To the Editor: Immunocompromised recipients of allogeneic hematopoietic stem cell transplant (HCT) are at increased risk of severe COVID-19.1 During the first year of a successful HCT, circulating T-cells arise from donor CD34+ cells and can react to antigens exposed to the donor through natural infection or vaccination before transplantation. Therefore, donor pathogen exposure or vaccination pre-graft can be beneficial to the recipient when mounting cellular and humoral response to augment immune reconstitution and control post-HCT natural infection or increase vaccination responses.2 Here, we present evidence of transfer and expansion of SARS-CoV-2-specific adaptive immunity from three matched unrelated donors (MUDs), vaccinated with licensed COVID-19 vaccines to unvaccinated and vaccinated recipients. The 10/10 matched (with permissive HLA-DPB1 locus mismatch) MUDs and their recipients did not have COVID-19 history nor developed active infection through study completion (d + 180). All three recipients engrafted and achieved full donor chimerism (>95%)3 by d + 30. The patient from MUD/R1 pair (Table 1S) was a 29-year-old Hispanic male, with body mass index of 40.07 kg/m2, hypertension, diabetes, diagnosed with Philadelphia like B-cell acute lymphoblastic leukemia, with cytokine receptor-like factor 2 rearrangement. The mRNA-1273 vaccinated MUD donor was a 33-year-old male. The recipient underwent a myeloablative HCT soon after CD-19 CAR T-cell therapy, while in second complete remission (CR2) with negative measurable residual disease (MRD), using fractionated total body irradiation with etoposide. He received GVHD prophylaxis of tacrolimus and sirolimus (tacro/siro). He developed grade 1 skin GVHD around d + 24, which resolved with topical therapy. He did not receive a COVID-19 vaccine because prior to HCT, the patient was unstable and not ambulatory. Patient from MUD/R2 pair was a 74-year-old Caucasian male with history of hypertension, diagnosed with acute myeloid leukemia with deletion Y and SRSF2 mutation, who was in CR1 with negative MRD after receiving hypomethylating agent and venetoclax. The BNT162b2 mRNA vaccinated MUD donor was a 30-year-old female. The recipient underwent reduced intensity HCT using fludarabine and melphalan conditioning (FM), with tacro/siro GVHD prophylaxis in combination with itacitinib JAK-1 inhibitor (NCT04339101). He developed mild chronic GVHD of skin and liver around d + 180. He received a single JNJ-78436735 vaccine dose pre-HCT (d-145). Patient from MUD/R3 pair was a 65-year-old Caucasian female with hypertension and myelodysplastic syndrome/myeloproliferative neoplasm associated with JAK2, ASXL1, and SRSF2 mutations. The BNT162b2 mRNA vaccinated MUD donor was a 33-year-old male. The recipient underwent reduced intensity HCT using FM, followed by tacro/siro with itacitinib for GVHD prophylaxis. She received the BNT162b2 mRNA COVID-19 vaccine pre- (d-74) and post-HCT (d + 112 and d + 133). On d + 165, the patient received tixagevimab co-packaged with cilgavimab for COVID-19 prophylaxis. All three MUD donors (Figure 1) developed SARS-CoV-2-specific neutralizing antibodies (NAbs), following vaccination with either the BNT162B2 vaccine or the JNJ-78436735 (Table 1S). Serum levels of receptor-binding domain (RBD)- and Spike (S)-specific antibodies were also similar in the three donors. Low levels of Nucleocapsid (N)-specific IgG were detected in donors from MUD/R1 and MUD/R2 pairs. IgM levels were minimal since all donors received the first vaccine injection >2 months before graft collection. Functional SARS-CoV-2-specific T-cells were mainly CD137+CD3+CD4+, and higher levels were measured in pair 2 donor compared to the other two donors. N-specific T-cells were detectable in pair 1 and 2 donors, analogously to their respective humoral response pattern, which may indicate undocumented exposure to SARS-CoV-2, in these subjects. S-specific IFN-γ had comparable levels in all