Revealing Vision-Language Integration in the Brain with Multimodal Networks.

We use (multi)modal deep neural networks (DNNs) to probe for sites of multimodal integration in the human brain by predicting stereoencephalography (SEEG) recordings taken while human subjects watched movies. We operationalize sites of multimodal integration as regions where a multimodal vision-language model predicts recordings better than unimodal language, unimodal vision, or linearly-integrated language-vision models. Our target DNN models span different architectures (e.g., convolutional networks and transformers) and multimodal training techniques (e.g., cross-attention and contrastive learning). As a key enabling step, we first demonstrate that trained vision and language models systematically outperform their randomly initialized counterparts in their ability to predict SEEG signals. We then compare unimodal and multimodal models against one another. Because our target DNN models often have different architectures, number of parameters, and training sets (possibly obscuring those differences attributable to integration), we carry out a controlled comparison of two models (SLIP and SimCLR), which keep all of these attributes the same aside from input modality. Using this approach, we identify a sizable number of neural sites (on average 141 out of 1090 total sites or 12.94%) and brain regions where multimodal integration seems to occur. Additionally, we find that among the variants of multimodal training techniques we assess, CLIP-style training is the best suited for downstream prediction of the neural activity in these sites.

Population Transformer: Learning Population-level Representations of Intracranial Activity.

We present a self-supervised framework that learns population-level codes for intracranial neural recordings at scale, unlocking the benefits of representation learning for a key neuroscience recording modality. The Population Transformer (PopT) lowers the amount of data required for decoding experiments, while increasing accuracy, even on never-before-seen subjects and tasks. We address two key challenges in developing PopT: sparse electrode distribution and varying electrode location across patients. PopT stacks on top of pretrained representations and enhances downstream tasks by enabling learned aggregation of multiple spatially-sparse data channels. Beyond decoding, we interpret the pretrained PopT and fine-tuned models to show how it can be used to provide neuroscience insights learned from massive amounts of data. We release a pretrained PopT to enable off-the-shelf improvements in multi-channel intracranial data decoding and interpretability, and code is available at https://github.com/czlwang/PopulationTransformer.

Development and Qualification of Analytical Methods to Support Low Concentration Drug Product in-use Studies.

The emergence of highly potent therapeutics with low expected clinical doses creates a challenge for analytical characterization of simulated drug product in-use samples. The low expected protein concentration (often µg/mL) and highly charged and sub-optimal sample matrices like 0.9% saline or 5% dextrose make ensuring dose solution stability and characterizing product quality changes difficult. Health authority expectations require analysis of low concentration in-use samples to be completed with suitable assays to ensure little to no changes are occurring during drug product dose preparation and administration, thus ensuring patient safety. However, characterization of these samples for protein concentration, size variants, charge variants and potency often necessitates additional analytical method development to improve sensitivity and compatibility with in-use samples. Here we report the development and qualification of reliable in-use methods to characterize simulated in-use samples to assist during drug product development.

A multifaceted quality improvement intervention on venous thromboembolism prophylaxis compliance in hospitalized medical patients at a comprehensive cancer center.

INTRODUCTION: Previous studies suggest that quality improvement initiatives focused on hospital-acquired venous thromboembolism have a positive impact on prescribing rates of venous thromboembolism prophylaxis, especially those that incorporate computerized changes. METHODS: We conducted a quality improvement project to determine whether education and computerized prescriber order entry system changes affect venous thromboembolism prophylaxis compliance rates in hospitalized medical patients at a Comprehensive Cancer Center. Between 1 January 2021 and 31 January 2023, 37,739 non-surgical, adult patient encounters with a length of stay > 48 h were analyzed in our study. From 18 December 2021 to 8 March 2022, provider education was delivered to the three largest admitting services, and computerized prescriber order entry changes were implemented incorporating a mandatory requirement to either order venous thromboembolism prophylaxis or document a contraindication for all patients at moderate venous thromboembolism risk. RESULTS: Monthly venous thromboembolism prophylaxis compliance rates, as defined by the Centers for Medicare and Medicaid Services VTE-1 metric, increased from a mean of 74% to 93% after the interventions. This change was driven primarily by an increased utilization of mechanical venous thromboembolism prophylaxis from 37% to 53%. CONCLUSION: Our study demonstrated that a multi-faceted intervention incorporating provider education and computerized prescriber order entry system changes can significantly increase venous thromboembolism prophylaxis compliance rates in cancer patients.

A meta-analysis and systematic review of endovascular thrombectomy versus medical management for acute basilar artery occlusion.

