Cellular responses at the application site of a high-density microarray patch delivering an influenza vaccine in a randomized, controlled phase I clinical trial

PLoS One. 2021 Jul 30;16(7):e0255282. doi: 10.1371/journal.pone.0255282. eCollection 2021.

Abstract

Microarray patches (MAPs) have the potential to be a safer, more acceptable, easier to use and more cost-effective method for administration of vaccines when compared to the needle and syringe. Since MAPs deliver vaccine to the dermis and epidermis, a degree of local immune response at the site of application is expected. In a phase 1 clinical trial (ACTRN 12618000112268), the Vaxxas high-density MAP (HD-MAP) was used to deliver a monovalent, split inactivated influenza virus vaccine into the skin. HD-MAP immunisation led to significantly enhanced humoral responses on day 8, 22 and 61 compared with IM injection of a quadrivalent commercial seasonal influenza vaccine (Afluria Quadrivalent®). Here, the aim was to analyse cellular responses to HD-MAPs in the skin of trial subjects, using flow cytometry and immunohistochemistry. HD-MAPs were coated with a split inactivated influenza virus vaccine (A/Singapore/GP1908/2015 [H1N1]), to deliver 5 μg haemagglutinin (HA) per HD-MAP. Three HD-MAPs were applied to the volar forearm (FA) of five healthy volunteers (to achieve the required 15 μg HA dose), whilst five control subjects received three uncoated HD-MAPs (placebo). Local skin response was recorded for over 61 days and haemagglutination inhibition antibody titres (HAI) were assessed on days 1, 4, 8, 22, and 61. Skin biopsies were taken before (day 1), and three days after HD-MAP application (day 4) and analysed by flow-cytometry and immunohistochemistry to compare local immune subset infiltration. HD-MAP vaccination with 15 μg HA resulted in significant HAI antibody titres compared to the placebo group. Application of uncoated placebo HD-MAPs resulted in mild erythema and oedema in most subjects, that resolved by day 4 in 80% of subjects. Active, HA-coated HD-MAP application resulted in stronger erythema responses on day 4, which resolved between days 22-61. Overall, these erythema responses were accompanied by an influx of immune cells in all subjects. Increased cell infiltration of CD3+, CD4+, CD8+ T cells as well as myeloid CD11b+ CD11c+ and non-myeloid CD11b- dendritic cells were observed in all subjects, but more pronounced in active HD-MAP groups. In contrast, CD19+/CD20+ B cell counts remained unchanged. Key limitations include the use of an influenza vaccine, to which the subjects may have had previous exposure. Different results might have been obtained with HD-MAPs inducing a primary immune response. In conclusion, influenza vaccine administered to the forearm (FA) using the HD-MAP was well-tolerated and induced a mild to moderate skin response with lymphocytic infiltrate at the site of application.

Publication types

  • Clinical Trial, Phase I
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Antigens, CD / immunology
  • CD4-Positive T-Lymphocytes / immunology*
  • CD8-Positive T-Lymphocytes / immunology*
  • Drug Delivery Systems*
  • Female
  • Humans
  • Immunity, Cellular / drug effects*
  • Influenza A Virus, H1N1 Subtype / immunology*
  • Influenza Vaccines / administration & dosage*
  • Influenza Vaccines / immunology
  • Influenza, Human / immunology
  • Influenza, Human / prevention & control
  • Male
  • Middle Aged
  • Skin / immunology*
  • Time Factors

Substances

  • Antigens, CD
  • Influenza Vaccines

Grants and funding

The study was entirely funded by Vaxxas Pty Ltd, Brisbane QLD 4102 Australia, www.vaxxas.com. Vaxxas, through its employees, was therefore directly involved in the study design, data collection, analysis as well as preparation of his manuscript for publication - AHF is an employee of Vaxxas Pty Ltd and is the corresponding author of the manuscript. AHF was directly involved in the study design, data collection, as well as preparation of his manuscript for publication and decision to publish. - ACID and KW are the joint-lead authors of this manuscript and employees of Vaxxas Pty Ltd, and were directly involved in the study design, sample processing, data collection, analysis as well as preparation of his manuscript for publication. ACID is an inventor on patents licensed to Vaxxas Pty Ltd. - JWW, CDA, PT, JH and GJPF received consulting fees from Vaxxas Pty Ltd to support their contribution to this research. They were directly involved in the study design, data collection, data interpretation as well as preparation of the manuscript for publication. PT was involved in data analysis, data interpretation as well as editing of the manuscript for publication. - JWW and MV are employees of the University of Queensland. They carried out assay development on a contract basis paid for by Vaxxas Pty Ltd, and were directly involved in the experimental design, sample processing, data analysis as well as preparation of the manuscript for publication. - JDL is an employee of Nucleus Network, which carried out the clinical trial (trial site) on a contract basis paid for by Vaxxas Pty Ltd. JDL was directly involved in sample processing, data interpretation as well as preparation of the manuscript for publication. - SR and JB are employed by Seqirus, which provided Vaxxas with vaccine for the clinical trial. They were involved in preparation of his manuscript for publication but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.