three donors. SARS-CoV-2-specific CD137+ T-cells were detected early post-HCT in all three recipients and expanded during immune reconstitution (Figure 1A,B). MUD/R1 pair patient, who did not receive COVID-19 vaccine, had measurable functionally activated S-specific CD137+CD3+CD4+ T-cells early post-HCT (d + 30). They subsequently declined and then gradually expanded to levels comparable to those of the donor by d + 150 when patient's lymphopenia resolved. S-specific IFN-γ was detectable starting d + 60 and markedly increased through d + 150. Frequencies of both S- and N-specific donor derived CD137+CD3+CD4+ T-cells were 3–5 times lower in the MUD/R2 recipient than in the donor, by d + 30. However, during immune reconstitution, they steadily increased, and by six months post-transplant, they surpassed levels detected in the donor blood draw. Moreover, low but measurable levels of S-specific CD137+CD8+ T-cells were detected in the MUD/R2 pair, which peaked by study end in the recipient. T-cells were actively producing high levels of S-specific IFN-γ, though the patient remained lymphopenic, and at times also leukopenic until d + 150. S-specific CD137+CD3+CD4+ T-cells were detectable early post-HCT in the recipient of the MUD/R3 pair. T-cells consistently expanded from the donor graft during immune reconstitution, and further increased when post-transplant COVID-19 vaccine was administered. S-specific CD137+CD3+CD8+ and N-specific CD137+CD3+CD4+ T-cells proliferation peaked at around three months post-HCT vaccination. Very high levels of S-specific IFN-γ and modest levels of S-specific IL-4 were detected after the first post-HCT COVID-19 vaccine dose. Functionally activated SARS-CoV-2-specific T-cells were characterized for their memory phenotypes (Figure 1S). Most of the S- and N-specific CD137+CD3+CD4+ were central memory T-cells (TCM) expressing high levels of CD28 and minimal levels of CD45RA. S- and N-specific CD137+CD3+CD4+ T-cells exhibited stable phenotypes, with modest increasing levels in TCM for S-specific CD137+CD3+CD4+ T-cells in all three MUD/R pairs. For MUD/R pair 2 and 3 patients, frequency of S-specific CD137+ CD3+ CD8+ T-cells was at some time points ≥0.2%, consequently memory phenotype could be measured9. Persistent levels of less differentiated effectors T-cell subsets (TEMRA) with expansion plasticity phenotypic signature (CD45RA+ CD28−) were detected in the CD8 arm of functionally activated S-specific T-cells. Antibody-mediated SARS-CoV-2 specific immunity was detected in all three MUD/R pairs (Figure 1A,C). Transfer of donor-derived SARS-CoV-2 specific humoral immunity can be surmised for MUD/R1 pair, since no COVID-19 infection nor vaccination was reported for the patient. Declining levels of S- and RBD- IgG binding antibodies were measurable through 6 months post-HCT. Transfer of N-IgG and low levels of SARS-CoV-2 specific NAbs was detectable only on d + 30. In MUD/R2 and MUD/R3 pairs in whom recipients received pre-HCT SARS-CoV-2 vaccines, early post-HCT detection of adaptive humoral immunity was probably of both donor and recipient origin. In recipient of MUD/R2 pair, lymphopenia resolution (Figure 1B) may have led to the expansion of donor-derived SARS-CoV-2-specific B-cells with consequent increase in S- and RBD-IgG binding titers and NAbs levels by d + 150. In MUD/R3 pair, post-HCT COVID-19 vaccination of the recipient greatly boosted both S- and RBD-IgG binding titers and NAbs which peaked by d + 150. Low titer levels of SARS-CoV-2-specific IgM antibodies were also detectable following COVID-19 vaccination. Subsequent administration of tixagevimab/cilgavimab at d + 165 did not further increase levels of SARS-CoV-2 adaptive humoral immunity in the recipient. To our knowledge, this is the first reported evidence of donor-derived SARS-CoV-2 immune transfer, expansion, and vaccine boosting in HCT recipients. Substantial SARS-CoV-2-specific IFN-γ was measurable in all three HCT