New adenovirus-based vaccine vectors targeting Pfs25 elicit antibodies that inhibit Plasmodium falciparum transmission

An effective malaria transmission-blocking vaccine (TBV) would be a major advance in the current efforts to eliminate and, ultimately, eradicate malaria. Antibodies against Plasmodium falciparum surface protein, ...
Source: Malaria Journal - Category: Infectious Diseases Authors: Source Type: research

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The cleverest of enemies thrive on surprise attacks. Viruses—and coronaviruses in particular—know this well. Remaining hidden in animal hosts for decades, they mutate steadily, sometimes serendipitously morphing into more effective and efficient infectious agents. When a strain with just the right combination of genetic codes that spell trouble for people makes the leap from animal to human, the ambush begins. Such was the case with SARS-CoV-2, the coronavirus behind COVID-19, and the attack was mostly silent and insidious at first. Many people infected with SARS-CoV-2 remained oblivious as they served as the v...
Source: TIME: Health - Category: Consumer Health News Authors: Tags: Uncategorized COVID-19 Magazine Source Type: news
The blockade of programmed cell death-1 (PD1) and its ligand PDL1 has been proven to be a successful immunotherapy against several cancers. Similar to cancer, PD1 contributes to the establishment of several chronic infectious diseases, including malaria. While monoclonal antibodies (mAbs) targeting checkpoint receptors are revolutionary in cancer treatment, the immune-related adverse events (irAEs) may prevent their utilization in prophylactic and therapeutic treatments of infectious diseases. The irAEs are, in part, due to the prolonged half-life of mAbs resulting in prolonged activation of the immune system. As an altern...
Source: Frontiers in Immunology - Category: Allergy & Immunology Source Type: research
In this study, we investigated combining two liver-stage antigens, P. falciparum LSA1 (PfLSA1) and PfLSAP2, and investigated the induction of protective efficacy by coadministration of single-antigen vectors or vaccination with dual-antigen vectors, using simian adenovirus and modified vaccinia virus Ankara vectors. The efficacy of these vaccines was assessed in mouse malaria challenge models using chimeric P. berghei parasites expressing the relevant P. falciparum antigens and challenging mice at the peak of the T cell response. Vaccination with a combination of the single-antigen vectors expressing PfLSA1 or PfLSAP2 was ...
Source: Infection and Immunity - Category: Infectious Diseases Authors: Tags: Microbial Immunity and Vaccines Source Type: research
Malaria parasites undergo several stages in their complex lifecycle. To achieve reductions in both the individual disease burden and malaria transmission within communities, a multi-stage malaria vaccine with high effectiveness and durability is a more efficacious strategy compared with a single-stage vaccine. Here, we generated viral-vectored vaccines based on human adenovirus type 5 (AdHu5) and adeno-associated virus serotype 1 (AAV1) expressing a fusion protein of the pre-erythrocytic stage Plasmodium falciparum circumsporozoite protein (PfCSP) and the transmission-blocking sexual stage P25 protein (Pfs25). A two-dose h...
Source: Frontiers in Immunology - Category: Allergy & Immunology Source Type: research
Yenni Yusuf, Tatsuya Yoshii, Mitsuhiro Iyori, Kunitaka Yoshida, Hiroaki Mizukami, Shinya Fukumoto, Daisuke S. Yamamoto, Asrar Alam, Talha Bin Emran, Fitri Amelia, Ashekul Islam, Hiromu Otsuka, Eizo Takashima, Takafumi Tsuboi, Shigeto Yoshida
Source: Frontiers in Immunology - Category: Allergy & Immunology Source Type: research
We describe an alternative "prime and target" vaccination strategy aimed specifically at inducing high numbers of tissue-resident memory T cells present in the liver at the time of hepatic infection. This approach bypasses the need for very high numbers of circulating T cells and markedly increases the efficacy of subunit immunization against liver-stage malaria with clinically relevant Ags and clinically tested viral vectors in murine challenge models. Translation to clinical use has begun, with encouraging results from a pilot safety and feasibility trial of intravenous chimpanzee adenovirus vaccination in huma...
Source: Science Translational Medicine - Category: Biomedical Science Authors: Tags: Research Articles Source Type: research
We examined immunity elicited by these vaccines in the context of two adjuvants approved for human use (AddaVax and Matrix-M). Matrix-M supported the highest anti-PvCSP antibody titers when combined with Rv21, and, interestingly, mixing PvCSP Rv21 and PvTRAP viral vectors enhanced immunity to malaria over levels provided by single vaccines.
Source: Infection and Immunity - Category: Infectious Diseases Authors: Tags: Microbial Immunity and Vaccines Source Type: research
LITFL • Life in the Fast Lane Medical Blog LITFL • Life in the Fast Lane Medical Blog - Emergency medicine and critical care medical education blog aka Tropical Travel Trouble 010 Peer Reviewer: Dr Jennifer Ho, ID physician QLD, Australia You are an ED doc working in Perth over schoolies week. An 18 yo man comes into ED complaining of fever, rash a “cracking headache” and body aches. He has just hopped off the plane from Bali where he spent the last 2 weeks partying, boozing and running amok. He got bitten by “loads” of mosquitoes because he forgot to take insect repellent. On e...
Source: Life in the Fast Lane - Category: Emergency Medicine Authors: Tags: Clinical Cases Tropical Medicine arthralgia dengue fever rash Source Type: blogs
LITFL • Life in the Fast Lane Medical Blog LITFL • Life in the Fast Lane Medical Blog - Emergency medicine and critical care medical education blog aka Tropical Travel Trouble 009 The diagnosis of HIV is no longer fatal and the term AIDS is becoming less frequent. In many countries, people with HIV are living longer than those with diabetes. This post will hopefully teach the basics of a complex disease and demystify some of the potential diseases you need to consider in those who are severely immunosuppressed. While trying to be comprehensive this post can not be exhaustive (as you can imagine any patient with ...
Source: Life in the Fast Lane - Category: Emergency Medicine Authors: Tags: Clinical Cases Tropical Medicine AIDS art cryptococcoma cryptococcus HIV HIV1 HIV2 PEP PrEP TB toxoplasma tuberculoma Source Type: blogs
Abstract Adenovirus (Ad) is thought to be one of the most promising platforms for a malaria vaccine targeted against its liver stages, because of its ability to induce a strong T-cell response against a transgene. However, a further improvement of this platform is needed in order to elicit another arm of the immunity, i.e. humoral response, against malaria. In order to augment immunogenicity and protective efficacy of Ad-based malaria vaccine, we inserted B-cell, as well as CD4+ T-cell, epitopes of Plasmodium falciparum circumsporozoite protein (PfCSP) into the capsid protein, Hexon, and the core protein, VII (pVI...
Source: Vaccine - Category: Allergy & Immunology Authors: Tags: Vaccine Source Type: research
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