Progressive aggregation of protein Tau into oligomers and fibrils correlates with cognitive decline and synaptic dysfunction, leading to neurodegeneration in vulnerable brain regions in Alzheimer's disease. The unmet need of effective therapy for Alzheimer's disease, combined with problematic pharmacological approaches, led the field to explore immunotherapy, first against amyloid peptides and recently against protein Tau. Here we adapted the liposome-based amyloid vaccine that proved safe and efficacious, and incorporated a synthetic phosphorylated peptide to mimic the important phospho-epitope of protein Tau at residues pS396/pS404. We demonstrate that the liposome-based vaccine elicited, rapidly and robustly, specific antisera in wild-type mice and in Tau.P301L mice. Long-term vaccination proved to be safe, because it improved the clinical condition and reduced indices of tauopathy in the brain of the Tau.P301L mice, while no signs of neuro-inflammation or other adverse neurological effects were observed. The data corroborate the hypothesis that liposomes carrying phosphorylated peptides of protein Tau have considerable potential as safe and effective treatment against tauopathies, including Alzheimer's disease.

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Total-recoverable metals (Al, Cr, Cu, Fe, Mn, Ni, Pb and Zn) in sediments from Minho estuary salt marsh were determined to evaluate possible increase in anthropogenic contamination by metals and to evaluate the possibility of this area to be considered a pristine area in terms of metals, which can be used as a reference site for other metal-contaminated national and international estuaries/salt marshes. This study revealed that the spatial distribution of metals in the salt marsh sediments was not homogeneous and that two sampling sites (sites 5 and 7) had indications of anthropogenic contamination. However, metal levels in these salt marsh sediments were lower than those observed in the wetlands of the main Portuguese estuaries. Comparison with Portuguese and international reference values used in the evaluation of the ecological quality of sediments, indicated that the sediments can be classified as "clean sediment" and that metal levels were lower or similar (only for Cu and Ni) to the values of ERL, which are the values that define the concentrations ranges that are rarely associated to adverse biologic effects in organisms. In addition, metal levels in the sediments were in chemical forms that were not easily available to organisms, indicating that these sediments probably will not have negative influences in the organisms living in the salt marsh, although no life-form ecological safety tests have been carried out. Therefore, the Minho estuary salt marsh area can probably be considered a pristine area in terms of metals and can be used as a reference for other metal-contaminated estuaries/salt marshes.

Immunoglobulin class switching from IgM to IgG in response to peptides is generally T cell-dependent and vaccination in T cell-deficient individuals is inefficient. We show that a vaccine consisting of a dense array of peptides on liposomes induced peptidespecific IgG responses totally independent of T-cell help. Independency was confirmed in mice lacking T cells and in mice deficient for MHC class II, CD40L, and CD28. The IgG titers were high, long-lived, and comparable with titers obtained in wild-type animals, and the antibody response was associated with germinal center formation, expression of activation-induced cytidine deaminase, and affinity maturation. The T cellindependent (TI) IgG response was strictly dependent on ligation of TLR4 receptors on B cells, and concomitant TLR4 and cognate B-cell receptor stimulation was required on a single-cell level. Surprisingly, the IgG class switch was mediated by TIR-domaincontaining adapter inducing interferon-␤ (TRIF), but not by MyD88. This study demonstrates that peptides can induce TI isotype switching when antigen and TLR ligand are IntroductionMost peptide and protein antigens require T-cell help for B-cell activation and antibody production, 1 while polysaccharides and lipopolysaccharide (LPS) can stimulate antibody responses without T help. 2 In both T cell-independent (TI) and -dependent (TD) antibody responses, cognate antigens bind their B-cell receptor (BCR). TD antigens are internalized, processed, and presented in the context of MHC class II molecules to antigen-specific T-helper cells. 3 The activated T cell then facilitates B-cell responses and immunoglobulin isotype switching via costimulatory molecules, adhesive antigens, and cytokines. TI antigens typically stimulate transient IgM antibody production with little or no IgG, IgA, or IgE production. TI type 1 (TI-1) antigens are polyclonal B-cell activators such as LPS whereas TI type 2 (TI-2) antigens consist of repetitive biochemical structures, such as polysaccharides or glycoproteins. 4 Liposomes are submicron vesicles of phospholipids and allow integration of compounds within and on the lipid bilayer. Antigens can be packed on the surface to resemble TI-2 antigens; in nature, repetitive arrangement of a single protein or peptide on cells or microorganisms does not typically occur. In the present study, a peptide was palmitoylated and mixed with phospholipids and monophosphoryl lipid A (MPLA) to allow formation of liposomes with densely arranged peptides on the outer surface. The palmitoylated human ␤-amyloid (A␤, aa1-15) peptide adopts an aggregated ␤-sheet conformation on liposomes. 5 While previous reports have suggested that nonreplicating protein vaccines do not enable TI isotype switching, 6,7 the present study in mice demonstrates that switch is feasible with a correct structural assembly of antigen and adjuvant. This result could pave the way for vaccination of patients with T-cell deficiencies or elderly, or when T-cell involvement is associated with immunopathology or autoimmunity, f...