recipients. In contrast, IL-4 levels remained minimal which was indicative of a polarized Th1 response, associated with protection from severe COVID-19.4 Memory phenotype for both S- and N-specific CD137+ T-cells showed elevated frequencies of TCM, which can home to lymph nodes, where they help B cells undergo affinity maturation.4 Increasing percentages of S-specific CD137+ CD8+ TEMRA effectors characterized by proliferative and self-renewal capacity were also detected, which are typically found in convalescing COVID-19 patients and vaccinated individuals.4 Our data confirm recent studies suggesting that T-cell responses in immunosuppressed patients can be preserved and may provide an essential role in vaccine-mediated protection.5 Hence, the prompt surge in levels of donor-derived functional SARS-CoV-2-specific T-cells and IFN-γ in MUD/R3 patient indicate that in T-cell replete HCT recipients, a graft from a vaccinated donor can favor successful booster-like cellular response even early post-HCT, when humoral responses are blunted by ongoing immunosuppressive regimens. In the three recipients, NAb titers remained low or undetectable early post-HCT, confirming delayed B-cell functional reconstitution and adaptive humoral immune recovery post-HCT. Increases in SARS-CoV-2-specific IgG and NAb followed SARS-CoV-2-specific CD4 T-cell reconstitution. The critical role of CD4 T-cells6 in promoting robust, long lived SARS-CoV-2-specific antibody levels, and in response to mRNA vaccines has been shown including in HCT and cellular therapy recipients, in whom COVID-19 vaccines are not precluded even when B-cell aplasia occurs. In summary, pre-HCT vaccination of MUD/R2 and MUD/R3 pairs potentiated immune reconstitution and stimulated proliferation of functional donor-derived T-cells, which were likely the primary cause of the robust SARS-CoV-2-specific humoral responses observed in the recipients. Detection of low levels of S-specific and RBD-specific IgM after COVID-19 re-vaccination could be explained as the inability of the immunosuppressed patient to mount an efficient antibody response. No effect of tixagevimab/cilgavimab prophylaxis was observed in MUD/R3 patient, likely because the treatment was administered immediately after the post-HCT vaccination rise in humoral response. Our data suggest that choosing a donor with SARS-CoV-2-specific immunity could be decisive as an alternative prophylaxis strategy to mitigate COVID-19 severity in HCT recipients and can promote a functional vaccine response early post-HCT. Finally, none of the three recipients described in this report developed COVID-19 post-HCT, which is a limitation of this study. Therefore, further investigation in different transplant settings is needed to verify that SARS-CoV-2-specific adoptive immunity from a COVID-19-seropositive donor is protective for the recipient after transplantation. Such clinical studies can constitute a critical, essential step toward improvement of the remarkably poor recovery from COVID-19 observed in the HCT setting. Don J. Diamond and Stephen J. Forman thanks The Carol Moss Foundation for supporting COVID-19 research in HCT recipients. This research was partly funded by a National Institutes of Health, National Cancer Institute (NCI) Support Grant (P50 CA107399-12) to Stephen J. Forman; Don J. Diamond was partially supported by National Institute of Allergy and Infectious Diseases (NIAID) U19AI128913, NCI CA181045 and NIAID U01AI163090. We would like to thank Alba Grifoni and Alessandro Sette (Center for Infectious Disease and Vaccine Research, La Jolla Institute for Immunology, La Jolla) for kindly providing SARS-CoV-2 Proteome and Spike megapool peptide libraries; COH MUD program coordinators; NMDP staff and research coordinators for national and international MUD enrollment and specimens logistics; and the entire COH HCT team involved in the care of patients from MUD/R1, 2 and 3 pairs without whose support this study