Organoid modeling of lung-resident immune responses to SARS-CoV-2 infection (preprint)

Tissue-resident immunity underlies essential host defenses against pathogens, but analysis in humans has lacked in vitro model systems where epithelial infection and accompanying resident immune cell responses can be observed en bloc. Indeed, human primary epithelial organoid cultures typically omit immune cells, and human tissue resident-memory lymphocytes are conventionally assayed without an epithelial infection component, for instance from peripheral blood, or after extraction from organs. Further, the study of resident immunity in animals can be complicated by interchange between tissue and peripheral immune compartments. To study human tissue-resident infectious immune responses in isolation from secondary lymphoid organs, we generated adult human lung three-dimensional air-liquid interface (ALI) lung organoids from intact tissue fragments that co-preserve epithelial and stromal architecture alongside endogenous lung-resident immune subsets. These included CD69+CD103+ tissue-resident and CCR7- and/or CD45RA- TRM, B, NK and myeloid cells, with conservation of T cell receptor repertoires, all corresponding to matched fresh tissue. SARS-CoV-2 vigorously infected organoid lung epithelium, alongside secondary induction of innate cytokine production that was inhibited by antiviral agents. Notably, SARS-CoV-2-infected organoids manifested adaptive virus-specific T cell activation that was specific for seropositive and/or previously infected donor individuals. This holistic non-reconstitutive organoid system demonstrates the sufficiency of lung to autonomously mount adaptive T cell memory responses without a peripheral lymphoid component, and represents an enabling method for the study of human tissue-resident immunity.

Disease diagnostics using machine learning of immune receptors (preprint)

ABSTRACT Clinical diagnoses rely on a wide variety of laboratory tests and imaging studies, interpreted alongside physical examination and documentation of symptoms and patient history. However, the tools of diagnosis make little use of the immune system’s internal record of specific disease exposures encoded by the antigen-specific receptors of memory B cells and T cells. We have combined extensive receptor sequence datasets with three different machine learning representations of the contents of immune repertoires to develop an interpretive framework, MAchine Learning for Immunological Diagnosis (Mal-ID) , that screens for multiple illnesses simultaneously. This approach can already reliably distinguish a wide range of disease states, including specific acute or chronic infections, and autoimmune or immunodeficiency disorders, and could contribute to identifying new infectious diseases as they emerge. Importantly, many features of the model of immune receptor sequences are human-interpretable. They independently recapitulate known biology of the responses to infection by SARS-CoV-2 or HIV, and reveal common features of autoreactive immune receptor repertoires, indicating that machine learning on immune repertoires can yield new immunological knowledge.

Long Term Accuracy of SARS-CoV-2 Interferon-γ Release Assay and its Application in Household Investigation (preprint)

BackgroundAn immunodiagnostic assay that sensitively detects a cell-mediated immune response to SARS-CoV-2 is needed for epidemiological investigation and for clinical assessment of T cell-mediated immune response to vaccines, particularly in the context of emerging variants that might escape antibody responses. MethodsThe performance of a whole blood interferon-gamma (IFN-{gamma}) release assay (IGRA) for the detection of SARS-CoV-2 antigen-specific CD4 and CD8 T cells was evaluated in COVID-19 convalescents tested serially up to 10 months post-infection and in healthy blood donors. SARS-CoV-2 IGRA was applied in contacts of households with index cases. Freshly collected blood in the lithium heparin tube was left unstimulated, stimulated with a SARS-CoV-2 peptide pool, and stimulated with mitogen. ResultsThe overall sensitivity and specificity of IGRA were 84.5% (153/181; 95% confidence interval [CI] 79.0-89.0) and 86.6% (123/142; 95% CI;80.0-91.2), respectively. The sensitivity declined from 100% (16/16; 95% CI 80.6-100) at 0.5-month post-infection to 79.5% (31/39; 95% CI 64.4-89.2) at 10 months post-infection (P<0.01). The IFN-{gamma} response remained relatively robust at 10 months post-infection (3.8 vs. 1.3 IU/mL, respectively). In 14 households, IGRA showed a positivity rate of 100% (12/12) and 65.2% (15/23), and IgG of 50.0% (6/12) and 43.5% (10/23) in index cases and contacts, respectively, exhibiting a difference of +50% (95% CI +25.4-+74.6) and +21.7% (95% CI, +9.23-+42.3), respectively. Either IGRA or IgG was positive in 100% (12/12) of index cases and 73.9% (17/23) of contacts. ConclusionsThe SARS-CoV-2 IGRA is a useful clinical diagnostic tool for assessing cell-mediated immune response to SARS-CoV-2. Key pointsSARS-CoV-2 immunodiagnostics are needed to identify infected individuals in order to understand the transmission dynamics of emerging variants and to assess vaccine response. Interferon-gamma release assay maintains sensitivity 10 months post-infection in convalescents and detects more household contacts than IgG.