OBJECTIVE: Acute basilar artery occlusion (BAO) is a devastating neurologic event. As endovascular thrombectomy (EVT) became more prevalent for anterior circulation strokes, investigations were conducted in the posterior circulation. Its success in improving outcomes compared to standard medical therapy (SMT) after BAO has been debated. METHODS: We conducted a systematic review and meta-analysis of all randomized controlled trials (RCTs) and observational cohort studies evaluating EVT compared to SMT in acute BAO. We queried PubMed, Embase, and Cochrane for studies. Primary outcome was good functional outcome at 90 days (modified Rankin scale (mRS) ≤ 3). We analyzed studies for risk of bias (ROB) and calculated pooled risk ratios (RRs), odds ratios (ORs), and mean differences (MDs) with 95% confidence intervals (95%CI) using the random effects model for our primary outcome and secondary positive outcomes and harms. RESULTS: We identified four RCTs (991 patients randomized) and three cohort studies (1030 patients treated in-trial) that fit inclusion criteria. Three RCTs had low ROB, one had serious ROB. One cohort study had high ROB, one had moderate ROB, and one had low ROB. EVT was statistically significantly more associated with good functional outcome than SMT in RCTs (RR=1.54, 95%CI=1.16-2.04, p = 0.003) and trended towards significance in cohort studies (RR=2.64, 95%CI=0.87-8.00, p = 0.09). Mean mRS at 90 days was lower in EVT patients in RCTs (MD=-0.65, 95%CI=-1.07--0.22, p = 0.003) though not cohort studies (MD =-0.84, 95%CI=-2.48-0.79, p = 0.31). Symptomatic intracerebral hemorrhage (sICH) was statistically significantly associated with EVT in RCTs (OR=6.36, 95%CI=2.24-18.07, p < 0.001) and statistically non-significantly in cohort studies (OR=4.51, 95CI=1.00-20.33, p = 0.05). Mortality at 90 days was statistically lower with EVT than with SMT in both RCTs (OR=0.76, 95%CI=0.65-0.88, p < 0.001) cohort studies (OR=0.36, 95%CI=0.26-0.50, p < 0.001) CONCLUSION: EVT is associated with greater rates of good functional outcomes and lower rates of death and disability despite higher rates of periprocedural sICH.

An update of the pharmacological treatment options for generalized myasthenia gravis in adults with anti-acetylcholine receptor antibodies.

PURPOSE: This review aims to provide an update on current pharmacological agents for the management of generalized myasthenia gravis (MG). SUMMARY: MG is an autoimmune disease characterized by impaired neuromuscular transmission and muscle weakness. Most patients have autoimmune antibodies to the nicotinic acetylcholine receptor, with treatments aimed at eliminating or decreasing levels of autoantibodies. Limitations of current treatments for generalized MG include limited efficacy and serious adverse effects, indicating a continued need for new treatments. Efgartigimod alfa, a biologic newly approved by the Food and Drug Administration, provides a novel treatment option for patients with chronic generalized MG. CONCLUSION: While the landscape for treatment of generalized MG has expanded over recent years, there is still an unmet need for patients for whom multiple lines of treatment have failed. The introduction of neonatal Fc receptor antagonists such as efgartigimod alfa may have an immediate impact in patients for whom standard-of-care therapy has failed.

Traumatic Atrial Septal Defect Repair via Primary Endovascular Suture Method: Case Report and Operative Technique.

We report a case of a 20-year-old male with no prior medical history who was found to have an atrial septal defect on echocardiography following a motor vehicle accident (MVA). The patient underwent primary percutaneous defect closure using the NobleStitch EL (Heartstitch, Fountain Valley, California) cardiovascular suturing system with intra-operative Doppler echocardiogram showing no residual shunt or color flow. There were no operative complications. At five months follow-up, the patient reported no symptoms from the procedure. In the case of traumatic atrial septal defect repair, the NobleStitch EL system may be utilized as an alternative to open heart surgery.

Factors associated with hardware failure after lateral thoracolumbar fusions - A ten year case series.

