'Mosquito smoothie' innovation boosts future malaria vaccine potential

‘Mosquito smoothie’ innovation boosts future malaria vaccine potential

  • June 17, 2021

A faster method for collecting pure malaria parasites from infected mosquitos could accelerate the development of new, more potent malaria vaccines.

The new method, developed by a team of researchers led by Imperial College London, enables more parasites to be isolated rapidly with fewer contaminants, which could simultaneously increase both the scalability and efficacy of malaria vaccines.

The parasite that causes malaria is becoming increasingly resistant to antimalarial drugs, with the mosquitoes that transmit the disease also increasingly resistant to pesticides. This has created an urgent need for new ways to fight malaria, which is the world’s third-most deadly disease in under-fives, with a child dying from malaria every two minutes.

Existing malaria vaccines that use whole parasites provide moderate protection against the disease. In these vaccines, the parasites are ‘attenuated’ – just like some flu vaccines and the MMR vaccine – so they infect people and raise a strong immune response that protects against malaria, but don’t cause disease themselves.

However, these vaccines require several doses, with each dose requiring potentially tens of thousands of parasites at an early stage of their development, known as sporozoites. Sporozoites are normally found in the salivary glands of mosquitoes, and in a natural infection are passed to humans when the mosquito bites. They then travel to the human liver, where they prepare to cause infection in the body.

Extracting sporozoites for use in a live vaccine currently requires manual dissection of the mosquito salivary glands – miniscule structures behind the mosquito head – by a skilled technician, which is a time-consuming and costly process.

The new method, described today in Life Science Alliance, vastly speeds up this process by effectively creating a ‘mosquito smoothie’ and then filtering the resulting liquid by size, density and electrical charge, leaving a pure sporozoite product suitable for vaccination. Importantly, no dissection is required.

Lead researcher Professor Jake Baum, from the Department of Life Sciences at Imperial, said: “Creating whole-parasites vaccines in large enough volumes and in a timely and cost-effective way has been a major roadblock for advancing malaria vaccinology, unless you can employ an army of skilled mosquito dissectors. Our new method presents a way to radically cheapen, speed up and improve vaccine production.”

But it’s not just about speed and cost. Traditional dissection methods struggle to remove all contaminants, such as proteins from the salivary glands, which are often extracted with sporozoites. The extra debris is likely to affect the infectivity of the sporozoites once they are inside the body, and could even affect how the immune system responds, impacting the efficacy of any whole parasite vaccine.

The new method also tackles this problem, resulting in pure uncontaminated sporozoite samples. The team discovered that, as well as being purer, sporozoites produced were surprisingly more infectious, hinting that vaccines produced using their method may require a much lower dose of sporozoites.

First author of the study Dr Joshua Blight, from the Department of Life Sciences at Imperial, said: “With this new approach we not only improve the scalability of vaccine production, but our isolated sporozoites may actually prove to be more potent as a vaccine, giving us additional bang per mosquito buck.”

The team developed and tested their method with both human and rodent malaria parasites. They then tested the rodent version as a vaccine in mice, and found that when exposed to an infected mosquito bite, vaccinated mice showed 60-70 per cent protection when immunisations were given into muscle. When the same sporozoites were given directly into the blood stream (intravenously) protection was 100 per cent, known as ‘sterile’ protection.

The researchers are now developing the method further in readiness for mass manufacture of sporozoites under good manufacturing practice (GMP) conditions in order to produce a vaccine ready for human challenge trials. The plan is that participants would be given vaccine-grade sporozoites produced using this method and then purposefully bitten by an infected mosquito.

Looking beyond vaccines the researchers also say their method should help accelerate studies of sporozoite biology in general, which could in turn lead to fresh insights into the liver stage of malaria and new drug and vaccine regimes.

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The research was funded by the Wellcome Trust and the Bill & Melinda Gates Foundation.

Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.

Florida News Times

Third dose of COVID vaccine may boost immunity of transplant recipients-WUSF public media

  • June 16, 2021

Pharmacist Katie McDonough reconfigures the Pfizer-BioNTech vaccine when filling syringes at the UMass Memorial Healthcare COVID-19 Vaccination Center at the Mercantir Center in Worcester on April 22, 2021. Joseph Prezioso AFP

A small new study offers a faint hope that organ transplant recipients can be given a third dose of the COVID-19 vaccine to enhance their defense against coronavirus.

