Alternative Inactivated Poliovirus Vaccines Adjuvanted with Quillaja brasiliensis or Quil-A Saponins Are Equally Effective in Inducing Specific Immune Responses

Abstract

Inactivated polio vaccines (IPV) have an important role at the final stages of poliomyelitis eradication programs, reducing the risks associated with the use of attenuated polio vaccine (OPV). An affordable option to enhance vaccine immunogenicity and reduce costs of IPV may be the use of an effective and renewable adjuvant. In the present study, the adjuvant activity of aqueous extract (AE) and saponin fraction QB-90 from Quillaja brasiliensis using poliovirus antigen as model were analyzed and compared to a preparation adjuvanted with Quil-A, a well-known saponin-based commercial adjuvant. Experimental vaccines were prepared with viral antigen plus saline (control), Quil-A (50 µg), AE (400 µg) or QB-90 (50 µg). Sera from inoculated mice were collected at days 0, 28, 42 and 56 post-inoculation of the first dose of vaccine. Serum levels of specific IgG, IgG1 and IgG2a were significantly enhanced by AE, QB-90 and Quil-A compared to control group on day 56. The magnitude of enhancement was statistically equivalent for QB-90 and Quil-A. The cellular response was evaluated through DTH and analysis of IFN-γ and IL-2 mRNA levels using in vitro reestimulated splenocytes. Results indicated that AE and QB-90 were capable of stimulating the generation of Th1 cells against the administered antigen to the same extent as Quil-A. Mucosal immune response was enhanced by the vaccine adjuvanted with QB-90 as demonstrated by increases of specific IgA titers in bile, feces and vaginal washings, yielding comparable or higher titers than Quil-A. The results obtained indicate that saponins from Q. brasiliensis are potent adjuvants of specific cellular and humoral immune responses and represent a viable option to Quil-A.

Quillaja brasiliensis saponin-based nanoparticulate adjuvants are capable of triggering early immune responses

“…When administered subcutaneously, such adjuvants have shown to trigger powerful immune responses, characterized by the induction of CD4 + and CD8 + T cells, balanced Th1/Th2 cytokine responses, as well as robust and persistent antibody responses 30 , 31 , 35 . In addition, they have proven to be highly effective when delivered via mucosal surfaces 22 , 31 , 34 . However its mechanism of action is still poorly characterized 2 , 31 , 35 .…”

Structural characterisation of new immunoadjuvant saponins from leaves and the first study of saponins from the bark of Quillaja brasiliensis by liquid chromatography electrospray ionisation ion trap mass spectrometry

“…& Tul) Mart (Quillajaceae) is a native tree species in Brazil, Uruguay and Argentina . It has been demonstrated that the aqueous extract and some of the purified fractions obtained from leaves of Q. brasiliensis have immunoadjuvant activity in vaccines against several viruses . One of the fractions studied is Fraction B, which was obtained by solid‐phase extraction on reverse phase C‐18 eluted with a stepwise gradient of methanol and water of aqueous extract …”

“…10 It has been demonstrated that the aqueous extract and some of the purified fractions obtained from leaves of Q. brasiliensis have immunoadjuvant activity in vaccines against several viruses. [11][12][13][14][15] One of the fractions studied is Fraction B, which was obtained by solid-phase extraction on reverse phase C-18 eluted with a stepwise gradient of methanol and water of aqueous extract. 11,16 In our previous investigation, 27 triterpenic saponins were identified from the immunoadjuvant Fraction B, produced from Q. brasiliensis leaves.…”

GERMINATION AND SEEDLINGS DEVELOPMENT OF THE THREATENED SPECIES Quillaja brasiliensis

“…Quillaja brasiliensis contains saponins in its leaves and bark (Reitz, 1996) and has multiple uses. These compounds have adjuvant activity in vaccines, with potential use in the pharmacological industry (Costa et al, 2014;Müller and Schiedeck, 2018). Its wood has high mechanical strength in certain physic-mechanical properties, and it is exploited for construction, carpentry and fuelwood (Carvalho, 2003).…”