Protective immunity to ricin toxin conferred by antibodies against the toxin's binding subunit (RTB)

The B subunit (RTB) of ricin toxin is a galactose-/N-acetyl galactosamine-specific lectin that promotes attachment and entry of ricin into host cells. RTB is also the archetype of the so-called R-type lectin family, whose members include haemagglutinins of botulinum neurotoxin (BoNT) progenitor toxins, as well as the binding subunits of cytolethal distending toxins. Although RTB is an appealing subunit vaccine candidate, as well as a potential target for immunotherapeutics, the degree to which RTB immunization elicits protective antibodies against ricin toxin remains unresolved. To address this issue, groups of mice were immunized with RTB and then challenged with 5×LD₅₀s of ricin administered intraperitoneally. Despite high RTB-specific serum antibody titers, groups of RTB immunized mice were only partially immune to ricin challenge. Analysis of a collection of RTB-specific B cell hybridomas suggested that only a small fraction of antibodies against RTB have demonstrable neutralizing activity. Two RTB-specific neutralizing monoclonal IgG₁ antibodies, 24B11 and SylH3, when passively administered to mice, were sufficient to protect the animals against a 5×LD₅₀ dose of ricin. Both 24B11 and SylH3 blocked ricin attachment to terminal galactose residues and prevented toxin binding to the surfaces of bone marrow-derived macrophages (BMM), suggesting that they function by steric hindrance and recognize epitopes located on RTB's carbohydrate recognition sub-domains (1α or 2γ). These data raise the possibility of using specific RTB sub-domains, rather than RTB itself, as antigens to more efficiently elicit neutralizing antibodies and protective immunity against ricin.     

Language Abilities of Russian Primary-School-Aged Children with Autism Spectrum Disorder: Evidence from Comprehensive Assessment

Journal of Autism and Developmental Disorders - The purpose of the present research was to comprehensively assess the language abilities of Russian primary-school-aged children with Autism Spectrum...     

High‐voltage electrical injury: Modified surgical technique for optimal defect closuring of extra‐large cranial defect

Electrical burns are group of traumatic injuries with a mortality rate of 3–15%. High‐voltage induced extensive electric burns are rarely seen in the cranial area, compared to upper and lower limbs, but extremely difficult for treatment, due to the limited flexibility in this area. The spectrum of therapeutic interventions in electrical burns in general, evolving initial necrectomy, decompression, and aggressive debridement with early skin coverage is usually not enough in cases of extensive cranial defects. The performance of a suitable flap combined with skin graft in donor site, and further implantation of expander is challenging in this area. We present a case of a high‐voltage induced extra‐large cranial injury in a 38‐year‐old man, treated with modified single large rotation flap and a split skin‐thickness graft technique, for optimal defect closuring with satisfied aesthetic result.