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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.

Selective degradation with RNase I demonstrates that GCXV has a single-stranded RNA genome.

reverse genetics system

no Illumina reads aligned to the segment 5 sequences from the other isolates, and no contigs from ACH27 exhibited significant similarity to the segment 5 sequences from the other isolates. Therefore, segment 5 appears to be absent from ACH27 and TR7094.

However, only four segments were assembled for ACH27 and TR7094 (genome size ∼10.6 kb). For these two isolates, the four assembled segments corresponded to the four largest segments assembled in the other isolates (Figure 1Figure 1, segments 1–4).

The phylogeny inferred from segment 5 is also inconsistent with those of the other segments. In addition to the absence of this segment in TR7094 and ACH27, this segment exhibited very low levels of nt divergence (0.4%–2.3%), with most sequence variations only present in a single isolate.

with each genome segment separately packaged into virions. Although multicomponent genomes are relatively common among RNA viruses that infect plants and fungi, this method of genome organization has not previously been seen in animal viruses (

RNA extracted from purified GCXV particles confirmed the presence of a segmented genome (

The mosquito pools for both ACH27 and TR7094 contained multiple viruses capable of replicating in mosquito cells, so we were unable to obtain pure cultures for these isolates (

Nuclease digestion assays (Figure 1Figure 1B), along with 5′ and 3′ rapid amplification of cDNA ends (RACE), confirmed that all five genome segments were single-stranded, positive-sense RNA (ssRNA+).

all five segments, (2) segments 1–4, and (3) segments 2–5

the number of plaques decreased more quickly than expected with dilution of the inoculant) (

segments 1–5 (passage 1) and segments 1–4 (passage 2)

we suggest that RABV hijacks a specific mechanism that enables the neuron to transport cargos over long distances.

Rabies virus (RABV) is a neurotropic virus that depends on long distance axonal transport in order to reach the central nervous system (CNS).

Measuring both the area and average intensities of the RABV particles in each group, we found that the p75NTR positive RABV particles were larger in size, (average area of 1.34±0.09 µm2 vs. 0.81±0.07 µm2, p<0.0005), and had stronger intensity of GFP signal, when normalized to the average intensity of RABV particles in each experiment (1.24±0.11 vs. 0.61±0.1, p<0.001) (Fig. 8K–L).

ence there are likely to be additional ways for RABV to merge into the p75NTR-RABV endosome

Other membrane-associated components have also been implicated in RABV binding [20]. By binding one of its receptors, RABV could enter the cell and activate downstream signaling which would allow it to hijack and manipulate axonal transport machineries. Although p75NTR is known to be involved in the retrograde transport of neurotrophic factors, little is known regarding its direct contribution to viral transport.

Possibly, RABV binding to dynein tethers projecting microtubules (MT) in the cell cortex thereby facilitating its retrograde trafficking from the cell periphery. Following this tethering, RABV particles can merge into the RABV-p75NTR endosomes and travel to the neuron cell body.

Such reverse transcription

Dr. June knew that a drug could lower IL-6

tocilizumab

the altered T-cells persist in the bloodstream

The researchers are not entirely sure why the treatment works, or why it sometimes fails.

It is not clear whether a patient’s body needs the altered T-cells forever. The cells do have a drawback: they destroy healthy B-cells as well as cancerous ones, leaving patients vulnerable to certain types of infections, so Emma and the other patients need regular treatments with immune globulins to prevent illness.

Within hours

According to a study published in Nature in February 2009, the system can detect outbreaks nearly two weeks before they show up in the official CDC reports.

won’t know until the end of the season.”

