Expression and purification of recombinant human serum albumin from selectively terminable transgenic rice

Human serum albumin(HSA) is widely utilized for medical purposes and biochemical research.Transgenic rice has proved to be an attractive bioreactor for mass production of recombinant HSA(rHSA).However,transgene spread is a major environmental and food safety concern for transgenic rice expressing proteins of medical value.This study aimed to develop a selectively terminable transgenic rice line expressing HSA in rice seeds,and a simple process for recovery and purification of rHSA for economical manufacture.An HSA expression cassette was inserted into a T-DNA vector encoding an RNA interference(RNAi) cassette suppressing the CYP81A6 gene.This gene detoxifies the herbicide bentazon and is linked to the 5-enolpyruvylshikimate-3-phosphate synthase(EPSPS) cassette which confers glyphosate tolerance.ANX Sepharose Fast Flow(ANX FF) anion exchange chromatography coupled with Butyl Sepharose High Performance(Butyl HP) hydrophobic interaction chromatography was used to purify rHSA.A transgenic rice line,HSA-84,was obtained with stable expression of rHSA of up to 0.72% of the total dry weight of the dehusked rice seeds.This line also demonstrated high sensitivity to bentazon,and thus could be killed selectively by a spray of bentazon.A two-step chromatography purification scheme was established to purify the rHSA from rice seeds to a purity of 99% with a recovery of 62.4%.Results from mass spectrometry and N-terminus sequencing suggested that the purified rHSA was identical to natural plasma-derived HSA.This study provides an alternative strategy for large-scale production of HSA with a built-in transgene safety control mechanism.

A review of the risk factors associated with juvenile-onset recurrent respiratory papillomatosis:genetic,immune and clinical aspects

Background Juvenile-onset recurrent respiratory papillomatosis(JoRRP)is one of the most common benign lesions of hyperplastic respiratory epithelial tissue in children and is predominantly caused by human papillomaviruses(HPVs)6 and 11.The clinical course of the disease is variable,and some patients even develop a malignancy.The purpose of this review was to summarize the related factors affecting the disease course in patients with JoRRP.Data sources We used databases,including PubMed and Google Scholar,to search for publications on factors associated with the genetic,immune,and clinical aspects of JoRRP.The most relevant articles to the scope of this review were chosen for analysis.Results Mother-to-child transmission is the most important mode of disease transmission;other factors,such as immune condition or genetic susceptibility,may be important determinants of JoRRP occurrence.Genetically,the presence of DRBI*0301 and HFV 6/11 E6/E7 is associated with a more severe disease.Immunewise,patients have an enhanced T helper 2-like response.In addition,regulatory T cells are enriched in tumors and may become one of the effective prognostic indicators.For clinical characteristics,patients infected with HPV-11 have more aggressive disease.However,compared with HPV type,age at first onset is a more important factor related to the aggressiveness of JoRRP.Furthermore,socioeconomic status may also affect the course.Conclusions Genetic,immune,and some clinical factors have been noted to play an important role in the course of JoRRP.Exploring definite influencing factors will be an important direction of research in the future.