Sequential immunogene therapy with interleukin-12- and interleukin-15-engineered neuroblastoma cells cures metastatic disease in syngeneic mice.
OBJECTIVE
To investigate the potential synergistic effects of Neuro2a neuroblastoma cells engineered with IL-12 and/or IL-15 genes in improving survival of syngeneic mice bearing neuroblastoma metastatic disease.


METHODS
Neuro2a cells engineered with interleukin (IL)-12 (Neuro2a/IL-12), IL-15 (Neuro2a/IL-15), or both cytokines (Neuro2a/IL-12/IL-15) were injected s.c. in syngeneic A/J mice challenged i.v. with Neuro2a parental cells (Neuro2apc) using different schedules of administration in either preventive or therapeutic settings.


RESULTS
A single injection of Neuro2a/IL-12 or Neuro2a/IL-15 cells induced resistance to a subsequent i.v. Neuro2apc challenge in 45% and 28% of mice, respectively. Neuro2a/IL-12/IL-15 cells protected 28% of mice, showing no synergistic effect. However, sequential vaccination with Neuro2a/IL-12 (day -30) followed by Neuro2a/IL-15 (day -15) protected 71% of mice from subsequent challenge with Neuro2apc. A single dose of Neuro2a/IL-12 prolonged the mean survival time of mice bearing established metastatic neuroblastoma from 21 +/- 3 to 46 +/- 27 days but failed to cure mice, whereas Neuro2a/IL-15 or Neuro2a/IL-12/IL-15 were ineffective. However, sequential vaccination with Neuro2a/IL-12 (day +3) followed by Neuro2a/IL-15 (day +13) cured 43% of mice as assessed by histologic analysis of different organs from long-term surviving mice. CTL activity against Neuro2apc cells was observed in splenocytes from treated mice, and CD8(+) T-cell depletion abrogated the therapeutic effect of vaccination.


CONCLUSIONS
Sequential vaccination with IL-12- and IL-15-engineered neuroblastoma cells induced optimal preventive and therapeutic effects, which may be related to the Th1 priming effect of IL-12 followed by the enhancement of CD8(+) T-cell responses and their maintenance mediated by IL-15.
Croce
Michela
M
Laboratory of Immunopharmacology, Istituto Nazionale per la Ricerca sul Cancro, Largo Benzi 10, 16132 Genoa, Italy.
Meazza
Raffaella
R
Orengo
Anna Maria
AM
Radić
Luana
L
De Giovanni
Barbara
B
Gambini
Claudio
C
Carlini
Barbara
B
Pistoia
Vito
V
Mortara
Lorenzo
L
Accolla
Roberto S
RS
Corrias
Maria Valeria
MV
Ferrini
Silvano
S
D000818:Animals; D018414:CD8-Positive T-Lymphocytes / Q000378:metabolism; D003602:Cytotoxicity, Immunologic; D004195:Disease Models, Animal; D005260:Female; D005818:Genetic Engineering; D007167:Immunotherapy; D018664:Interleukin-12 / Q000235:genetics / Q000627:therapeutic use*; D019409:Interleukin-15 / Q000235:genetics / Q000627:therapeutic use*; D051379:Mice; D008805:Mice, Inbred A; D009447:Neuroblastoma / Q000235:genetics / Q000556:secondary / Q000628:therapy*; D015996:Survival Rate; D014407:Tumor Cells, Cultured
D019409:Interleukin-15; D018664:Interleukin-12