Direct Comparison of Antibody Responses to Four SARS-CoV-2 Vaccines in Mongolia (preprint)

Different vaccines for SARS-CoV-2 are approved in various countries, but few direct comparisons of the antibody responses they stimulate have been reported. We collected plasma specimens in July 2021 from 196 Mongolian participants fully vaccinated with one of four Covid vaccines: Pfizer/BioNTech, AstraZeneca, Sputnik V and Sinopharm. Functional antibody testing with a panel of nine SARS-CoV-2 viral variant RBD proteins reveal marked differences in the vaccine responses, with low antibody levels and RBD-ACE2 blocking activity stimulated by the Sinopharm and Sputnik V vaccines in comparison to the AstraZeneca or Pfizer/BioNTech vaccines. The Alpha variant caused 97% of infections in Mongolia in June and early July 2021. Individuals who recover from SARS-CoV-2 infection after vaccination achieve high antibody titers in most cases. These data suggest that public health interventions such as vaccine boosting, potentially with more potent vaccine types, may be needed to control the COVID-19 pandemic in Mongolia and worldwide.

Serum Biomarkers Predict Symptom Duration in Long Term COVID-19 Across a Diverse Population (preprint)

Background: Prolonged symptoms after SARS-CoV-2 infection are well-documented. However, which factors influence development of long-term symptoms, how symptoms vary across ethnic groups, and whether long-term symptoms correlate with serologic biomarkers remain elusive. Methods: Adult inpatient and outpatient SARS-CoV-2 RT-PCR positive patients were recruited at Stanford from March 2020 to February 2021. Study participants were seen for in-person visits at diagnosis and every 1-3 months for up to one year after diagnosis; they completed symptom surveys and underwent sampling procedures (blood draw and nasal swab) at each visit. Findings: Our cohort (n=617) ranged from asymptomatic to critical COVID-19 infections. 40% of participants reported at least one symptom associated with COVID-19 six months after diagnosis. Median time from diagnosis to first resolution of all symptoms was 44 days, median time from diagnosis to sustained symptom resolution with no recurring symptoms for one month or longer was 214 days. Serum anti-nucleocapsid IgG level in the first week of infection was predictive of time to symptom resolution. A prior diagnosis of lung disease was associated with longer time to symptom resolution. COVID-19 disease severity, ethnicity, sex, cytomegalovirus (CMV) seropositivity, and remdesivir use did not affect time to sustained symptom resolution. More than 90% of participants had SARS-CoV-2-specific antibody>1000 AU/mL nine months after diagnosis. Interpretation: Our findings showed that all disease severities had a similar risk of developing post-COVID-19 syndrome in an ethnically diverse population. Comorbid lung disease and lower levels of initial IgG response to SARS-CoV-2 nucleocapsid antigen were associated with longer symptom duration. Trial Registration: National clinical trial database NCT04664309.Funding: NIH CTSA grant, U54 NIH Grant, R21 NIEHS, Sean N Parker Center for Allergy and Asthma Research at Stanford University, the Sunshine Foundation, the Crown Foundation, and the Parker Foundation.Declaration of Interest: Dr. Boyd received support for the current manuscript from Meso Scale Discovery and NIH; 418 received consulting fees by Regeneron for expert testimony, has stocks or stock options in 419 AbCellera Biologics; Dr. Chinthrajah reports grants from NIAID, CoFAR, Aimmune, DBV 420 Technologies, Astellas, Regeneron, Stanford Maternal and Child Health Research Institute 421 (MCHRI), and FARE. She is an Advisory Board Member at Alladapt Therapeutics, Novartis, 422 Genentech, Sanofi, Allergenis, and Nutricia; Dr. Manisha Desai received support from Chan 423 Zuckerberg Foundation; Dr. Maecker received grants or contracts from NIH, Bill & Melinda 424 Gates Foundation, Ionis Corporation, Amgen Corporation; Consulting fees from Magarray Corp; 425 payment or honoraria from UCLA, UC Davis; leadership or fiduciary role at Cytek SAB; stocks 426 or stock options at BD Biosciences; Dr. Nadeau reports grants from National Institute of Allergy and Infectious Diseases (NIAID), National Heart, Lung, and Blood Institute (NHLBI), National Institute of Environmental Health Sciences (NIEHS), and Food Allergy Research & Education (FARE); Director of World Allergy Organization (WAO) , Advisor at Cour Pharma, Consultant for Excellergy, Red tree ventures, and Phylaxis, Co-founder of Before Brands, Alladapt, Latitude, and IgGenix; and National Scientific Committee member at Immune Tolerance Network (ITN), and National Institutes of Health (NIH) clinical research centers, outside the submitted work; patents include, “Mixed allergen composition and methods for using the same”, “Granulocyte-based methods for detecting and monitoring immune system disorders”, “Methods and Assays for Detecting and Quantifying Pure Subpopulations of White Blood Cells in Immune System Disorders,” and “Methods of isolating allergen-specific antibodies from humans and uses thereof”; Dr. Benjamin Pinsky received grants or contracts for the present manuscript from MesoScale Diagnostics; Dr. Angele Rogers was a Clinical Trials Advisory Board Member for Merck; Dr. Sindher reports support for the present manuscript from the NIH, Regeneron, DBV Technologies, Aimmune, Novartis, CoFAR, FARE, participated on a DSMB for Astra Zeneca, DBV, and received payment or honorarium from FARE; Neera Ahuja, Maja Artandi, Linda Barman, Catherine Blish, Andra Blomkalns, William Collins, MacKenzie Cox, Linda Geng, Xiaolin Jia, Megan Mahoney, Monali Manohar, Ruth O’hara, Rajan Puri, Katharina Roltgen, Laura Vaughan, Samuel Yang, Shu Cao, Iris Chang, Hena Din, Evan Do, Andrea Fernandez, Alexandra Lee, Natasha Purington, Yael Rosenberg-Hasson, Theo Snow, Daniel Solis, Michelle Verghese, and Yingjie Weng have no conflict of interest.Ethical Approval: This study was reviewed and approved by the Stanford Administrative Panel on Human Subjects in Medical Research.

