Optimization of cell-wall skeleton derived from Mycobacterium bovis BCG Tokyo 172 (SMP-105) emulsion in delayed-type hypersensitivity and antitumor models

Cell-wall skeleton prepared from Mycobacterium bovis BCG (BCG-CWS) is known as a potent adjuvant and has been shown to possess antitumor activity in many non-clinical and clinical studies. As there are no approved BCG-CWS formulations for cancer therapy, we investigated the potential for cancer immunotherapy of SMP-105, our originally produced BCG-CWS. For optimizing SMP-105 emulsion, we compared the effects of drakeoland squalane-based SMP-105 emulsions on IFN-γ production in rats and evaluated their ability to induce skin reaction in guinea pigs. Both emulsions had the same activity in both experiments. We selected squalane as base material and produced two types of squalane-based formulations (vialed emulsion and pumped emulsion) that can easily be prepared as oil-in-water emulsions. Although the vialed emulsion showed the same pattern of distribution as a usual homogenized emulsion, the pumped emulsion showed more uniform distribution than the other two emulsions. Whereas both emulsions enhanced strong delayed type hypersensitivity (DTH) reaction in a mouse model, the pumped emulsion induced slightly smaller edema. Data on oil droplet size distribution suggest that few micrometer oil droplet size might be appropriate for oil-in-water microemulsion of SMP-105. The antitumor potency of SMP-105 emulsion was stronger than that of some of the launched toll-like receptor (TLR) agonists (Aldara cream, Picibanil, and Immunobladder). Aldara and Picibanil showed limited antitumor effectiveness, while Immunobladder had almost the same effect as SMP-105 at the highest dose, but needed about 10 times the amount of SMP-105. These findings first indicate that SMP-105 has great potential in cancer immunotherapy.

Comparison of the effects of five adjuvants on the antibody response to influenza virus antigen in guinea pigs

Five adjuvants were tested for their effect on the immune response in guinea pigs to the hemagglutinin antigen of influenza virus strain B/Panama. Vaccines containing 924 micrograms of hemagglutinin antigen/ml were prepared at high and low doses of Freund's complete and incomplete adjuvants, Syntex adjuvant, RIBI's adjuvant, TiterMax adjuvant, and aluminum phosphate adjuvant. Responses to these vaccines were compared with those to a control vaccine containing influenza virus B/Panama hemagglutinin antigen and saline. On day 28, vaccines containing the following adjuvant doses had significantly higher titers than the titer for the control: Freund adjuvants at high and low doses, RIBI at high dose, TiterMax at high and low doses, and aluminum phosphate at high dose. On day 42, vaccines containing the following adjuvant doses had significantly higher titers than that for the control: Freund adjuvants at high and low doses, RIBI at high dose, TiterMax at high dose, and aluminum phosphate at high dose. Freund adjuvants at high and low doses, RIBI adjuvant at high dose, and aluminum phosphate at high dose caused significantly greater swelling at the inoculation site than did the control vaccine. TiterMax adjuvant at high and low doses, and aluminum phosphate at low dose caused minor swelling at the inoculation site, but it was not significantly different from the swelling caused by the control vaccine. Syntex adjuvant at high and low doses, RIBI at low dose, and control (saline/antigen) at high and low doses caused no swelling after inoculation. Overall, the high dose of adjuvants caused greater tissue swelling than did the low dose of adjuvants.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of DETOX as an adjuvant for melanoma vaccine

The identification of effective adjuvants is critical for tumor vaccine development. Towards this end, we examined whether the immunogenicity of a melanoma vaccine could be potentiated by DETOX, an adjuvant consisting of monophosphoryl lipid A (MPL) and purified mycobacterial cell-wall skeleton (CWS). Nineteen patients with resected stage III melanoma were immunized with a polyvalent melanoma antigen vaccine (40 micrograms) admixed with DETOX, q3 wks x 4. Seven patients received vaccine + low-dose DETOX (10 micrograms MPL + 100 micrograms CWS) and 12 received vaccine + high-dose DETOX (20 micrograms MPL + 200 micrograms CWS). A non-randomized control group of 35 patients was treated similarly with 40 micrograms vaccine + alum. One week after the fourth vaccine immunization, melanoma antibodies were increased over baseline in 7/7 (100%) patients treated with vaccine + low-dose DETOX, 8/12 (67%) patients treated with vaccine + high-dose DETOX, and in 4/19 (21%) of vaccine + alum patients. For the entire DETOX group, the antibody response rate was 15/19 (79%) compared 4/19 (21%) in the alum group (p < 0.001). In contrast, a strong delayed-type hypersensitivity (DTH) response (> or = 15 mm increase in DTH response over baseline) was induced in 50% of the entire DETOX group versus in 47% of the alum group. Median disease-free (DF) survival for the entire DETOX group was 17.8 months compared with 32.1 months in the alum group (p < 0.05). In conclusion, DETOX markedly potentiated antibody but had little effect on DTH responses to melanoma vaccine immunization. It did not appear to improve disease-free survival in comparison to alum in this non-randomized study.

Evaluation of several adjuvants as alternatives to the use of Freund's adjuvant in rabbits

In three experiments we evaluated several types of adjuvants as an alternative to Freund's adjuvant (FA). In the first experiment three adjuvant preparations (a water-in-oil emulsion (Specol), a combination preparation of monophosphoryl lipid A + trehalose dimycolate + cell wall skeleton and a non-ionic block polymer surfactant (TiterMax)) were evaluated. The adjuvants were combined with three different types of weak immunogenic antigens (synthetic peptide, glycolipid and particulate antigen) and administered following the intramuscular and subcutaneous route. The evaluation was based on clinical, pathological and immunological parameters. The animals did not appear to be severely or chronically impaired by the experiment. After injection of the RIBI adjuvant, side effects of the same severity as with FA were induced, while low antibody titers were produced. TiterMax caused few side effects, while antibody responses were very low. In comparing Specol and FA, Specol had far fewer adverse effects than FA. However, Specol had immunostimulating properties of the same level as FA. In the second experiment, the effect of injected volume of FA on side effects and antibody titer was studied. Immunization of rabbits with a total of 0.5 ml FA at different sites does not seem to increase the immune response when compared with the immune response seen after injection of 0.5 ml FA at one site. However side effects were seen in all the animals. In the third experiment, the side effects following intradermal (i.d.) injection of the adjuvants were studied. After i.d. injection of FA or RIBI, undesirable effects were found. No side effects occurred after i.d. injection of Specol or TiterMax. From the studies it is concluded that Specol is an alternative to FA for hyperactivation of the immune response in rabbits.