could not have been conducted. Corinna La Rosa received consulting fees and research funding from Helocyte Inc.; Don J. Diamond consulting fees, patent royalties, research funding, and fees for serving on the advisory board of Helocyte Inc. In addition, Don J. Diamond has two patents 8 580 276 and 9 675 689 that are licensed to Helocyte. Don J. Diamond and Flavia Chiuppesi are co-inventors of the Patent Cooperation Treaty (PCT) application that covers the development of a COVID-19 vaccine (PCT/US2021/032821) licensed to GeoVax Labs Inc. Don J. Diamond receives consulting fees and research support from GeoVax Labs Inc. Ryotaro Nakamura is a consultant for Omeros, Bluebird, Viracor Eurofins, Magenta Therapeutics, Kadmon, Napajen Pharma; received research funding from Helocyte, Miyarisan Pharmaceutical; and travel, accommodations, expenses from Kyowa Hakko Kirin, Alexion Pharmaceuticals. S.D. is a consultant for Merck, Allovir, and Aseptiscope; Advisory board for Merck; and investigator for Allovir, Merck, Ansun, Gilead, Janssen, Shire/Takeda, and on speakers bureau of Merck and Astellas. The remaining authors declare no relevant competing financial interests. This study is registered on clinicaltrials.gov, as NCT04666025. The data that support the findings of this study are available from the corresponding author upon reasonable request. Appendix S1 Supporting Information Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.
Second-generation COVID-19 vaccines could contribute to establish protective immunity against SARS-CoV-2 and its emerging variants. We developed COH04S1, a synthetic multiantigen modified vaccinia Ankara-based SARS-CoV-2 vaccine that co-expresses spike and nucleocapsid antigens. Here, we report COH04S1 vaccine efficacy in animal models. We demonstrate that intramuscular or intranasal vaccination of Syrian hamsters with COH04S1 induces robust Th1-biased antigen-specific humoral immunity and cross-neutralizing antibodies (NAb) and protects against weight loss, lower respiratory tract infection, and lung injury following intranasal SARS-CoV-2 challenge. Moreover, we demonstrate that single-dose or two-dose vaccination of non-human primates with COH04S1 induces robust antigen-specific binding antibodies, NAb, and Th1-biased T cells, protects against both upper and lower respiratory tract infection following intranasal/intratracheal SARS-CoV-2 challenge, and triggers potent post-challenge anamnestic antiviral responses. These results demonstrate COH04S1-mediated vaccine protection in animal models through different vaccination routes and dose regimens, complementing ongoing investigation of this multiantigen SARS-CoV-2 vaccine in clinical trials.
Abstract Second-generation COVID-19 vaccines could contribute to establish protective immunity against SARS-CoV-2 and its emerging variants. We developed COH04S1, a synthetic multiantigen Modified Vaccinia Ankara-based SARS-CoV-2 vaccine that co-expresses spike and nucleocapsid antigens. Here, we report COH04S1 vaccine efficacy in animal models. We demonstrate that intramuscular or intranasal vaccination of Syrian hamsters with COH04S1 induces robust Th1-biased antigen-specific humoral immunity and cross-neutralizing antibodies (NAb) and protects against weight loss, lower respiratory tract infection, and lung injury following intranasal SARS-CoV-2 challenge. Moreover, we demonstrate that single-dose or two-dose vaccination of non-human primates with COH04S1 induces robust antigen-specific binding antibodies, NAb, and Th1-biased T cells, protects against both upper and lower respiratory tract infection following intranasal/intratracheal SARS-CoV-2 challenge, and triggers potent post-challenge anamnestic antiviral responses. These results demonstrate COH04S1-mediated vaccine protection in animal models through different vaccination routes and dose regimens, complementing ongoing investigation of this multiantigen SARS-CoV-2 vaccine in clinical trials.
