Dynamic Covalent Dextran Hydrogels as Injectable, Self-adjuvating Peptide Vaccine Depots

Dextran-based hydrogels are promising therapeutic materials for drug delivery, tissue regeneration devices, and cell therapy vectors, due to their high biocompatibility, along with their ability to protect and release active therapeutic agents. This report describes the synthesis, characterization and application of a new dynamic covalent dextran hydrogel as an injectable depot for peptide vaccines. Dynamic covalent crosslinks based on double Michael addition of thiols to alkynones impart the dextran hydrogel with shear-thinning and self-healing capabilities, enabling hydrogel injection. These injectable, non-toxic hydrogels show adjuvant potential and have predictable sub-millimolar loading and release of the peptide antigen SIINFEKL, which after its release is able to activate T-cells, demonstrating that the hydrogels deliver peptides without modifying their immunogenicity. This work demonstrates the potential of dynamic covalent dextran hydrogels as a sustained-release material for delivery of peptide vaccines.

Characterization and evaluation of a recombinant multiepitope peptide antigen MAG in the serological diagnosis of Toxoplasma gondii infection in pigs

Background Toxoplasmosis caused by Toxoplasma gondii is a serious disease threatening human and animal health. People can be infected with T. gondii by ingesting raw pork contaminated with cysts or oocysts. Serological test is a sensitive and specific method usually used for large-scale diagnosis of T. gondii infection in humans and animals (such as pigs). Commercial pig Toxoplasma antibody ELISA diagnostic kits are expensive, which limits their use; moreover, the wide antigen composition used in these diagnostic kits is still unclear and difficult to standardize. The multiepitope peptide antigen is a novel diagnostic marker, and it has potential to be developed into more accurate and inexpensive diagnostic kits. Methods The synthetic multiepitope antigen (MAG) cDNA encoding a protein with epitopes from five T. gondii-dominant antigens (SAG1, GRA1, ROP2, GRA4, and MIC3) was designed, synthesized, and expressed in Escherichia coli BL21 (DE3) strain. The recombinant protein was detected through western blot with pig anti-T. gondii-positive and -negative serum, and then IgG enzyme-linked immunosorbent assay (ELISA) named MAG-ELISA was designed. The MAG-ELISA was evaluated in terms of specificity, sensitivity, and stability. The MAG-ELISA was also compared with a commercial PrioCHECK®Toxoplasma Ab porcine ELISA (PrioCHECK ELISA). Finally, the trend of pig anti-T. gondii IgG levels after artificial infection with RH tachyzoites was evaluated using MAG-ELISA and two other ELISA methods (rMIC3-ELISA and PrioCHECK ELISA). Results MAG antigen could be specifically recognized by pig anti-T. gondii-positive but not -negative serum. MAG-ELISA showed high diagnostic performance in terms of specificity (88.6%) and sensitivity (79.1%). MAG-ELISA could be used for detecting anti-T. gondii IgG in the early stage of T. gondii infection in pigs (at least 7 days after artificial infection). Conclusions Our results suggest that MAG antigen can be applied to specifically recognize anti-T. gondii IgG in pig, and MAG-ELISA has the potential for large-scale screening tests of T. gondii infection in pig farms and intensive industries. Graphical abstract

Characterization and Evaluation of a Recombinant Multiepitope Peptide Antigen MAG in the Serological Diagnosis of Toxoplasma Gondii Infection in Pigs

