Epidermal Powder Immunization Induces both Cytotoxic T-Lymphocyte and Antibody Responses to Protein Antigens of Influenza and Hepatitis B Viruses

Abstract

Cytotoxic T lymphocytes (CTL) play a vital role in host defense against viral and intracellular bacterial infections. However, nonreplicating vaccines administered by intramuscular injection using a syringe and needle elicit predominantly humoral responses and not CTL responses. Here we report that epidermal powder immunization (EPI), a technology that delivers antigens on 1.5-to 2.5-m gold particles to the epidermis using a needle-free powder delivery system, elicits CTL responses to nonreplicating antigens. Following EPI, a majority of the antigen-coated gold particles were found in the viable epidermis in the histological sections of the target skin. Further studies using transmission electron microscopy revealed the intracellular localization of the gold particles. Many Langerhans cells (LCs) at the vaccination site contained antigen-coated particles, as revealed by two-color immunofluorescence microscopy, and these cells were found in the draining lymph nodes 20 h later. Immune responses to several viral protein antigens after EPI were studied in mice.

A bivalent influenza VLP vaccine confers complete inhibition of virus replication in lungs

“…For virus challenge, isoflurane-anesthetized mice were intranasally infected with 2000 PFU of A/PR8 virus (10× the 50% lethal dose, LD 50 ), 2000 PFU A/WSN virus (10× LD 50 ), 3.5 × 10 6 PFU A/Aichi virus (5× LD50) or 2000 PFU A/Philippines virus (10× LD50) in 50 µl of phosphate-buffered saline (PBS) per mouse at week 4 after the final immunization. Influenza A/Aichi virus has relatively low pathogenicity in mice and high challenge doses were used in previous studies [15,16]. A/ Aichi/2/68-x31virus, a reassortant virus is further reduced in pathogenicity, and thus, higher doses were required to cause mortality in mice.…”

Enabling topical immunization via microporation: a novel method for pain-free and needle-free delivery of adenovirus-based vaccines

“…However, protein-based and conventional flu vaccines have recently been formulated for gene-gun mediated delivery resulting in CTL responses which are not normally produced by standard inoculation of these vaccines. 8,28 Whether or not live vaccines (eg rdAd) can Figure 8 Growth of B16 tumors following immunization with AdhTRP-2 applied to microporated skin. AdhgTRP-2 (5 Â 10 6 pfu/ml) was applied to both microporated and intact skin of C57Bl/6 mice two times, 21 days apart.…”

Targeting epidermal Langerhans cells by epidermal powder immunization

“…Many traditional vaccines such as proteins, peptides, polysaccharides, inactivated pathogens etc are suitable for EPI [44][45][46][47]. Vaccine powders can be prepared by coating antigens onto 1-2 mm gold particles or embedding them into 20-50 mm particles using sugar excipients (trehalose, mannitol, sucrose, or combinations) [44], [47].…”

“…Vaccine powders can be prepared by coating antigens onto 1-2 mm gold particles or embedding them into 20-50 mm particles using sugar excipients (trehalose, mannitol, sucrose, or combinations) [44], [47]. The driving force of the device is pressured helium gas.…”

“…Antigen targeting of LCs in the target tissue following EPI is dependent on whether gold or sugar formulation was used. EPI with the gold formulation results in intracellular deposition of both gold and antigen in the epidermal cells [47]. LCs account for about 3% of the total number of the epidermal cells (Fig 2A), thus, a fraction of particles is directly delivered to LCs.…”