OBJECTIVE: Thoracolumbar lateral interbody fusions (tLLIF) are one tool in the spine surgeon's toolbox to indirectly decompress neuroforamina while also improving segmental lordosis in a biomechanically distinct manner from posterior fusions. When part of a concomitant posterior construct, hardware failure (HF), sometimes requiring revision surgery, can occur. We sought to study the relationship between tLLIF and HF. METHODS: We conducted a retrospective study on consecutive patents who underwent tLLIF at a single academic center between January 2012 and December 2021 by seven unique neurosurgeons. Patients were excluded if they had no posterior instrumentation within their construct or if they had less than six months of follow-up. Hardware failure was defined as screw breakage or rod fracture seen on postoperative imaging. RESULTS: 232 patients were identified; 6 (2.6 %) developed HF throughout a mean follow-up of 1182 days (range =748-1647 days). Adjacent segment disease was the most common pathology addressed (75 patients (32.3 %)). The amount of posterior instrumentation both in the surgery in question and in the total construct were significantly higher in the HF cohort (4.33 ± 1.52 levels, 5.83 ± 3.36 levels) versus the non-HF cohort (2.08 ± 0.296 levels, p = 0.014; 2.86 ± 0.316 levels, p = 0.003, respectively). The number of interbody devices added in the index surgery and in the entire construct were both significantly higher in the HF cohort (3.33 ± 0.666 interbody devices, 3.33 ± 0.666 devices) than in the non-HF cohort (1.88 ± 0.152 interbody devices, p = 0.002; 2.31 ± 0.158 devices, p = 0.036, respectively). Higher amounts of lateral levels of fusion approached significance for association with HF (HF: 2.67 ± 0.844 levels, no HF: 1.73 ± 1.26 levels, p = 0.076). On multivariate analysis, only the number of interbody devices added in the index surgery was predictive of HF (Odds ratio=2.3, 95 % confidence interval=1.25-4.23, p = 0.007). CONCLUSION: Greater levels of posterior fusion, and greater numbers of interbody devices in an index surgery and in a construct as a whole, were associated with higher rates of HF in our cohort of patients with tLLIF. Greater numbers of lateral segments fused in this population may also be related to HF.

Outpatient initiation of venetoclax in patients with acute myeloid leukemia.

INTRODUCTION: Venetoclax is a treatment option in patients with acute myeloid leukemia (AML) in both the front-line and relapsed/refractory settings. Initiation of therapy has been previously restricted to the inpatient setting at some institutions due to a risk of tumor lysis syndrome (TLS) and limitations in medication access efficiency given the high cost of therapy. METHODS: We assessed the safety of initiating venetoclax in the outpatient setting through a single-arm, retrospective study of adult AML patients between April 1, 2019 and June 30, 2020. RESULTS: Eighty-two patients started venetoclax during this time, with 47 (57%) patients initiated in the outpatient setting. Fifty-five percent of patients received venetoclax as first-line treatment for AML (n = 45) and 45% of patients received venetoclax for relapsed/refractory AML (n = 37). Successful initiation, defined as no hospitalizations secondary to TLS within seven days of therapy initiation, occurred in 98% of patients. The rate of TLS was 2.1% (n = 1) following venetoclax initiation. TLS symptoms were managed during hospitalization, requiring only one day of missed AML therapy. Median turnaround time for medication access was three days. Hospitalizations within seven days occurred in 17% of patients (n = 8), with the majority due to febrile neutropenia. CONCLUSIONS: The results of our study provide further evidence for the safety and feasibility of initiating venetoclax in the outpatient setting with a pharmacist-led interdisciplinary protocol.

Reciprocal perspective as a super learner improves drug-target interaction prediction (MUSDTI).

The identification of novel drug-target interactions (DTI) is critical to drug discovery and drug repurposing to address contemporary medical and public health challenges presented by emergent diseases. Historically, computational methods have framed DTI prediction as a binary classification problem (indicating whether or not a drug physically interacts with a given protein target); however, framing the problem instead as a regression-based prediction of the physiochemical binding affinity is more meaningful. With growing databases of experimentally derived drug-target interactions (e.g. Davis, Binding-DB, and Kiba), deep learning-based DTI predictors can be effectively leveraged to achieve state-of-the-art (SOTA) performance. In this work, we formulated a DTI competition as part of the coursework for a senior undergraduate machine learning course and challenged students to generate component DTI models that might surpass SOTA models and effectively combine these component models as part of a meta-model using the Reciprocal Perspective (RP) multi-view learning framework. Following 6 weeks of concerted effort, 28 student-produced component deep-learning DTI models were leveraged in this work to produce a new SOTA RP-DTI model, denoted the Meta Undergraduate Student DTI (MUSDTI) model. Through a series of experiments we demonstrate that (1) RP can considerably improve SOTA DTI prediction, (2) our new double-cold experimental design is more appropriate for emergent DTI challenges, (3) that our novel MUSDTI meta-model outperforms SOTA models, (4) that RP can improve upon individual models as an ensembling method, and finally, (5) RP can be utilized for low computation transfer learning. This work introduces a number of important revelations for the field of DTI prediction and sequence-based, pairwise prediction in general.