Background Toxoplasmosis caused by toxoplasma gondii (T. gondii) is a serious disease threatening human and animal health. People could be infected with T. gondii by ingesting raw pig meat contaminated with cysts or oocysts. Serological test is a sensitive and specific method usually used for large-scale diagnosis of T. gondii infection in humans and animals (such as pigs). Since commercial pig toxoplasma antibody ELISA diagnostic kits are too expensive, it is difficult to use them widely, moreover, the native antigen composition used in these diagnostic kits is still unclear and difficult to standardize. The multiepitope peptide antigen is novel diagnostic marker, and it has the potential to be developed into more accurate and inexpensive diagnostic kits. Methods The synthetic multiepitope antigen (MAG) gene encoding a protein with epitopes from 5 T. gondii dominant antigen (SAG1, GRA1, ROP2, GRA4, and MIC3) was designed, synthesized, and expressed in Escherichia coli BL21 (DE3) strain. The recombinant protein was detected through western blot with pig anti-T. gondii positive and negative serum, then IgG enzyme-linked immunosorbent assay (ELISA) named MAG-ELISA was designed. The MAG-ELISA was evaluated in terms of specificity, sensitivity, and stability. The MAG-ELISA was also compared with a commercial PrioCHECK® Toxoplasma Ab porcine ELISA (PrioCHECK ELISA). Finally, the trend of pig anti-T. gondii IgG level after artificially infection with RH tachyzoites was evaluated through MAG-ELISA and two other ELISA methods (rMIC3-ELISA and PrioCHECK ELISA). Results MAG antigen could be specifically recognized by pig anti-T. gondii positive but not negative serum. MAG-ELISA possessed a high diagnostic performance in terms of specificity and sensitivity. The overall coincidence rate between MAG-ELISA and a commercial PrioCHECK Toxoplasma antibody ELISA was 78.47%. MAG-ELISA could be used for detecting anti-T. gondii IgG in the early stage of T. gondii infection in pigs (at least 7 days after artificial infection). Conclusions Our results suggest that MAG antigen could be applied to specifically recognize anti-T. gondii IgG in pig, and MAG-ELISA has the potential for large-scale diagnosis of T. gondii infection in pig farms and intensive industries.

A mimotope attached to an ITIM–SHP-1 interaction inhibitory peptide boosts immune response and efficacy

Conformationally-constrained antigen is more immunogenic and attenuation of inhibitory Fc receptor by ITIM mimicking peptide enhance antibody production to a defined peptide antigen.

Gambaran Uji Cukit Kulit Pada Mahasiswa Fakultas Kedokteran Universitas Muhammadiyah Yogyakarta dengan Gejala Rhinitis Alergi

Latar Belakang: Rhinitis alergi (RA) adalah penyakit saluran napas atas yang disebabkan oleh reaksi inflamasi yang diperantarai IgE setelah adanya pajanan alergen. Uji cukit kulit merupakan tes standar yang digunakan dalam menegakkan diagnosis RA. Uji cukit kulit memberikan informasi keberadaan IgE spesifik terhadap protein dan peptide antigen atau yang dikenal dengan alergen.Tujuan: Mengetahui gambaran hasil pemeriksaan uji cukit kulit pada mahasiswa fakultas kedokteran Universitas Muhammadiyah Yogyakarta dengan gejala rhinitis alergi.Metode penelitian: Deskriptif melalui metode potong lintang.Hasil: Sebanyak 28 orang dengan gejala rhinitis alergi telah menjalani pemeriksaan uji cukit kulit. dengan jenis kelamin perempuan sebanyak 21 orang, laki-laki sebanyak 7 orang. Jenis alergen terbanyak yang didapatkan adalah tungau debu rumah dan kacang tanah sebanyak 14 orang (50%). Persentase alergen lain pada hasil uji cukit kulit pada penelitian ini adalah bulu anjing didapatkan pada 13 orang (46,43%), putih telur 13 orang (46,43%), udang 12 orang (42,86%), daging sapi 12 orang (42,86%), kuning telur 12 orang (42,86%), kedelai 12 orang (42,86%), coklat 12 orang (42,86%), kopi 12 orang (42,86%), nanas 12 orang (42,86%), kepiting 11 orang (39,29%), cumi 11 orang (39,29%), ikan air tawar 11 orang (39,29%), teh 11 orang (39,29%), kerang 10 orang (35,71%), tongkol 10 orang (35,71%), daging ayam 9 orang (32,14%), serta susu 8 orang (28,57%).Kata kunci: rhinitis alergi, alergen, uji cukit kulit