Abstract Antimicrobial resistance is a global public health concern, and livestock play a significant role in selecting for resistance and maintaining such reservoirs. Here we study the succession of dairy cattle resistome during early life using metagenomic sequencing, as well as the relationship between resistome, gut microbiota, and diet. In our dataset, the gut of dairy calves serves as a reservoir of 329 antimicrobial resistance genes (ARGs) presumably conferring resistance to 17 classes of antibiotics, and the abundance of ARGs declines gradually during nursing. ARGs appear to co-occur with antibacterial biocide or metal resistance genes. Colostrum is a potential source of ARGs observed in calves at day 2. The dynamic changes in the resistome are likely a result of gut microbiota assembly, which is closely associated with diet transition in dairy calves. Modifications in the resistome may be possible via early-life dietary interventions to reduce overall antimicrobial resistance.
Routine screening of asymptomatic newborns allows detection and treatment of infants affected by congenital hypothyroidism. Implemented by legislation enacted in 1980, the Texas Newborn Screening Program detects 120-150 cases of primary hypothyroidism a year. The responsibility and, ultimately, the success of hypothyroid screening in the newborn period largely depends upon the medical provider, necessitating a clear understanding of the screening process, appropriate diagnostic tests for confirmation, and timely treatment.
Cell-mediated immunity may contribute to providing protection against SARS-CoV-2 and its variants of concern (VOC). We developed COH04S1, a synthetic multiantigen modified vaccinia Ankara (MVA)-based COVID-19 vaccine that stimulated potent spike (S) and nucleocapsid (N) antigen-specific humoral and cellular immunity in a phase 1 clinical trial in healthy adults. Here, we show that individuals vaccinated with COH04S1 or mRNA vaccine BNT162b2 maintain robust cross-reactive cellular immunity for six or more months post-vaccination. Although neutralizing antibodies induced in COH04S1- and BNT162b2-vaccinees showed reduced activity against Delta and Omicron variants compared to ancestral SARS-CoV-2, S-specific T cells elicited in both COH04S1- and BNT162b2-vaccinees and N-specific T cells elicited in COH04S1-vaccinees demonstrated potent and equivalent cross-reactivity against ancestral SARS-CoV-2 and the major VOC. These results suggest that vaccine-induced T cells to S and N antigens may constitute a critical second line of defense to provide long-term protection against SARS-CoV-2 VOC.
COH04S1, a synthetic attenuated modified vaccinia virus Ankara vector co-expressing SARS-CoV-2 spike and nucleocapsid antigens, was tested for safety and immunogenicity in healthy adults.This combined open-label and randomised, phase 1 trial was done at the City of Hope Comprehensive Cancer Center (Duarte, CA, USA). We included participants aged 18-54 years with a negative SARS-CoV-2 antibody and PCR test, normal haematology and chemistry panels, a normal electrocardiogram and troponin concentration, negative pregnancy test if female, body-mass index of 30 kg/m2 or less, and no modified vaccinia virus Ankara or poxvirus vaccine in the past 12 months. In the open-label cohort, 1·0 × 107 plaque-forming units (PFU; low dose), 1·0 × 108 PFU (medium dose), and 2·5 × 108 PFU (high dose) of COH04S1 were administered by intramuscular injection on day 0 and 28 to sentinel participants using a queue-based statistical design to limit risk. In a randomised dose expansion cohort, additional participants were randomly assigned (3:3:1), using block size of seven, to receive two placebo vaccines (placebo group), one low-dose COH04S1 and one placebo vaccine (low-dose COH04S1 plus placebo group), or two low-dose COH04S1 vaccines (low-dose COH04S1 group). The primary outcome was safety and tolerability, with secondary objectives assessing vaccine-specific immunogenicity. The primary immunological outcome was a four times increase (seroconversion) from baseline in spike-specific or nucleocapsid-specific IgG titres within 28 days of the last injection, and seroconversion rates were compared with participants who received placebo using Fisher's exact test. Additional secondary outcomes included assessment of viral neutralisation and cellular responses. This trial is registered with