Preparation, Characteristics, Toxicity, and Efficacy Evaluation of the Nasal Self-Assembled Nanoemulsion Tumor Vaccine In Vitro and In Vivo

Summary

Here, we present detailed methods for the preparation and evaluation of the nasal self-assembled nanoemulsion tumor vaccine in vitro and in vivo.

Abstract

Epitope peptides have attracted widespread attention in the field of tumor vaccines because of their safety, high specificity, and convenient production; in particular, some MHC I-restricted epitopes can induce effective cytotoxic T lymphocyte activity to clear tumor cells. Additionally, nasal administration is an effective and safe delivery technique for tumor vaccines due to its convenience and improved patient compliance. However, epitope peptides are unsuitable for nasal delivery because of their poor immunogenicity and lack of delivery efficiency. Nanoemulsions (NEs) are thermodynamically stable systems that can be loaded with antigens and delivered directly to the nasal mucosal surface. Ile-Lys-Val-Ala-Val (IKVAV) is the core pentapeptide of laminin, an integrin-binding peptide expressed by human respiratory epithelial cells. In this study, an intranasal self-assembled epitope peptide NE tumor vaccine containing the synthetic peptide IKVAV-OVA_257-264 (I-OVA) was prepared by a low-energy emulsification method. The combination of IKVAV and OVA_257-264 can enhance antigen uptake by nasal mucosal epithelial cells. Here, we establish a protocol to study the physicochemical characteristics by transmission electron microscopy (TEM), atomic force microscopy (AFM), and dynamic light scattering (DLS); stability in the presence of mucin protein; toxicity by examining the cell viability of BEAS-2B cells and the nasal and lung tissues of C57BL/6 mice; cellular uptake by confocal laser scanning microscopy (CLSM); release profiles by imaging small animals in vivo; and the protective and therapeutic effect of the vaccine by using an E.G7 tumor-bearing model. We anticipate that the protocol will provide technical and theoretical clues for the future development of novel T cell epitope peptide mucosal vaccines.

Introduction

As one of the most critical public health innovations, vaccines play a key role in fighting the global burden of human disease¹. For example, at present, more than 120 candidate vaccines for COVID-19 diseases are being tested, some of which have been approved in many countries². Recent reports state that cancer vaccines have effectively improved the progress of clinical cancer treatments because they direct the immune system of cancer patients to recognize antigens as foreign to the body³. Moreover, multiple T cell epitopes located inside or outside tumor cells can be used to design peptide vaccin....

Protocol

The animal experiments were conducted in accordance with the Laboratory Animal—Guideline for ethical review of animal welfare (GB/T 35892-2018) and were approved by the Laboratory Animal Welfare and Ethics Committee of the Third Military Medical University. The mice were euthanized by an intraperitoneal injection of 100 mg/kg of 1% sodium pentobarbital.

1. Preparation of the I-OVA NE

1. Admix 1 mg of monophosphoryl lipid A (MPLA) with 100 µL of DMSO, vortex for 5 min, and allow it to stand for 4 h at room temperature (RT) to dissolve completely.
2. Add Tween 80 and I-OVA quantitatively and mi....

Results

According to the protocol, we completed the preparation and in vitro and in vivo experimental evaluation of the nasal tumor nanovaccine delivery. TEM, AFM, and DLS are effective means for the assessment of the basic characteristics of the surface zeta potential and the particle size of the nanovaccine (Figure 1). BEAS-2B epithelial cells are a useful screening model for the in vitro toxicity testing of nasal vaccines (Figure 2A). The m.......

Discussion

Nanovaccines functionalized with immunocyte membranes have great advantages in disease-targeted therapy, and the side effects are minimized by properties such as unique tumor tropism, the identification of specific targets, prolonged circulation, enhanced intercellular interactions, and low systemic toxicity. They can also be easily integrated with other treatment modules to treat cancers cooperatively^16,20. Desirable attributes can be obtained by controllingphys.......

Materials

Name	Company	Catalog Number	Comments
96-well plates	Corning Incorporated, USA	CLS3922
Bio-Rad 6.0 microplate reader	Bio-Rad Laboratories Incorporated Limited Co., CA, USA	Bio-Rad 6.0
CCK-8 kits	Dojindo, Japan	CK04
Centrifuge 5810 R	Eppendorf, Germany	5811000398
DAPI	Sigma-Aldrich, St. Louis, USA	D9542
fetal bovine serum (FBS)	Hyclone (Life Technology, USA)	SH30088.03
FITC-labeled I-OVA	Shanghai Botai Biotechnology Co., Ltd.	NA
HF 90/240 Incubator	Heal Force, Switzerland	NA
HPLC	Shanghai Botai Biotechology Co., Ltd.	E2695
Inverted Microscope	Nikon,Japan	DSZ5000X
IPC-208	Chong Qing University, China	NA
IVIS system	Caliper Life Science Limited Company	NA
JEM-1230 TEM	JEOL Limited Company of Japan	1230 TEM
Malvern NANO ZS	Malvern Instruments Ltd., UK	NA
MPLA	Invivogen Lit. Co.	tlrl-mpla
Neomycin Sulfate Ointment	Shanghai CP General Pharmaceutical Co. , Ltd.	H31022262
OVA257–264	Shanghai Botai Biotechnology Co., Ltd.	NA
RPMI 1640 medium	Hyclone (Life Technology, USA)	SH30809.01
Synthetic peptide (I-OVA) conjugation of IKVAV-PA	Shanghai Botai Biotechnology Co., Ltd.	NA
Zeiss LSM800 laser scanning confocal fluorescence microscope	Zeiss, Germany	Zeiss LSM800