Statistical method for testing the neutral mutation hypothesis by DNA polymorphism.

The formulation and delivery of biopharmaceutical drugs, such as monoclonal antibodies and recombinant proteins, poses substantial challenges owing to their large size and susceptibility to degradation. In this Review we highlight recent advances in formulation and delivery strategies — such as the use of microsphere-based controlled-release technologies, protein modification methods that make use of polyethylene glycol and other polymers, and genetic manipulation of biopharmaceutical drugs — and discuss their advantages and limitations. We also highlight current and emerging delivery routes that provide an alternative to injection, including transdermal, oral and pulmonary delivery routes. In addition, the potential of targeted and intracellular protein delivery is discussed.

Overcoming the challenges in administering biopharmaceuticals: formulation and delivery strategies

Microneedles for drug and vaccine delivery.

Recent progress in tumor pH targeting nanotechnology

Virus-like particle (VLP) technology is a promising approach for the construction of novel vaccines, diagnostic tools, and gene therapy vectors. Initially, VLPs were primarily derived from non-enveloped icosahedral or helical viruses and proved to be viable vaccine candidates due to their effective presentation of epitopes in a native conformation. VLP technology has also been used to prepare chimeric VLPs decorated with genetically fused or chemically coupled epitope stretches selected from immunologically defined target proteins. However, structural constraints associated with the rigid geometrical architecture of icosahedral or helical VLPs pose challenges for the expression and presentation of large epitopes. Complex VLPs derived from non-symmetric enveloped viruses are increasingly being used to incorporate large epitopes and even full-length foreign proteins. Pleomorphic VLPs derived from influenza or other enveloped viruses can accommodate multiple full-length and/or chimeric proteins that can be rationally designed for multifunctional purposes, including multivalent vaccines. Therefore, a second generation of VLP carriers is represented by complex particles reconstructed from natural or chimeric structural proteins derived from complex enveloped viruses. Further development of safe and efficient VLP nanotechnology may require a rational combination of both approaches.

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Development of Virus-Like Particle Technology from Small Highly Symmetric to Large Complex Virus-Like Particle Structures

Recurrent outbreaks of highly pathogenic avian influenza virus pose the threat of pandemic spread of lethal disease and make it a priority to develop safe and effective vaccines. Influenza virus-like particles (VLPs) have been suggested to be a promising vaccine approach. However, VLP-induced immune responses, and their roles in inducing memory immune responses and cross-protective immunity have not been investigated. In this study, we developed VLPs containing influenza virus A/PR8/34 (H1N1) hemagglutinin (HA) and matrix (M1) proteins and investigated their immunogenicity, long-term cross-protective efficacy, and effects on lung proinflammatory cytokines in mice. Intranasal immunization with VLPs containing HA induced high serum and mucosal antibody titers and neutralizing activity against PR8 and A/WSN/33 (H1N1) viruses. Mice immunized with VLPs containing HA showed little or no proinflammatory lung cytokines and were protected from a lethal challenge with mouse-adapted PR8 or WSN viruses even 5 months postimmunization. Influenza VLPs induced mucosal immunoglobulin G and cellular immune responses, which were reactivated rapidly upon virus challenge. Long-lived antibody-secreting cells were detected in the bone marrow of immunized mice. Immune sera administered intranasally were able to confer 100% protection from a lethal challenge with PR8 or WSN, which provides further evidence that anti-HA antibodies are primarily responsible for preventing infection. Taken together, these results indicate that nonreplicating influenza VLPs represent a promising strategy for the development of a safe and effective vaccine to control the spread of lethal influenza viruses.

Virus-Like Particle Vaccine Induces Protective Immunity against Homologous and Heterologous Strains of Influenza Virus

Formulation and coating of microneedles with inactivated influenza virus to improve vaccine stability and immunogenicity.

Background
Current influenza vaccines based on the hemagglutinin protein are strain specific and do not provide good protection against drifted viruses or emergence of new pandemic strains. An influenza vaccine that can confer cross-protection against antigenically different influenza A strains is highly desirable for improving public health.

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Influenza virus-like particles containing M2 induce broadly cross protective immunity.

Influenza vaccines based on virus-like particles.

Recovery from live influenza virus infection is known to induce heterosubtypic immunity. In contrast, immunity induced by inactivated vaccines is predominantly subtype specific. In this study, we investigated the heterosubtypic protective immunity induced by inactivated influenza virus. Intranasal immunization of mice with inactivated influenza virus A/PR8 (H1N1) provided complete protection against the homologous virus and a drift virus within the same subtype, A/WSN (H1N1), but not against the heterosubtypic virus A/Philippines (H3N2). However, coadministration of inactivated virus with cholera toxin as an adjuvant conferred complete heterosubtypic protection, without observed illness, even under conditions of CD4 + or CD8 + T-cell depletion. Analysis of immune correlates prior to challenge and postchallenge indicated that humoral immune responses with cross-neutralizing activity in lungs and in sera play a major role in conferring protective immunity against heterosubtypic challenge. This study has significant implications for developing broadly cross-reactive vaccines against newly emerging pathogenic influenza viruses.

Fu-Shi Quan

Papers

Virus-Like Particle Vaccine Induces Protective Immunity against Homologous and Heterologous Strains of Influenza Virus

Formulation and coating of microneedles with inactivated influenza virus to improve vaccine stability and immunogenicity.

Influenza virus-like particles containing M2 induce broadly cross protective immunity.

Influenza vaccines based on virus-like particles.

Induction of Heterosubtypic Immunity to Influenza Virus by Intranasal Immunization