Safety, immunogenicity and protection provided by unadjuvanted and adjuvanted formulations of recombinant plant-derived virus-like particle vaccine candidate for COVID-19 in non-human primates (preprint)

Although antivirals are important tools to control the SARS-CoV-2 infection, effective vaccines are essential to control the current pandemic. Plant-derived virus-like particle (VLP) vaccine candidates have previously demonstrated immunogenicity and efficacy against influenza. Here we report the immunogenicity and protection induced in macaques by intramuscular injections of VLP bearing SARS-CoV-2 spike protein (CoVLP) vaccine candidate formulated with or without Adjuvant System 03 (AS03) or cytosine phosphoguanine (CpG) 1018. Although a single dose of unadjuvanted CoVLP vaccine candidate stimulated humoral and cell-mediated immune responses, booster immunization (at 28 days after prime) and adjuvants significantly improved both responses with a higher immunogenicity and protection provided by AS03 adjuvanted CoVLP. Fifteen microgram CoVLP adjuvanted with AS03 induced a balanced IL-2 driven response along with IL-4 expression in CD4 T cells and mobilization of CD4 follicular helper cells (Tfh). Animals were challenged by multiple routes (i.e. intratracheal, intranasal and ocular) with a total viral dose of 106 plaque forming units of SARS-CoV-2. Lower viral replication in nasal swabs and broncho-alveolar lavage (BAL) as well as fewer SARS-CoV-2 infected cells and immune cell infiltrates in the lungs concomitant with reduced levels of pro-inflammatory cytokines and chemotactic factors in BAL were observed in the animals immunized with CoVLP adjuvanted with AS03. No clinical, pathologic or virologic evidences of vaccine associated enhanced disease (VAED) were observed in vaccinated animals. CoVLP adjuvanted with AS03 was therefore selected for vaccine development and clinical trials.

Antibody Response to COVID-19 vaccination in Patients Receiving Dialysis (preprint)

Background Patients receiving dialysis may mount impaired responses to COVID19 vaccination. Methods We report antibody response to vaccination from 1140 patients without, and 493 patients with pre-vaccination SARS-CoV-2 RBD antibody. We used commercially available assays (Siemens) to test remainder plasma monthly in association with vaccination date and type, and assess prevalence of absent total receptor binding antibody, and absent or attenuated (index value < 10) semiquantitative receptor binding domain IgG index values. We used Poisson regression to evaluate risk factors for absent or attenuated response to vaccination. Results Among patients who were seronegative versus seropositive before vaccination, 62% and 56% were ≥65 years old, 20% and 24% were Hispanic, and 22% and 23% were Black. Median IgG index values rose steadily over time, and were higher among the seropositive than in the seronegative patients after completing vaccination (150 [25 th , 75 th percentile 23.2, 150.0] versus 41.6 [11.3, 150.0]). Among 610 patients who completed vaccination (assessed ≥14 days later, median 29 days later), the prevalence of absent total RBD response, and absent and attenuated semiquantitative IgG response was 4.4% (95% CI 3.1, 6.4%), 3.4% (2.4, 5.2%), and 14.3% (11.7, 17.3%) respectively. Risk factors for absent or attenuated response included longer vintage of end-stage kidney disease, and lower pre-vaccination serum albumin. Conclusions More than one in five patients receiving dialysis had evidence of an attenuated immune response to COVID19 vaccination. Significance statement Patients receiving dialysis face high likelihood of severe COVID19; at the same time, vaccination may be less efficacious, as prior data indicate impaired immune responses to influenza and Hepatitis B vaccination. We found that 22% of patients receiving dialysis had suboptimal responses to vaccination, irrespective of whether or not they had evidence of prior SARS-CoV-2 infection. Poorer health status and longer duration of end-stage kidney disease increased likelihood of suboptimal response. Ongoing vigilance for COVID19 in dialysis facilities and studies of modified vaccination dosing schedules will be critical to protecting patients receiving dialysis.