Paramedian Wiltse Approach for Giant Paraspinal Lumbar Schwannoma: Technical Note and Alternative Approaches.

BACKGROUND: Paraspinal lumbar schwannomas are primarily located outside of the spinal canal with minimal extension into the neural foramen. Approaching these tumors through a traditional posterior approach can be challenging given their lateral location to the spine and is likely to require extensive bony removal and potential destabilization of the spine. Alternatives approaches have been identified that may circumvent the need for extensive bony removal. OBJECTIVE: To examine the use of the paramedian Wiltse approach for giant extraspinal tumors and compare the approach with other nonposterior approaches. METHODS: We present 2 cases in which the paramedian Wiltse approach is used to effectively approach large paraspinal schwannomas and achieve complete tumor resection without destabilization of the spine. RESULTS: The paramedian Wiltse approach along with expandable retractors systems were able to achieve complete resection of the giant paraspinal schwannomas. Neural preservation was able to be achieved in one case which was facilitated by the exposure achieved through the posterior paramedian corridor that allowed for visualization of the proximal and distal ends of the tumor. CONCLUSION: The paramedian Wiltse approach is an ideal approach to target large extraspinal schwannomas for complete resection and potential neural preservation without the need for destabilization of the spine.

Regeneration of Capto Core 700 resin through high throughput and laboratory scale studies and impact on production of a SARS-CoV-2 vaccine candidate.

During the development of a SARS-CoV-2 vaccine candidate, at the height of the COVID-19 pandemic, raw materials shortages, including chromatography resins, necessitated the determination of a cleaning in place (CIP) strategy for a multimodal core-shell resin both rapidly and efficiently. Here, the deployment of high throughput (HT) techniques to screen CIP conditions for cleaning Capto Core 700 resin exposed to clarified cell culture harvest (CCCH) of a SARS-CoV-2 vaccine candidate produced in Vero adherent cell culture are described. The best performing conditions, comprised of 30% n-propanol and ≥0.75 N NaOH, were deployed in cycling experiments, completed with miniature chromatography columns, to demonstrate their effectiveness. The success of the CIP strategy was ultimately verified at the laboratory scale. Here, its impact was assessed across the entire purification process which also included an ultrafiltration/diafiltration step. It is shown that the implementation of the CIP strategy enabled the re-use of the Capto Core 700 resin for up to 10 cycles without any negative impact on the purified product. Hence, the strategic combination of HT and laboratory-scale experiments can lead rapidly to robust CIP procedures, even for a challenging to clean resin, and thus help to overcome supply shortages.

Human cardiac myosin-binding protein C phosphorylation- and mutation-dependent structural dynamics monitored by time-resolved FRET.

Cardiac myosin-binding protein C (cMyBP-C) is a thick filament-associated protein of the sarcomere and a potential therapeutic target for treating contractile dysfunction in heart failure. Mimicking the structural dynamics of phosphorylated cMyBP-C by small-molecule drug binding could lead to therapies that modulate cMyBP-C conformational states, and thereby function, to improve contractility. We have developed a human cMyBP-C biosensor capable of detecting intramolecular structural changes due to phosphorylation and mutation. Using site-directed mutagenesis and time-resolved fluorescence resonance energy transfer (TR-FRET), we substituted cysteines in cMyBP-C N-terminal domains C0 through C2 (C0-C2) for thiol-reactive fluorescent probe labeling to examine C0-C2 structure. We identified a cysteine pair that upon donor-acceptor labeling reports phosphorylation-sensitive structural changes between the C1 domain and the tri-helix bundle of the M-domain that links C1 to C2. Phosphorylation reduced FRET efficiency by ~18%, corresponding to a ~11% increase in the distance between probes and a ~30% increase in disorder between them. The magnitude and precision of phosphorylation-mediated TR-FRET changes, as quantified by the Z'-factor, demonstrate the assay's potential for structure-based high-throughput screening of compounds for cMyBP-C-targeted therapies to improve cardiac performance in heart failure. Additionally, by probing C1's spatial positioning relative to the tri-helix bundle, these findings provide new molecular insight into the structural dynamics of phosphoregulation as well as mutations in cMyBP-C. Biosensor sensitivity to disease-relevant mutations in C0-C2 was demonstrated by examination of the hypertrophic cardiomyopathy mutation R282W. The results presented here support a screening platform to identify small molecules that regulate N-terminal cMyBP-C conformational states.

