Very small size
proteoliposomes (VSSP) constitute a complex of very small size
proteoliposomes that includes
proteins,
lipids, CpG and
gangliosides tumor-associated that provides a potential target for
cancer immunotherapy. This compound has been described to stimulate the humoral and cellular response, dendritic cells (DC) activation and differentiation of T-helper cells, specially, in immunocompromised patients with
cancer status. This work deals with the stimulating capacity of the VSSP to reach a humoral response when they are used as a component in a peptidic
vaccine based on the gonadotrophin releasing
hormone (
GnRH). This study was carried out in male Copenhagen rats, which were immunized with 750μg of the
GnRH mimetic
peptide (GnRHm1-TT) with or without the VSSP. The mixtures were always emulsified with the oil adjuvant
Montanide ISA 51. The anti
GnRH seroconversion analysis revealed that the group immunized with the
peptide GnRHm1-TT/VSSP developed a strong anti
GnRH seroconversion. These antibody levels proved to be significant superior to those reached by the use of the GnRHm1-TT
peptide solely emulsified in
Montanide. Post-mortem analysis on the
Testosterone ablation target organs (prostate and testicles) yielded a sudden decrease in their size and weight in respect to the control group. On the other hand, the group submitted to the use of GnRHm1-TT/VSSP, showed a significant difference in the reduction of these target organs in comparison with the group only immunized with GnRHm1-TT adjuvated in
Montanide ISA 51. These values turned to be of p=0.023 and p=0.009 in the prostate and testicles respectively. These findings foreground the VSSP as a useful
immunopotentiator to be used as part of a
GnRH based
vaccine to treat
prostate cancer.