Clonal multi-omics reveals Bcor as a negative regulator of emergency dendritic cell development.

Despite advances in single-cell multi-omics, a single stem or progenitor cell can only be tested once. We developed clonal multi-omics, in which daughters of a clone act as surrogates of the founder, thereby allowing multiple independent assays per clone. With SIS-seq, clonal siblings in parallel "sister" assays are examined either for gene expression by RNA sequencing (RNA-seq) or for fate in culture. We identified, and then validated using CRISPR, genes that controlled fate bias for different dendritic cell (DC) subtypes. This included Bcor as a suppressor of plasmacytoid DC (pDC) and conventional DC type 2 (cDC2) numbers during Flt3 ligand-mediated emergency DC development. We then developed SIS-skew to examine development of wild-type and Bcor-deficient siblings of the same clone in parallel. We found Bcor restricted clonal expansion, especially for cDC2s, and suppressed clonal fate potential, especially for pDCs. Therefore, SIS-seq and SIS-skew can reveal the molecular and cellular mechanisms governing clonal fate.

Minipool testing for SARS-CoV-2 RNA in United States blood donors.

BACKGROUND: SARS-CoV-2 RNA prevalence in blood donors from large geographic areas of high community transmission is limited. We tested residual donor plasma minipools (MPs) to determine SARS-CoV-2 RNAemia prevalence in six United States areas. STUDY DESIGN/METHODS: Blood donations collected from 7 March 2020 to 25 September 2020 were tested for SARS-CoV-2 RNA (vRNA) in MP of 6 or 16 donations using the Grifols Procleix SARS-CoV-2 research-use only (RUO) transcription-mediated amplification (TMA) assay. Reactive results were confirmed using an alternate target region TMA assay. Reactive MPs were tested by TMA after serial dilution to estimate viral load. Testing for anti-SARS-CoV-2 antibodies and infectivity was performed. RESULTS: A total of 17,995 MPs corresponding to approximately 258,000 donations were tested for vRNA. Three confirmed reactive MP16 were identified. The estimated prevalence of vRNA reactive donations was 1.16/100,000 (95% CI 0.40, 3.42). The vRNA-reactive samples were non-reactive for antibody, and the estimated viral loads of the (presumed single) positive donations within each MP ranged from <1000 to <4000 copies/ml. When tested, no infectivity was observed in inoculated permissive cell cultures. DISCUSSION: Blood donation MP-nucleic acid testing (NAT) indicated that SARS-CoV-2 RNAemia is infrequent and, when detected, the vRNA was at low concentrations. Only one RNA-reactive MP could be tested for infectivity for operational reasons and was not infectious in cell culture. These findings support current recommendations from international and national regulatory agencies to not screen donors by NAT.

NAT positivity in seronegative voluntary blood donors from western India.

BACKGROUND AND OBJECTIVES: Prevalence and composition of Hepatitis B, Hepatitis C and HIV-1, NAT positive but seronegative voluntary blood donors from western part of India is yet to be documented. MATERIAL AND METHODS: Over last 2 1/2 years all the seronegative voluntary blood donors were tested using 10 minipools on a semiautomated NAT testing platform. The positively tested donors were followed up for at least five months for development of seropositivity. RESULTS: 79532 seronegative donations were tested by 10 minipool (MP) NAT leading to 51 positive sample (44 Hep B, 5 HIV 1 and Hep C positive). All the HIV and Hep C NAT positive donors eventually developed seropositivity and out of 44 Hep B NAT positive donors, 31 developed seropositivity within six months of follow up, following counseling of the donors. This data translate into NAT yield of 1:1559 donors for all virus taken together. NAT yield for Hep B 1:1807 donors were much higher than HIV 1 in 1:15906 and HCV yield of 1:39761. Semiautomated minipool NAT testing system was found to be cost effective way for improving blood safety. INTERPRETATION AND CONCLUSION: Seronegative NAT yield in voluntary blood donors are quiet high in western part of India and in line with rest of the country is mainly due to Hepatitis B infection. Implementation of strict donor screening, Hep B vaccination of the population and sample mutation of NAT testing should be under taken on war footing.

