Potential Application Of A Novel Immunotherapeutic TG1050 From HBV Patients In China

Background&Aims:Chronic Hepatitis B(CHB)infection is one of the major public health challenges in the world.Because of strong interplay between specific T cell immunity and elimination of HBV,efforts at developing novel immunotherapeutic are gaining attention.Encoding a unique and large fusion protein derived from genotype D sequence,TG1050,an adenovirus 5-based immunotherapy has shown efficacy in animal study.In order to support the clinical development of TG1050 in China,specific immunity to the vector and fusion antigens of TG1050 were assessed in Chinese patients chronically infected by genotype B or C virus.In parallel,a novel biomarker was explored to reveal the specific immune responses in CHB patients.Subjects and Methods:Part I:Ad5-specific neutralizing antibody titers were measured using an adapted luciferase-based virus neutralization assay in 200 plasma samples from healthy donors and 204 serum samples from CHB patients.Part II:136 subjects were included and they were divided into three groups(CHB na?ve patients,HBV spontaneously resolved patients,and CHB patients with complete response,CR).HBV specific T-cell responses to pools of HBV core or polymerase peptides(Pol1,Pol2,Pol3)were evaluated using an ELISPOT assay and an intracellular cytokine staining assay.Part III:The plasma s CD163 level were evaluated by ELISA assay and CD163 expression on monocytes were determinated by flow cytometry in 167 healthy donors,HBV na?ve patients,HBV spontaneously resolved patients and CR patients.Furthermore,the relationship between s CD163/CD163 and HBV specific immune responses was addressed.Results:Part I:No significant differences of Ad5 neutralizing antibody was observed between healthy subjects and CHB patients(63.5%vs 72.06%,p=0.066).By comparison with similar studies,a high percentage of subjects harbored no detectable antibodies(32.2%)while proportion of subjects displaying very high antibody titers was low(4%).Neither demographic factors(age,gender)nor ALT or HBV DNA titers affected detection of Ad5-specific neutralizing antibody.Part II:Following HBV genotype D peptides pools recall,PBMCs from 136 HBV patients lead to detection of HBV core or polymerase 1-3 multi-specific CD4+and CD8+T cell(CHB na?ve patients:21.3%,41.1%,31.1%,16.7%;HBV spontaneously resolved patients:31.3%,25.0%,29.4%,5.9%;CR:44.8%,51.7%,37.9%,Pol3 28.6%).The percentage of HBV core specific immune responders(44.8%)were significant higher in CHB patients with CR than CHB na?ve patients or HBV spontaneously resolved patients.For IFN?response in CHB na?ve patients,Pol1 peptides pool was most immunogenic,inducing a highest percentage of responders(41.1%)and intensity.Clinical variables showed no influence in HBV specific immune responses expect for platelet count;higher numbers of platelet were rather observed in responders after Pol1 peptides pool recall.This observation is intriguing and will need to be confirmed further.Part III:The circulating s CD163 levels were highest in CHB na?ve patients(1108.4±721.41ng/m L),followed in CHB patients with CR(531.53±314.29ng/m L),healthy subjects(374.3±227.90ng/m L),and HBV spontaneously resolved patients(242.8±111.12ng/m L).In CHB na?ve patients,plasma s CD163 levels were associated with liver inflammation parameters such as ALT,AST,bilirubin,and also with platelet counts.Flow cytometry analysis revealed that the expression of CD14~+CD16~-CD163~+and CD14~+CD16~+CD163~+monocytes was significantly higher in responders to HBV pol1 peptides pool than non-responders in CHB na?ve patients;while in CHB patients with CR,their expression on CD14~+CD16~-monocytes was higher in responders to Core peptide pool than non-responders.Conclusion:The sero-prevalence and titer of Ad5 neutralizing antibody were not affected by HBV infection status.TG1050 encoding HBV genotype D derived peptides could raise a broad and functional T cell responses in PBMCs from genotype B or C infected Chinese patients.All these elements support the potential application of adenovirus 5-based novel immunotherapeutic TG1050 in China.Plasma s CD163 levels were considerable reduced in CHB patients who have a partial restoration of HBV specific T cells responses,and were associated with liver inflammations parameters.The expression of CD163 on monocyte subsets was correlated with specific immune responses to recall HBV peptides.Altogether,our data illustrated that the s CD163 and CD163 may serve as useful biomarker,reflecting HBV inflammation degree as well as HBV specific immunity.