Other members of the A3 family are believed to affect other exogenous viruses as well as endogenous retrovirus/retroelement movement within the genome. In particular, human A3A is a potent inhibitor of IAP and MusD and other retrotransposons such as LINE-1 and this inhibition is CDA-independent, at least in cultured cells [18]–[20]. A3A also inhibits adeno-associated virus replication, a nuclear-replicating parvovirus, via CDA-independent means [20]. In monocytes, A3A restricts HIV-1 infection and the decrease in A3A levels that occurs during monocyte-to-macrophage development is concomitant with increased susceptibility to HIV-1 infection [21]. A3A is not packaged into HIV virions and is thought to restrict infection by targeting incoming virus [22]–[24]. In contrast, A3A is packaged in human T-lymphotropic virus type-I virions and restricts infection, at least in transfected cells [25]. A3A preferentially deaminates cytidines that are in a TC motif [26].

To determine the level of transgene expression, we first isolated RNA from different tissues, including peripheral blood mononuclear cells (PBMCs), and performed reverse-transcribed real-time quantitative PCR (RT-qPCR). RNA from human H9 cultured cells and human and C57BL/6 mouse PBMCs served as controls. For each transgene, there was one high- (A3Ghigh, A3Ahigh) and one low- (A3Glow, A3Alow) expressing strain, defined by their relative expression in lymphoid tissues. The A3Ghigh strain expressed higher levels of the transgene than the endogenous mouse gene in spleen and thymus, but similar A3G levels in mouse and human PBMCs, while the A3Glow strain expressed approximately 10-fold lower levels in these tissues (Figure 1A). In contrast, the A3Ahigh strain expressed similar or lower levels than mouse A3; there was also about 2-fold lower expression of A3A in mouse PBMCs than in human PBMCs (Figure 1B). The A3Alow strain had very low but detectable levels of expression in several tissues. Since the β-actin regulatory region was used, transgene expression was seen in many tissues and in several at levels higher than endogenous mouse A3 (e.g. heart, brain and liver) (Figure 1A and 1B). We also performed western blots on different tissues from the 4 different mouse strains, using antiserum that detects both A3A and A3G. The relative protein expression levels were similar to that seen at the RNA level (Figure S1A and S1B).

We next determined if the in vivo-produced A3A and A3G proteins were functionally active. Extracts were prepared from primary splenocyte cultures and equal amounts (total protein concentration/volume) were incubated with FAM-labeled substrates containing the A3A- or A3G-preferred target sequence (S50-TTC and S50-CCC, respectively). As controls, we also performed these assays with extracts prepared from 293T cell lines transfected with A3A or A3G. Activity could be readily detected in transgenic mice expressing high levels of A3A or A3G. Further, in accord with the known specificity of the cytidine deaminases, extracts from the A3Ahigh mice deaminated the TTC- more efficiently than CCC-containing substrates, while those from A3Ghigh mice more efficiently deaminated the CCC substrate (Figure 2). For both A3Alow and A3G low, trace amounts of activity were detectable with the preferred substrates, while no activity was detectable with either endogenous mA3 or from mA3 knockout splenocytes. No deaminase activity was detected with WT mouse extracts, perhaps because the mouse protein has lower overall activity or expression. These data show that the transgenic mice expressed catalytically active human deaminases in these heterologous cells.

Humans have 7 APOBEC3 genes and determining how each specifically functions to inhibit retroviruses like HIV is complicated, because all 7 can be produced in a given cell type or tissue.

To overcome this limitation, we made transgenic mice that express two of the human proteins, APOBEC3A and APOBEC3G in mice that do not express their own APOBEC3. These mice were able to effectively block infection by several mouse retroviruses

We were unable to perform similar assays with in vivo produced MMTV, because the only cell-free virus in mice is found in milk and mammary tumors and we have not yet established breeding colonies of virus-infected human A3 transgenic mice.

A3G and A3A inhibit retrovirus infection by different means.

Two A3A and A3G mouse strains each were generated, expressing levels of these proteins within the range or at levels lower than that seen in human cells. This likely has relevance to what occurs in individual humans, where non-coding region polymorphisms in A3 genes alter expression levels and may influence progression to HIV-induced disease

An additional limitation of previous studies done on human A3 proteins is the reliance on transfecting constructs expressing A3 proteins, which may not reflect the endogenous levels of a protein expression found in vivo