ClinicalTrials.gov, NCT046339466.Between Dec 13, 2020, and May 24, 2021, 56 participants initiated vaccination. On day 0 and 28, 17 participants received low-dose COH04S1, eight received medium-dose COH04S1, nine received high-dose COH04S1, five received placebo, 13 received low-dose COH04S1 followed by placebo, and four discontinued early. Grade 3 fever was observed in one participant who received low-dose COH04S1 and placebo, and grade 2 anxiety or fatigue was seen in one participant who received medium-dose COH04S1. No severe adverse events were reported. Seroconversion was observed in all 34 participants for spike protein and 32 (94%) for nucleocapsid protein (p<0·0001 vs placebo for each comparison). Four times or more increase in SARS-CoV-2 neutralising antibodies within 56 days was measured in nine of 17 participants in the low-dose COH04S1 group, all eight participants in the medium-dose COH04S1 group, and eight of nine participants in the high-dose COH04S1 group (p=0·0035 combined dose levels vs placebo). Post-prime and post-boost four times increase in spike-specific or nucleocapsid-specific T cells secreting interferon-γ was measured in 48 (98%; 95% CI 89-100) of 49 participants who received at least one dose of COH04S1 and provided a sample for immunological analysis.COH04S1 was well tolerated and induced spike-specific and nucleocapsid-specific antibody and T-cell responses. Future evaluation of this COVID-19 vaccine candidate as a primary or boost vaccination is warranted.The Carol Moss Foundation and City of Hope Integrated Drug Development Venture programme.
Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has emerged as a global pandemic that upended existing protocols and practices, including those for allogeneic hematopoietic stem cell transplantation (HCT). Here, we describe the successful clinical course and multiple key interventions administered to an acute lymphoblastic leukemia patient, who tested SARS-CoV-2 positive by reverse transcriptase polymerase chain reaction on day -1 of matched unrelated donor (SARS-CoV-2 immunoglobulin G negative) T-cell-replete HCT. This experience allowed for implementing a virologic and immunomonitoring panel to characterize the impact of SARS-CoV-2 on the recipient's nascent humoral and cellular immune response. The finding of robust, functional, and persistent levels of SARS-CoV-2-specific T cells, starting early after transplant was unexpected, and in combination with the clinical strategy, may have contributed to the favorable outcome. Additionally, it is plausible that preexisting cross-reactive endemic coronavirus immunity in the allogeneic graft reduced recipient susceptibility to COVID-19 disease. This case supports the critical role that T-cell responses may play in mitigating SARS-CoV-2 infection, even in the context of transplant immunosuppression, in which reconstitution of humoral response is commonly delayed. Interventional approaches to transfer SARS-CoV-2-specific cellular immunity such as HCT donor vaccination and adaptive cellular therapy could be of benefit.
Currently circulating SARS-CoV-2 variants acquired convergent mutations at receptor-binding domain (RBD) hot spots. Their impact on viral infection, transmission, and efficacy of vaccines and therapeutics remains poorly understood. Here, we demonstrate that recently emerged BQ.1.1. and XBB.1 variants bind ACE2 with high affinity and promote membrane fusion more efficiently than earlier Omicron variants. Structures of the BQ.1.1 and XBB.1 RBDs bound to human ACE2 and S309 Fab (sotrovimab parent) explain the altered ACE2 recognition and preserved antibody binding through conformational selection. We show that sotrovimab binds avidly to all Omicron variants, promotes Fc-dependent effector functions and protects mice challenged with BQ.1.1, the variant displaying the greatest loss of neutralization. Moreover, in several donors vaccine-elicited plasma antibodies cross-react with and trigger effector functions against Omicron variants despite reduced neutralizing activity. Cross-reactive RBD-directed human memory B cells remained dominant even after two exposures to Omicron spikes, underscoring persistent immune imprinting. Our findings suggest that this previously overlooked class of cross-reactive antibodies, exemplified by S309, may contribute to protection against disease caused by emerging variants through elicitation of effector functions.
