target cell ratio is 3:1 for patients 19 and 22.