Blood Donation Screening of Transfusion-Transmissible Viral Infection Using Two Different Nucleic Acid Testing (NAT) Platforms: A Single Tertiary Care Oncology Centre Experience.

Nucleic acid testing (NAT) is used to screen transfusiontransmittable infections (TTIs) in donated blood samples and provide an additional layer of blood safety. In this study, we describe our experience in screening viral TTIs using two formats of NAT: cobas® MPX2 polymerase chain reaction- based minipool NAT (PCR MP-NAT) and Procleix Utrio Plus transcription-mediated amplificationbased individual donor-NAT (TMA ID-NAT). Data routinely collected as a part of blood bank operations were retrospectively analysed over a period of 70 months for TTIs. Blood samples were initially screened for HIV, HBV, HCV, syphillis by chemiluminescence and malaria by Rapid card test. In addition to serological testing, all samples were further screened by TMA-based ID-NAT (ProcleixUltrio Plus Assay) during Jan 2015-Dec 2016, and by PCR-based MP-NAT (Cobas® TaqScreen MPX2) during Jan 2017-Oct 2020. RESULTS: A total of 48,151 donations were processed over 70 months, of which 16,212 donations were screened by ProcleixUtrio Plus TMA ID-NAT and 31,939 donations by cobas® MPX2 PCR MP-NAT. Replacement donors and male donors outnumbered voluntary donors and female donors respectively. The overall NAT yield rate of MP-NAT was 1:2281 compared to 1:3242 with ID-NAT, during the respective time period. ID-NAT detected 5 HBV infections missed by serology, whereas MP-NAT detected 13 HBV infections and 1 HCV infection missed by serology. The proportion of donations that were both seroreactive and NAT reactive was higher with MP-NAT (59.8%) compared to ID-NAT (34.6%). Cobas® MPX2MP-NAT had higher overall NAT yield rate compared to ProcleixUtrio Plus ID-NAT and confirmed a higher proportion of seroreactive donations. Due to the ease of operation, simple algorithm, cobas® MPX2 PCR based MP-NAT can be an effective solution for blood screening in India.

Quality comparability assessment of a SARS-CoV-2-neutralizing antibody across transient, mini-pool-derived and single-clone CHO cells.

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has triggered a serious public health crisis worldwide, and considering the novelty of the disease, preventative and therapeutic measures alike are urgently needed. To accelerate such efforts, the development of JS016, a neutralizing monoclonal antibody directed against the SARS-CoV-2 spike protein, was expedited from a typical 12- to 18-month period to a 4-month period. During this process, transient Chinese hamster ovary cell lines are used to support preclinical, investigational new drug-enabling toxicology research, and early Chemistry, Manufacturing and Controls development; mini-pool materials to supply Phase 1 clinical trials; and a single-clone working cell bank for late-stage and pivotal clinical trials were successively adopted. Moreover, key process performance and product quality investigations using a series of orthogonal and state-of-the-art techniques were conducted to demonstrate the comparability of products manufactured using these three processes, and the results indicated that, despite observed variations in process performance, the primary and high-order structures, purity and impurity profiles, biological and immunological functions, and degradation behaviors under stress conditions were largely comparable. The study suggests that, in particular situations, this strategy can be adopted to accelerate the development of therapeutic biopharmaceuticals and their access to patients.

Significance of Adopting Nucleic Acid Amplification Technique for Blood Donor Screening in a Resource Limited Setting: A Study from a Single Centre in South India.

