ABSTRACT
Plasma products are considered to be special medicinesderived from healthy human plasma .During 1980′s, events of transmission of human immunodeficiency virus through plasma products were frequently reported .Since then, ensuring the viral safety of plasma products has raised great concerns all over the world .So far, with decades of effort , most countries in the world have established rigorous systems with preventive measures to ensure the viral safety of plasma prod -ucts.These measures include control of source plasma , validated inactivation/removal of infectious agents , the adherence to current good manufacturing practices .Nevertheless , new infectious agents which may be threats to viral safety require continuous studies on appropriate countermeasures .
ABSTRACT
Objective To detect the activity of α1 antitrypsin(AAT) with initial velocity of enzymatic reaction in order to detect the activity of samples in the process of separating and purifying plasma protein ,chromogenic substrate assay was optimized.Methods The effect of trypsin concentration and reaction time on enzymatic reaction was acquired by the kinetic monitoring mode of the microplate reader .Initial velocity was calculated to confirm the largest concentration of trypsin which was saturated by substrate .AAT was incubated with trypsin and absorbance produced by enzymatic reaction of remaining trypsin and substrate could reflect the activity of AAT .A standard curve was established with △D fitting with the activity of AAT standard.The activity of related samples was detected and the precision and accuracy of the method were evaluated . Results Trypsin concentration was 0.0625 mg/ml.Within 20 minutes, enzymatic reaction was with initial velocity .The range of the standard curve was 200-1200 IU/ml.Correlation coefficient was more than 0.99.The activity of Cohn Ⅳ, samples of pre-processing and elution were (720.59 ±18.63), (601.84 ±19.18),and (568.09 ±24.83)IU/ml, respec-tively.The relative standard deviation was less than 10%. Sample recovery rate was 90%-110%.Conclusion The optimized chromogenic substrate assay greatly improves accuracy and precision .The method can be used for the detec-tion of AAT activity of samples in laboratories and workshops .
ABSTRACT
Objective To predict the B cell line epitopes of human cytomegalovirus glycoprotein (gB)by analyzing its structure and physicochemical properties using bioinformatics approaches .Methods Based on the sequence of the HCMV gB,the probable B cell epitopes are predicted using two online prediction programs and DNAstar software .Meanwhile,the tertiary structure of gB was constructed by homologous modeling with the assistance of SWISS -MODEL server to rule out im-possible B cell epitopes .Results and Conclusion The B cell line epitopes of gB are predicted , which provides a theoreti-cal basis for further verification of gB immunodominant epitopes and screening the source plasma with high HCMV IgG titer .
ABSTRACT
Objective To establish viral inactivation/removal techniques for blood products , and apply them to inacti-vation/removal process validation of blood products .Methods Enveloped and non-enveloped model viruses were propaga-ted.Viral inactivation/removal techniques for blood products ,including solvent/detergent (S/D) treatment, low pH incuba-tion, dry heat method, pasteurization,and nanofiltration, were established.The virus titer was evaluated using cytopathic effects ( CPE) and Spearman and Karber method .The viral inactivation/removal techniques were believed to be effective when LRV≥4.These techniques were used in viral inactivation /removal validation of blood products .Results Enveloped model viruses were inactivated through S/D treatment and the low pH incubation method .Enveloped and non-enveloped model viruses were inactivated through dry heat and pasteurization .Within a certain range of filtration capacity , PPV was removed through nanofiltration .Conclusion The established viral inactivation/removal techniques can be used in viral inactivation/removal process validation of blood products , which can improve viral safety of blood products .
ABSTRACT
Twenty five serotypes of Bluetongue virus (BTV) have been identified worldwide. Rapid and reliable methods of virus universal detection are essential for fighting against bluetongue (BT). We have therefore developed and evaluated a pair of primers which can detect various serotypes of BTV by RT-PCR. Analysis of the viral protein 7 (VP7) and the non-structural protein (NS1) gene from different serotypes of BTV by DNAstar showed that the 5' end of the NS1 gene is the most conserved region. The primer pairs (P1 and P2) were designed based on the highly conserved region of NS1. The novel primers were evaluated by detecting BTV serotypes 1, 3, 5, 8, 10, 11, 21 and 22. The specificity of the primers was estimated by comparing to gene sequences of viruses published in GenBank, and further assessed by detecting BTV serotype 1-12 and Epizootic hemorrhagic disease virus (EHDV) serotype 1-4. The sensitivity and repeatability of PCR with the novel primers were evaluated by successfully detecting the recombinant plasmid pGEM-T121 containing the diagnosed nucleotide sequence. Our results suggest that these unique primers can be used in high throughout and universal detection of the NS1 gene from various BTV serotypes.