Despite of progress in various computational methods on

Despite of progress in various computational methods on evaluating the success of various MHC-peptide binding prediction, there is no consensus on a perfect method. However, in this study, ProPred and ProPred-I servers discovered a lot of HLA-A, HLA-B, HLA-C (MHC class I proteins) and HLA-DR (MHC class II) restricted epitopic fractions from full-length QD protein. ProPred or ProPred-I recognized that QD protein could bind to several different types of HLA ephrin receptor which could trigger immune response. In the next step, comparative analysis of the continuous B-cell epitope results and predicted T-cell restricted epitopes showed several T-cell epitopes derived from B-cell binding sequences from QD protein which possibly will evoke strong both humoral and cell-mediated immune responses. The two peptide sequences of QD antigen, “AYHKGNWSGYGKDGNIGIKDEDGMNCGPIAGSCTFPTTGTSKSPSPFVDLGAKDATSG” and “GPIAGSCTFPTTGTSKSPSP” possessed these properties. In this study, E. coli BL21 (DE3) strain as suitable prokaryotic expression system could express heterologous QD protein. In this study, the E. coli BL21 (DE3) strain showed significant expression after 6–8 h of induction at 37 °C. There was no toxic effect of QD protein on the E. coli BL21 cells. The poly-histidine-tag sequence efficiently helped the purification of QD by Ni2+-affinity chromatography method. Our antigen remains to be tested for the immunological efficacy.
Several regions of QD recombinant protein from P. aeruginosa were found to be efficient antigens. Almost all conserved QD antigenic patches were enriched with irregular coil and turn motif. Our predictions showed that the QD chimeric protein with several T-cell epitopes derived from B-cell epitopes could be expressed efficiently in E. coli BL21 (DE3) strain and could serve as a good subunit of vaccine candidate against P. aeruginosa.

Conflict of interest statement

Acknowledgments

Introduction
The external ventricular drain (EVD) constitutes a clinical standard for the continuous monitoring of intracranial pressure (ICP) and facilitates the drainage of cerebrospinal fluid (CSF). Indications for an EVD include primary hydrocephalus, obstructive hydrocephalus secondary to expansive processes or intracranial haemorrhage, ICP control in patients with cranioencephalic trauma and prevention of postoperative CSF fistulas[1,2]. It facilitates the treatment using intraventricular fibrinolysis (IVF) and the administration of local antibiotics[1,3]. Its indications are limited by the risk of bleeding during the insertion procedure and the risk of ventriculostomy-related infection (VRI)[1–6]. The published indication on the VRI seems to be conflicting since incidence rates vary between 0% and above 50% depending on the authors[1,2,4–10]. There are no universal criteria to establish its diagnosis; strategies focus on clinical monitoring and blood and CSF microbiological and citobiochemical results[1,2,4,6–14]. The clinical assessment of the patient and certain test results that suggest infection (leucocytosis, CSF pleocytosis, hypoglycorrhachia, etc.) lose their predictive value due to the particular characteristics of the neurocritical patient[15–17], and they can cause delay in its detection and early treatment; the lack of rentability of the cultures and the fact that waiting is needed for their results to be available are also obstacles to an early diagnosis[18,19].
The need to establish uniform criteria which are both highly sensitive and specific for the diagnosis of VRI seems necessary, and, also, to determine CSF parameters to predict its development[12]. The etiological agent most commonly involved is the coagulase-negative staphylococci[1,2,11–13,18,20], however, the detected amount of Gram-negatives is increasing. Many factors that could contribute to the development of VRI have been identified (associated craniotomy, systemic infection, depressed cranial fracture, intraventricular haemorrhage, catheter manipulation, and instillation of local treatments)[1,2,4,11,13,14,21,22], whereas some others are subjects of continuous debate (use of prophylactic antibiotics, the number of devices, corticosteroids administration, lengthy stays in critical care units, placement site of the catheter, prophylactic replacement of the catheter, duration of the derivation, etc.)[1,4,14,20–28].