Nucleic acid Amplification testing (NAT) has helped improve blood safety and detect window period and Occult Hepatitis B infections (OBI) This study was aimed at determining the following in blood donors: 1. seroprevalence of HIV, HBV & HCV, malarial parasite and Syphlis 2. NAT and seroyield for HIV, HBV and HCV 3. viral load in NAT yield donations 4. Pattern of HBV serological markers in HBV NAT yield donations 80,809 blood donations were screened over an 8 year period (2012-2019) for antiHIV I and II, HBsAg, antiHCV antibodies, malarial parasite and VDRL. Seronegative samples were tested by NAT using a multiplex PCR in a pool of six. NAT yield samples were tested for viral load and HBV serological markers. Seropositive samples were tested for NAT and checked for seroyield. SPSS windows version 24.0 was used for statistical analysis. 1.07% of blood donors were found to be seropositive with 0.08%, 0.86%, 0.09%, 0.03% and 0 for anti HIV I and II, HBsAg, antiHCV, VDRL and Malarial parasite respectively. Out of 79,938 seronegative samples, 20 samples (0.025%) were NAT positive for Hepatitis B with a NAT yield OF 1:3997. Out of the 20 NAT positive samples, 17 were OBI and three were window period infections. 14 NAT yield samples subjected to a HBV viral load assay showed a range of < 6-146 IU/ml. Minipool NAT in pools of six is able to indentify both OBI and window period infections. NAT could significantly improve the blood safety in a resource limited setting like India.

Adaptation of a Public-Private Partnership Model for the Implementation of Minipool Nucleic Acid Testing for Screening Routine Blood Donations and Assay Evaluation.

Background Nucleic acid amplification testing (NAT) for the screening of blood donations is known to improve blood safety. The decision to initiate NAT requires careful deliberation of infrastructure, skilled manpower, and financial resources. This report outlines the initiative of the Government of Odisha to implement NAT screening in government blood banks in the state of Odisha, India, through public-private partnership (PPP) and evaluates the incremental yield of minipool NAT screening over serology testing of blood donations. Methods Blood donations collected between June 2016 and September 2018 were initially screened for HBV (HBsAg), HCV (anti-HCV), and HIV (anti-HIV-1 and HIV-2) by ELISA, and syphilis and malaria. Sero-nonreactive donations were further screened in pools of six by Roche cobas TaqScreen MPX test version 2.0 (MPX2) NAT. Results On screening 3,39,472 blood donations, 1.34% seroreactive donations were detected. In all, 847 NAT-reactive donations (0.26%): 693 HBV, 58 HCV, and 96 HIV were detected. The NAT yields were 1:386 overall, 1:472 for HBV, 1:5642 for HCV, and 1:3409 for HIV. Conclusion NAT testing using the highly sensitive MPX2 assay leads to incremental detection of TTIs over serology. Implementation of NAT along with serological testing in blood centers all over India will be an important step towards providing safe blood. Our study not only highlights the benefits of minipool NAT testing but also presents a scalable PPP model that can serve as a template for application across other states.

High Frequency Occult Hepatitis B Virus Infection Detected in Non-Resolved Donations Suggests the Requirement of Anti-HBc Test in Blood Donors in Southern China.

Background: Most Chinese Blood Centers adopted mini pool (MP) nucleic acid testing (NAT) for HBV screening due to high cost of Individual donation (ID) NAT, and different proportions of MP-reactive but ID-non-reactive donations (MP+/ID-, defined as non-resolved donations) have been observed during daily donor screening process. Some of these non-resolved donations are occult HBV infections (OBIs), which pose potential risk of HBV transmission if they are not deferred. This study is aimed to further analyze these non-resolved donations. Methods: The non-resolved plasma samples were further analyzed by serological tests and various HBV DNA amplification assays including quantitative PCR (qPCR) and nested PCR amplifying the basic core and pre-core promoter regions (BCP/PC; 295 base pairs) and HBsAg (S) region (496 base pairs). Molecular characterizations of HBV DNA+ non-resolved samples were determined by sequencing analysis. Results: Of 17,226 MPs from 103,356 seronegative blood donations, 98 MPs were detected reactive for HBV. Fifty-six out of these 98 (57.1%) reactive MPs were resolved as HBV DNA+, but the remaining 42 pools (42.9%, 252 donations) were left non-resolved with a high rate (53.2%) of anti-HBc+. Surprisingly, among 42 non-resolved MPs, 17 contained one donation identified as OBIs by alternative NAT assays. Sequence analysis on HBV DNAs extracted from these OBI donations showed some key mutations in the S region that may lead to failure in HBsAg detection and vaccine escape. Conclusion: A total of 53.2% of the non-resolved donations were anti-HBc+, and OBIs were identified in 40.5% of these non-resolved pools. Therefore, non-resolved donations with anti-HBc+ might pose potential risk for HBV transmission. Our present analysis indicates that anti-HBc testing in non-resolved donations should be used to identify OBIs in order to further increase blood safety in China.

