Study On Immunoadjuvant Effect Of Quil A And PICKCa To DNA Vaccines For FMDV, PCV2-PRRSV

Quil-A is a triterpenoid saponin extracted from the bark of a South America tree(Quillaja saponaria Molina). Quil-A is a surface active saponin which possessesadjuvant properties. First used as an adjuvant in1936by Thibaulu and Richou, it hassince been deployed in veterinary vaccines. Quil-A is freely soluble and stable inwater, is surface active should never be autoelaved, and containes at least5differentQuillaja saponins as judged by HPTLC. PICKCa is a improved adjuvant which wasformulated as a complex of Poly(I:C) which itself is toxic to human and could berapidly hydrolyzed despite its strong adjuvanticity, kanamycin and calcium chloride.Kanamycin is able to neutralize the negative charge of Poly(I:C) as a positivelycharged molecule, rendering Poly(I:C) more stable and resistant to hydrolysis. Andthe calcium chloride facilitates entry of Poly(I:C) into cells. In a word, PICKCa iswell formulated as a stable and safe adjuvant.To evaluate immunoregulation effects of Quil A、PICKCa and the mixture. QuilA、PICKCa and the mixture were injected into the mice and the swine, then the levelof cytokines were detected at the different time. Moreover, the proliferative responseof T lymphocytes was determined after7days. Results: No side effects were observedin the animals. The level of cytokines from the experimental group was significantlyincreases compared with the control group. Furthermore, supplement of adjuvant inthe swine enhanced the proliferative response of T lymphocytes compared with thecontrol group.It is concluded that Quil A and PICKCa are promising vaccine adjuvant.To explore the effect of Quil A as an adjuvant of FMD vaccine. Add Quil A to theFMD vaccine,inject i.m.swine with the prepared FMD vaccines,then the level ofantibody、 cytokines were detected.Moreover, the proliferative response of Tlymphocytes was determined and compared with those of swine immunized byadjuvant-free vaccine. The level of antibody and cytokines from the experimentalgroup were significantly increased compared with the control group. Furthermore,supplement of adjuvant in the swine enhanced the proliferative response of Tlymphocytes. It is concluded that Quil A has the immunopotentiator of FMD vaccine. Porcine reproductive and respiratory syndrome virus (PRRSV) and porcinecircovirus2(PCV2) infections still remain today as the most significant health threatto swine and poses a challenge to current vaccination strategies. The immunogenicityand protective efficiency of DNA vaccines with PICKCa were further evaluated in thepiglets. Compared to other vaccines, detectable specific neutralizing antibody andhigher lymphocyte proliferative responses could be developed in piglets immunizedwith DNA vaccines added PICKCa before virus challenge. Furthermore, moreefficient protection against PCV2-PRRSV challenge was obtained in pigletsimmunized with DNA vaccines added PICKCa, as showed by the balancedbody-temperature fluctuation, milder lung lesions and lower proportion of virus loadin tissues. Our research provides a new method for immunization against these twoviral diseases.