Because of the importance find more and immunogenicity of the M protein

in GAS infections, some vaccine models against GAS are being developed that involve different regions of this protein. A vaccine currently under clinical trials is based on the N-terminal region of the M protein and contains sequences from 26 of the most prevalent serotypes of GAS in the USA [16], [17], [18] and [19]. Additionally, an Australian group has developed a vaccine based on a C-terminal B epitope in the M protein that is conjugated to a universal T epitope and Toll-like receptor target lipoproteins [20]. We have been studying a sequence of amino acids present in the C-terminus of the M protein to develop a subunit vaccine that is able

to induce protection against different GAS strains. To SCH 900776 supplier define the vaccine epitope, we tested a large panel of approximately 900 sera and peripheral blood mononuclear cell (PBMC) samples that enabled us to identify both B and T immunodominant epitopes and then to construct a candidate vaccine composed of 55 of these amino acid residues [21]. Recently, we showed that this vaccine epitope, identified as StreptInCor (medical identity), has three-dimensional structural features that make it recognizable to any HLA class II resulting in T cell activation and differentiation into effectors and memory cells [22]. Specific antibodies raised against StreptInCor were able to recognize heterologous M1 protein in immunized isogenic mice, which suggests that our candidate vaccine has broad coverage. MHC-II transgenic mouse models have a complete deletion of murine H2 molecules [23]. These models are an important approach to study the relationship of HLA-II molecules and autoimmunity [24], [25], [26] and [27]

and therefore could be an important model to study the immune response to vaccines. Cell press In the present work, MHC class II transgenic mice carrying human HLA class II alleles were evaluated. HLA DRB1.1502 (DR2), DRB1.0401 (DR4), DQB1.0601 (DQ6) and DQB1.0302 (DQ8) transgenic mice were used to study humoral immune responses after immunization with StreptInCor. These animals were followed for 12 months to monitor the humoral immune responses and safety control. The results presented here showed high titers of specific antibodies, and no signs of tissue damage or autoimmune disorders were observed, indicating that the StreptInCor could be an immunogenic and safe vaccine. The vaccine epitope consists of 55 amino acid residues as follows: KGLRRDLDASREAKKQLEAEQQKLEEQNKISEASRKGLRRDLDASREAKKQVEK, as previously described [21] (patents INPI 0501290/0604997-4, PCT-BR07/000184). Specific pathogen-free, 6- to 8-week-old HLA-class II DRB1*1502 (DR2), DRB1*0401 (DR4), DQB1*0601(DQ6) and DQB1*0302 (DQ8) transgenic mice were used in this study [24], [25] and [28]. All transgenic mice were kindly provided by Dr. Chella S.