Surgical and anatomic factors predict development of leptomeningeal disease in patients with melanoma brain metastases.

BACKGROUND: Leptomeningeal disease (LMD) is a devastating complication of systemic malignancy, of which there is an unclear etiology. The aim of this study is to determine if surgical or anatomic factors can predict LMD in patients with metastatic melanoma. METHODS: A retrospective chart review was performed of 1162 patients treated at single institution for melanoma brain metastases (MBM). Patients with fewer than 3 months follow-up or lacking appropriate imaging were excluded. Demographic information, surgical, and anatomic data were collected. RESULTS: Eight hundred and twenty-seven patients were included in the final review. On multivariate analysis for the entire cohort, female gender, dural-based and intraventricular metastasis, and tumor bordering CSF spaces were associated with increased risk of LMD. Surgical resection was not significant for risk of LMD. On multivariate analysis of patients who have undergone surgical resection of a metastatic tumor, dural-based and intraventricular metastasis, ventricular entry during surgery, and metastasis in the infratentorial space were associated with increased risk of LMD. On multivariate analysis of patients who did not undergo surgery, chemotherapy after initial diagnosis and metastasis bordering CSF spaces were associated with increased risk of LMD. CONCLUSION: In a single-institution cohort of MBM, we found that surgical resection alone did not result in an increased risk of LMD. Anatomical factors such as dural-based and intraventricular metastasis were significant for developing LMD, as well as entry into a CSF space during surgical resection. These data suggest a strong correlation between anatomic location and tumor cell seeding in relation to the development of LMD.

Safety comparison of minimally invasive abdomen-only esophagectomy versus minimally invasive Ivor Lewis esophagectomy: a retrospective cohort study.

BACKGROUND: We report mortality and post-operative complications from esophageal resection in the treatment of gastroesophageal adenocarcinoma or stricture, comparing a minimally invasive abdomen-only esophagectomy (MIAE) approach with a minimally invasive Ivor Lewis esophagectomy (MIILE) approach. METHODS: A single-center retrospective cohort study of patients with esophageal adenocarcinoma or stricture treated by either MIAE or MIILE was conducted. MIAE was offered for strictures less than five centimeters or cancers that were American Joint Committee on Cancer (AJCC) Stage ≤ T2 without lymphadenopathy. Patients treated with these surgical techniques were analyzed to assess pre-operative risk, intra and post-operative variables, adverse events, and overall survival. RESULTS: This study included 17 patients undergoing MIAE and 32 patients treated with MIILE. There were a fewer median number of lymph nodes resected (p < 0.001) and shorter operative duration (p < 0.001) for MIAE compared to MIILE. MIAE patients also had significantly higher Charlson Comorbidity Index scores and ACS National Surgical Quality Improvement Program (NSQIP) surgical risk values than MIILE patients (p < 0.05). There was no difference in median estimated blood loss, length of stay, pulmonary or cardiac complications between groups. There was no significant difference in 90-day survival. CONCLUSION: A minimally invasive abdomen-only approach in a specific patient population is comparable in safety to a minimally invasive Ivor Lewis approach, with associated shorter median operative duration. MIAE patients had significantly greater pre-operative comorbidities and higher calculated peri-operative risk of complication but demonstrated similar post-operative outcomes. This suggests that MIAE may be a suitable surgical approach for treating gastroesophageal adenocarcinoma or stricture in patients deemed unsuitable for MIILE.

A Multi-Factorial Observational Study on Sequential Fecal Microbiota Transplant in Patients with Medically Refractory Clostridioides difficile Infection.

Fecal microbiota transplantation (FMT) is highly effective in recurrent Clostridioides difficile infection (CDI); increasing evidence supports FMT in severe or fulminant Clostridioides difficile infection (SFCDI). However, the multifactorial mechanisms that underpin the efficacy of FMT are not fully understood. Systems biology approaches using high-throughput technologies may help with mechanistic dissection of host-microbial interactions. Here, we have undertaken a deep phenomics study on four adults receiving sequential FMT for SFCDI, in which we performed a longitudinal, integrative analysis of multiple host factors and intestinal microbiome changes. Stool samples were profiled for changes in gut microbiota and metabolites and blood samples for alterations in targeted epigenomic, metabonomic, glycomic, immune proteomic, immunophenotyping, immune functional assays, and T-cell receptor (TCR) repertoires, respectively. We characterised temporal trajectories in gut microbial and host immunometabolic data sets in three responders and one non-responder to sequential FMT. A total of 562 features were used for analysis, of which 78 features were identified, which differed between the responders and the non-responder. The observed dynamic phenotypic changes may potentially suggest immunosenescent signals in the non-responder and may help to underpin the mechanisms accompanying successful FMT, although our study is limited by a small sample size and significant heterogeneity in patient baseline characteristics. Our multi-omics integrative longitudinal analytical approach extends the knowledge regarding mechanisms of efficacy of FMT and highlights preliminary novel signatures, which should be validated in larger studies.

