Matthew Ierullo

UHN: Toronto General Hospital

Immunocompromised patients are predisposed to severe COVID-19. Here we compare homotypic and heterotypic humoral and cellular immune responses to Omicron BA.1 in organ transplant patients across a diverse clinical spectrum. We perform variant-specific pseudovirus neutralization assays for D614G, and Omicron-BA.1, -BA.2, and Delta variants. We also...

In allogeneic stem cell transplant (Allo-SCT) recipients, the cell-mediated and humoral immunogenicity of the 3-dose SARS-CoV-2 vaccination schedule has not been investigated in prospective studies. In a prospective cohort, we recruited 122 Allo-SCT recipients since August 2021, when Ontario began offering a 3-dose vaccine schedule for Allo-SCT rec...

The SARS‐CoV‐2 virus Omicron variant has now supplanted wild‐type virus as the dominant circulating strain globally. Three doses of mRNA COVID‐19 vaccine are recommended for transplant recipients as their primary vaccine series. However, the immunogenicity of mRNA vaccines as they specifically relate to the Omicron variant are not well studied. We...

Delayed dosing intervals are a strategy to immunize a greater proportion of the population. In an observational study, we compared humoral and cellular responses in health care workers receiving two doses of BNT162b2 (Pfizer-BioNTech) vaccine at standard (3- to 6-week) and delayed (8- to 16-week) intervals. In the delayed-interval group, anti-recep...

Background: COVID-19 is more severe in transplant recipients. Variants of concern have supplanted wild-type virus. In transplant recipients, data are limited on 2-dose or 3-dose vaccine immunogenicity against variant viruses. Objective: To assess neutralizing antibody responses against SARS-CoV-2 variants in transplant recipients after 2 and 3 v...

T-cell immunity associated with SARS-CoV-2 infection or vaccination in solid organ transplant recipients (SOTRs) is poorly understood. To address this, we measured T-cell responses in 50 SOTRs with prior SARS-CoV-2 infection. The majority of patients mounted SARS-CoV-2-specific CD4 + T-cell responses against spike (S), nucleocapsid (NP) and membran...

Shortages of COVID-19 vaccines have results in delayed dosing intervals as a strategy to immunize a greater proportion of the population. The effect of this strategy on vaccine immunogenicity is not well studied. Humoral (anti-RBD levels and neutralization) and cellular immune responses were compared in health care workers receiving two doses of BN...

Background: In North America, both mRNA vaccines, Pfizer-BioNTech BNT162b2, and Moderna mRNA-1273, each utilizing a two-dose regimen, have started to be administered to individuals. Methods: We evaluated the quantitative serologic antibody response following administration of either a single dose or both doses of an mRNA SARS-CoV-2 vaccine in a...

Solid organ transplant recipients are at high risk of severe disease from COVID-19. We assessed the immunogenicity of mRNA-1273 vaccine using a combination of antibody testing, surrogate neutralization assays, and T cell assays. Patients were immunized with two doses of vaccine and immunogenicity assessed after each dose using the above tests. CD4+...

Background: Several studies have described the clinical features of COVID-19 in solid organ transplant recipients. However, many have been retrospective or limited to more severe cases (hospitalized) and have not routinely included serial virologic sampling (especially in outpatients) and immunologic assessment. Methods: Transplant patients diag...

Health care workers (HCWs) are at higher risk for SARS-CoV-2 infection and may play a role in transmitting the infection to vulnerable patients and members of the community. This is particularly worrisome in the context of asymptomatic infection. We performed a cross-sectional study looking at asymptomatic SARS-CoV-2 infection in HCWs. We screened...

Lung transplant recipients are at high risk for herpes zoster and preventive measures are a significant unmet need. We investigated the safety and immunogenicity of two doses of a recombinant zoster vaccine (RZV) in lung transplant recipients (≥50 years). We enrolled 50 patients of which 49 received at least one vaccine dose. Anti‐glycoprotein E (g...

Background: Immunization of VZV-seronegative solid organ transplant (SOT) patients using the live-attenuated varicella vaccine is generally contraindicated, leaving no widely applicable immunization option. The recombinant subunit herpes zoster vaccine (RZV) is indicated for VZV seropositive persons to prevent shingles but could potentially also p...

We screened three separate cohorts of healthcare workers for SARS-CoV-2 via nasopharyngeal swab PCR. A seroprevalence analysis using multiple assays was performed in a subgroup. The asymptomatic health care worker cohorts had a combined positivity rate of 29/5776 (0.50%, 95%CI 0.32-0.75) compared to the symptomatic cohort rate of 54/1597 (3.4%) (ra...

Background: Despite annual immunization, solid organ transplant (SOT) patients remain at increased risk for severe influenza infection because of suboptimal vaccine immunogenicity. We aimed to compare the CD4+ and CD8+ T-cell responses of the high-dose (HD) and the standard-dose (SD) trivalent inactivated vaccine. Methods: We collected periphera...

Purpose: The High-dose (HD) influenza vaccine has been shown to induce better humoral immunity than the standard-dose (SD) vaccine in solid organ transplant (SOT) patients. We aimed to evaluate whether the HD vaccine also induced better cell-mediated immunity (CMI) than the SD vaccine. Methods: A subset of patients enrolled in a randomized trial o...

Determining the complete Arabidopsis (Arabidopsis thaliana) protein-protein interaction network is essential for understanding the functional organization of the proteome. Numerous small-scale studies and a couple of large-scale ones have elucidated a fraction of the estimated 300,000 binary protein-protein interactions in Arabidopsis. In this stud...

Seeds respond to multiple different environmental stimuli that regulate germination. Nitrate stimulates germination in many plants but how it does so remains unclear. Here we show that the Arabidopsis NIN-like protein 8 (NLP8) is essential for nitrate-promoted seed germination. Seed germination in nlp8 loss-of-function mutants does not respond to n...

RNA-seq expression data for Col-0 and nlp8-2 seeds imbibed for 6-h in the presence of 1 mM KCl or KNO3.

Localization of NLP7-GFP in response to nitrate. Confocal imaging was performed on NLP7-GFP plants grown on 2.5 mM ammonium succinate for 7 days. Pictures was recorded every 3 seconds after addition of 3 mM nitrate.

Localization of NLP8-GFP in response to nitrate. Confocal imaging was performed on NLP8-GFP plants grown on 2.5 mM ammonium succinate for 7 days. Pictures was recorded every 3 seconds after addition of 3 mM nitrate.

Primers used in this study.

Supplementary Figures 1 - 13

Identifying sets of genes that are specifically expressed in certain tissues or in response to an environmental stimulus is useful for designing reporter constructs, generating gene expression markers, or for understanding gene regulatory networks. We have developed an easy-to-use online tool for defining a desired expression profile (a modificatio...

As part of a recently-funded Genome Canada grant, the Bio-Analytic Resource for Plant Biology (BAR) is preparing to provide seven modules to the Arabidopsis Information Portal: two modules for gene expression (transcript abundance and transcript structure) based on publish microarray and RNA-seq data sets will be made available, via redesigned eFP...