Immuno-Stimulating Peptide Derived from HMGB1 is More Effective Than the N-Terminal Domain of Gp96 as an Endogenous Adjuvant for Improvement of Protein Vaccines.

Up to now, different protein vaccine modalities against human papillomavirus (HPV) have been designed to control cervical cancer. The important issue is to increase their immunogenicity using appropriate adjuvants. Among heat shock proteins (HSPs), glycoprotein 96 (Gp96) and its Nterminal region (NT-gp96) have attracted a specific interest in stimulation of antigen-specific immune responses in vivo. Furthermore, the potency of high mobility group box 1 (HMGB1) protein and its fragment (Hp91) was reported to enhance the desired immune responses against various disorders. In this study, the recombinant (r) HPV16 E7 and rNT-gp96 proteins were generated in bacterial expression system. Mice were vaccinated three times with E7 antigen mixed with Montanide, Hp91, and NT-gp96 as the adjuvant and their preventive and therapeutic efficiencies were evaluated in a murine tumor model. Mice vaccinated with E7 co-delivered by Hp91 peptide induced higher IgG2a and IFN-γ responses in comparison with E7 co-injected with Montanide and NT-gp96 protein suggesting a strong Th1 cellular immune response. The data showed that vaccination with noncovalent rE7 + rNT-gp96 complex delayed the tumor growth as compared to control groups. Mice immunized with rE7 + Montanide and rE7 + Hp91 protected 100% of mice versus 75% survival in groups vaccinated with rE7 + rNT-gp96 after TC-1 tumor challenge. The percentage of tumor free mice was decreased in group immunized with rE7 + rNT-gp96 in therapeutic experiments (~ 50%). These results demonstrated that Hp91 peptide is a safe and strong adjuvant against rNT-gp96 with the potent anti-tumor effects similar to Montanide adjuvant.

Melatonin promotes the cumulus-oocyte complexes quality of vitrified-thawed murine ovaries; with increased mean number of follicles survival and ovary size following heterotopic transplantation.

We have tested the protective effect of melatonin on neonate murine ovarian tissue after vitrification, thawing and heterotopic transplantation into ovariectomized recipient mice. Vitrified ovaries from neonate (CBA x C57Bl/6) F1 hybrid mice were thawed under standard condition with or without the addition of 100 microM melatonin. Following transplantation, melatonin (20 mg/kg/day) or saline solution (physiological saline) was injected i.p. to the treated and non-treated groups for 48 h respectively. Follicle survival and development, together with ovary size followed. Also, vaginal cytology was carried out for monitoring restored puberty. Histological and immunohistochemical studies showed that melatonin could promote the quality of the cumulus-oocyte complexes with uniform distribution of granulosa and stromal cells in the ovarian grafts. Furthermore, the mean follicles survival was improved and the ovary size increased (P< or = 0.001). The overall mean number of follicles entering the next maturation stage dramatically increased. However, the revascularization and restoration of puberty of ovarian grafts were similar between melatonin-treated and control groups. In conclusion, melatonin as a protection from ischemic injury and a reduce oxidative stress, was shown beneficial during the early days of transplantation.