These results suggest that switching from Alum to Quil A would be beneficial for AD patients because anti-A antibody production was enhanced without changing the initially generated and likely beneficial Th2-type humoral response. Keywords: Alzheimers disease (AD), Epitope PD166866 vaccine immunization, Th1 and Th2 PD166866 adjuvants 1. epitope vaccine composed of self B cell epitope A1C15 and foreign T cell epitope PADRE (PADRE-A1C15-MAP). Formulated in Quil A, this vaccine resulted in significantly higher anti-A antibody reactions in both BALB/c (H-2d) and C57BL/6 (H-2b) mice, compared with Alum. Anti-A antibodies induced by Alum were mainly IgG1 type accompanied by lower levels of Mdk IgG2a and IgG2b. Quil A induced powerful and almost equivalent titers of anti-A antibodies of IgG1 and IgG2a isotypes and slightly lower levels of IgG2b. Switching adjuvants from Alum to Quil A induced higher concentrations of antibodies than injections with Alum only, however slightly lower than Quil A only. Switching both adjuvants did not switch the profile of antibody reactions generated by the initial adjuvant injected. These results suggest that switching from Alum to Quil A would be beneficial for AD individuals because anti-A antibody production was enhanced without changing the in the beginning generated and likely beneficial Th2-type humoral response. Keywords: Alzheimers disease (AD), Epitope vaccine immunization, Th1 and Th2 adjuvants 1. Intro The cause of Alzheimers disease (AD) remains unclear, greatly hindering the development of successful treatments for this devastating disease. The neuropathological features of AD include neurofibrillary tangles (NFT), deposition of -amyloid (A) in senile plaques, and neuronal loss in affected mind regions [1]. The A peptide is definitely thought to have a central part in the onset and progression of AD [2,3]. This is supported by results of studies using different transgenic mouse models of AD that express mutated forms of human being amyloid precursor protein (APP), from which A is definitely cleaved [4C6]. Such manifestation of APP induces cerebral deposition of A in the form of monomers, oligomers, protofibrills, and plaques, and mimics different aspects of AD in mice [7C9]. It is believed that build up of toxic forms of A deposits in the brain have a significant, probably central part in the onset and progression of AD. Various strategies currently proposed as therapies for AD are aimed at reducing the level of A in the brain or obstructing the assembly of the peptide into pathological forms. One potentially powerful strategy for reducing the level of A in the brain is definitely immunotherapy, in which antibodies specific to A facilitate the clearance of amyloid deposits [10C18]. The 1st human being AD vaccine consisted of fibrillar A42 formulated in QS21 adjuvant (AN-1792 trial) that induced strong Th1-type anti-A immune responses [19], actually in Th2-susceptible BALB/c mice [20]. This AN-1792 medical trial was halted due to the development of meningoencephalitis in a small proportion of the subjects [21C26], but follow up studies have shown that strong anti-A antibody reactions specific to the linear A1C8 peptide [27] in some patients reduced AD pathology and diminished the cognitive decrease associated with the disease [24,27C33]. These data along with preclinical studies shown that anti-A antibodies directed to N-terminal region of A42 are effective in clearance of amyloid plaques [16,34,35]. On the contrary, the strong autoreactive Th1-type response specific to A is definitely thought to underlie the development of meningoencephalitis observed in the AN-1792 trial [30,31,33]. It is known that Th1-type pro-inflammatory immune responses that are important for the generation of safety against viral infections and cancer will also be implicated in autoimmune disorders, whereas Th2-type anti-inflammatory reactions possess generally been shown to inhibit autoimmune disease. It is important, consequently, that future AD immunotherapy results in the clearing of A peptides by specific anti-A antibodies while limiting the Th1-type immune response [28C33]. To reduce the risk of an adverse T cell-mediated immune response to A-immunotherapy, we developed an epitope vaccine, PADRE-A1C15-MAP, and shown that immunizations with this vaccine induced high titers of anti-A antibodies, but not anti-PADRE antibodies. Formulation of our immunogen in the Th2-type adjuvant, Alum, was performed to direct the antibody response toward a Th2 phenotype in an attempt to avoid a strong Th1 humoral response, while keeping potentially beneficial anti-A antibody response [36]. Alum, however, is much less potent than the majority of Th1-type adjuvants including saponin (QS21) [19,37C40], sometimes as much as 200-collapse [41]. Therefore, we suggested that the combined use of both Th1- and Th2-type adjuvants may be more effective and safe immunotherapy for AD. In the present PD166866 study, we compared the immunogenicity of our novel prototype epitope vaccine that contains the immunodominant B cell epitope of A1C15 in tandem with the synthetic common helper T cell epitope, PADRE (PADRE-A1C15-MAP) [36] formulated in Th1-type adjuvant (Quil A) or Th2-type adjuvant (Alum). To identify an acceptable adjuvant formulation for use in long term pre-clinical and medical tests, we tested the use of different mixtures of Quil A and Alum in BALB/c and C57BL/6 mice of two.