A Cohort Study on Prognostic Factors for Laser Interstitial Thermal Therapy Success in Newly Diagnosed Glioblastoma.

BACKGROUND: Laser interstitial thermal therapy (LITT) is a promising approach for cytoreduction of deep-seated gliomas. However, parameters contributing to treatment success remain unclear. OBJECTIVE: To identify extent of ablation (EOA) and time to chemotherapy (TTC) as predictors of improved overall and progression-free survival (OS, PFS) and suggest laser parameters to achieve optimal EOA. METHODS: Demographic, clinical, and survival data were collected retrospectively from 20 patients undergoing LITT for newly diagnosed glioblastoma (nGBM). EOA was calculated through magnetic resonance imaging-based volumetric analysis. Kaplan-Meier and multivariate Cox regression were used to examine the relationship between EOA with OS and PFS accounting for covariates (age, isocitrate dehydrogenase-1 (IDH1) mutation, O6-methylguanine-DNA methyltransferase hypermethylation). The effect of laser thermodynamic parameters (power, energy, time) on EOA was identified through linear regression. RESULTS: Median OS and PFS for the entire cohort were 36.2 and 3.5 mo respectively. Patient's with >70% EOA had significantly improved PFS compared to ≤70% EOA (5.2 vs 2.3 mo, P = .01) and trended toward improved OS (36.2 vs 11 mo, P = .07) on univariate and multivariate analysis. Total laser power was a significant predictor for increased EOA when accounting for preoperative lesion volume (P = .001). Chemotherapy within 16 d of surgery significantly predicted improved PFS compared to delaying chemotherapy (9.4 vs 3.1 mo, P = .009). CONCLUSION: Increased EOA was a predictor of improved PFS with evidence of a trend toward improved OS in LITT treatment of nGBM. A strategy favoring higher laser power during tumor ablation may achieve optimal EOA. Early transition to chemotherapy after LITT improves PFS.

Towards a RIOK2 chemical probe: cellular potency improvement of a selective 2-(acylamino)pyridine series.

RIOK2 is an understudied kinase associated with a variety of human cancers including non-small cell lung cancer and glioblastoma. No potent, selective, and cell-active chemical probe currently exists for RIOK2. Such a reagent would expedite re-search into the biological functions of RIOK2 and validate it as a therapeutic target. Herein, we describe the synthesis of naphthyl-pyridine based compounds that have improved cellular activity while maintaining selectivity for RIOK2. While our compounds do not represent RIOK2 chemical probes, they are the best available tool molecules to begin to characterize RIOK2 function in vitro.

Fc galactosylation follows consecutive reaction kinetics and enhances immunoglobulin G hexamerization for complement activation.

Fc galactosylation is a critical quality attribute for anti-tumor recombinant immunoglobulin G (IgG)-based monoclonal antibody (mAb) therapeutics with complement-dependent cytotoxicity (CDC) as the mechanism of action. Although the correlation between galactosylation and CDC has been known, the underlying structure-function relationship is unclear. Heterogeneity of the Fc N-glycosylation produced by Chinese hamster ovary (CHO) cell culture biomanufacturing process leads to variable CDC potency. Here, we derived a kinetic model of galactose transfer reaction in the Golgi apparatus and used this model to determine the correlation between differently galactosylated species from CHO cell culture process. The model was validated by a retrospective data analysis of more than 800 historical samples from small-scale and large-scale CHO cell cultures. Furthermore, using various analytical technologies, we discovered the molecular basis for Fc glycan terminal galactosylation changing the three-dimensional conformation of the Fc, which facilitates the IgG1 hexamerization, thus enhancing C1q avidity and subsequent complement activation. Our study offers insight into the formation of galactosylated species, as well as a novel three-dimensional understanding of the structure-function relationship of terminal galactose to complement activation in mAb therapeutics.