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A variety of expression vectors (e.g., Escherichia coli, Pichia pastoris and DNA) have been used to express Pvs25 protein which has been administered alone or in combination with adjuvants

To date these studies suggest that the recombinant protein currently requires both not only linear, but conformation dependent epitopes, and a strong adjuvant to induce transmission-blocking antibodies.

Intranasal and intramuscular immunization with Baculovirus Dual Expression System-based Pvs25 vaccine substantially blocks Plasmodium vivax transmission

Recently, we have developed a new vaccine vector system based on the baculovirus Autographa californica nucleopolyhedrosis virus (AcNPV) termed the “Baculovirus Dual Expression System”, which drives expression of vaccine candidate antigens by a dual promoter that consists of tandemly arranged baculovirus-derived polyhedrin and mammalian-derived CMV promoters. It has been shown that AcNPV, an enveloped double-stranded DNA virus that naturally infects insects, possesses strong adjuvant properties that can activate dendritic cell-mediated innate immunity

Mucosal vaccines have several attractive features compared with parenteral vaccines (e.g., safety, cost-effectiveness and ease of administration), but studies on their use have been limited almost exclusively to protection against mucosally transmitted pathogens. We provide evidence that i.n. immunization is a feasible alternative for preventing malaria, which is transmitted through non-mucosal routes

These results are consistent with our previous work showing that intranasal immunization with the baculovirus-based vaccine induced strong systemic humoral immune responses with high titres of antigen-specific antibodies and conferred complete protection against malaria blood-stage challenge

which can induce immunological memory against heterologous antigens in a rodent model; however, it is precluded from clinical use due to its enterotoxicity and potential hazardous effects on olfactory nerves [22]. In contrast, a baculovirus-based delivery system may offer an attractive immunization method, as AcNPV exhibits low cytotoxicity and is incapable of replication in mammalian cells

The data described here adds to previously presented data showing the significant potential of the baculovirus dual expression system against the blood stages of the parasite

but also demonstrates clearly its ability to induce antibodies against the ookinete surface protein Pvs25, and to elicit a transmission-blocking immune response against the P. vivax isolates from endemic areas, and a transgenic rodent malaria parasite model in preliminary studies.

One was SMFA on peripheral blood from P. vivax infected patients.

Foreign immunogens or peptides can be displayed on the envelope of AcMNPV by fusion with the baculovirus major envelope protein gp64

Baculoviruses have strong adjuvant activity to promote humoral and cellular immune responses against coadministered antigens, activate dendritic cells maturation, induce the production of cytokines, chemokines, and type I IFNs

There are two influenza vaccine approaches licensed in the US; the inactivated, split vaccine and the live-attenuated virus vaccine. Inactivated vaccines can efficiently induce humoral immune responses but generally only poor cellular immune responses.

Therefore, influenza HA can be displayed on the surface of baculovirus

virus-like particle (VLP)

Even though cellular immune responses cannot confer sterilizing immunity, they are able to reduce the severity of infection and lower morbidity and mortality rates [47], and antigen-specific memory T cells are able to rapidly respond to a secondary virus infection [45]. Furthermore, cellular immune responses to the conserved epitopes contained in vaccines may provide cross-protective immunity against different subtypes of influenza virus infection

To confirm that each HA was incorporated on the envelope of baculoviruses, supernatants from infected Sf9 cells were used to perform hemagglutination assay

Most BV display strategies rely on gp64 protein which is the major envelope protein of baculovirus.

Manufacturers for the most part still make flu vaccines the way they did in World War II: in chicken eggs.