Comparative study of therapeutic antibody candidates derived from mini-pool and clonal cell lines.

The long journey of developing a drug from initial discovery target identification to regulatory approval often leaves many patients with missed window of opportunities. Both regulatory agencies and biopharmaceutical industry continue to develop creative approaches to shorten the time of new drug development in order to deliver life-saving medicine to patients. Generally, drug substance materials to support the toxicology and early phase clinical study can only be manufactured after creating the final Master Cell Bank (MCB) of the clonally derived cell line, which normally takes 1-2 years. With recent advances in cell line development, cell culture process and analytical technologies, generating more homogeneous bulk/mini-pool population with higher productivity and acceptable quality attributes has become a norm, thereby making it possible to shorten the timeline to initiate First in Human (FIH) trial by using bulk/mini-pool generated materials to support toxicology and FIH studies. In this study, two monoclonal antibodies of different subclasses (IgG1 and IgG4) were expressed from the mini-pool cells as well as clonally derived cell lines generated from the same mini-pool. Cell growth, productivity, and product quality were compared between the materials generated from the mini-pool and clonally derived cell line. The results demonstrate the similarity of the antibody products generated from mini-pool cells and clonally derived cell lines from the same mini-pool, and strongly support the concept and feasibility of using antibody materials produced from mini-pool cultures for toxicology and FIH studies. The strategy to potentially shorten the FIH timeline is discussed. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:1456-1462, 2017.

Half a decade of mini-pool nucleic acid testing: Cost-effective way for improving blood safety in India.

BACKGROUND AND OBJECTIVES: It is well established that Nucleic acid testing (NAT) reduces window phase of transfusion transmissible infections (TTI) and helps improve blood safety. NAT testing can be done individually or in pools. The objectives of this study were to determine the utility, feasibility and cost effectiveness of an in-house minipool-NAT(MP-NAT). MATERIALS AND METHODS: Blood donors were screened by history, tested by ELISA and sero-negative samples were subjected to an in-house NAT by using reverse transcriptase-polymerase chain reaction (RT-PCR). Testing was done in mini-pools of size eight (8). Positive pools were repeated with individual samples. RESULTS: During the study period of Oct 2005-Sept 2010 (5 years) all blood donors (n=53729) were screened by ELISA. Of which 469 (0.87%) were positive for HIV-1, HBV or HCV. Sero-negative samples (n=53260) were screened by in-house MP-NAT. HIV-NAT yield was 1/53260 (n=1) and HBV NAT yield (n=2) was 1/26630. CONCLUSION: NAT yield was lower than other India studies possibly due to the lower sero-reactivity amongst our donors. Nevertheless it intercepted 9 lives including the components prepared. The in-house assay met our objective of improving blood safety at nominal cost and showed that it is feasible to set up small molecular biology units in medium-large sized blood banks and deliver blood within 24-48 hours. The utility of NAT (NAT yield) will vary based on the donor population, the type of serological test used, the nature of kit employed and the sensitivity of NAT test used. The limitations of our in-house MP-NAT consisted of stringent sample preparation requirements, with labor and time involved. The benefits of our MP-NAT were that it acted as a second level of check for ELISA tests, was relatively inexpensive compared to ID-NAT and did not need sophisticated equipment.