It’s important Previous studies show Almost half of organ transplant recipients showed no antibody response after two doses of Pfizer or modelna vaccine.

And even transplant recipients who responded antibody to vaccination were often more modest than those with a healthy immune system. Therefore, doctors advise these patients not to assume that vaccination is equivalent to immunity. According to the Scientific Registry of Transplant Recipients, more than 400,000 people in the United States have undergone organ transplants.

In a new study Published this week Annual report of internal medicineResearchers at Johns Hopkins University of Medicine tracked 30 organ transplant recipients who received a third dose of the COVID-19 vaccine.

They found that one-third of patients who did not have previously detectable antibodies showed increased antibody levels after the third dose. And all patients who previously showed low levels of antibody after two doses of vaccine showed high levels of antibody after the third dose.

“For everyone involved [these are] A promising finding that the defensive immunity of immunosuppressed people may ultimately be reached, “said Dr. Dolly Segev, a transplant surgeon and study author at Johns Hopkins Medicine... Although the findings are preliminary, he says, they are consistent with previous studies of how transplant recipients respond to other vaccines.

Researchers say this is the first study to report a response to a third vaccination. In this observational study, they tracked group transplant recipients who asked for a third dose on their own and tested antibody levels after dosing.

Researchers say their findings support the use of clinical trials to determine whether transplant recipients should receive the COVID-19 vaccine booster as part of standard clinical care. If the findings are reproduced in a larger study, they may affect some other types of immunocompromised patients.In fact, in France Health officials already recommend Patients with severe immunodeficiency, such as organ transplant patients and dialysis patients, receive a third dose of Pfizer or modelna vaccine.

Segev says he expects more data from France to come from France regarding the effectiveness of a third dose in immunocompromised patients.

“Obviously, all we need to learn is … who responds to the third dose,” he says. “People who need changes other than the third dose,” such as temporary changes in immunosuppressive drugs to improve the antibody response to vaccination.

Segev and his colleagues are currently seeking regulatory approval to give transplant recipients a third dose of the vaccine and initiate an intervention study that can monitor their response. They hope to be able to register participants next month or two months.

But for now, “the best we can all do for immunosuppressed people is that our normal immune system can protect vulnerable friends and family among us who have suppressed the immune system. So, get all the vaccinations, “he says.

Third dose of COVID vaccine may boost immunity of transplant recipients-WUSF public media

Source link Third dose of COVID vaccine may boost immunity of transplant recipients-WUSF public media

Covid immunity lasts for a year, vaccine boost helps fight variants, study says

Covid immunity lasts for a year, vaccine boost helps fight variants, study says

  • June 16, 2021
Covid-19 vaccine shot | Representational image | Bloomberg


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New Delhi: Immunity in Covid-recovered patients is long-lasting and gets a 50-fold boost after vaccination, according to a new study.

The study, published in the journal Nature Monday, also said that the mRNA vaccines can sufficiently protect against emerging mutations.

More than a year after the Covid-19 pandemic broke, the emergence of new variants that appear to be more transmissible and resistant to antibodies has added to the challenge of controlling the spread of the disease.

To understand how long the immunity lasts, researchers from the Rockefeller University, Weill Cornell Medicine and California Institute of Technology assessed the blood samples of 63 people who had recovered from Covid-19. The samples were collected 1.3, 6.2 and 12 months after infection.

Of these 63 people, 41 per cent had received mRNA vaccines.

The study found that in Covid-recovered patients, antibodies against the protein known as receptor binding domain (RBD) of SARS-CoV-2 and neutralising activity remain relatively stable from six to 12 months, without vaccination.

A receptor-binding domain is a key part of the virus located on its ‘spike’ protein that allows it to latch onto the cell to gain entry into cells and lead to infection.

Memory B cells — a type of white blood cells that learn to recognise specific viral proteins — was also found to remain stable upto 12 months.


Also read: New atomic-scale 3D map of Covid virus protein could hold clue to preventing lung damage


Antibody levels

In addition, the team found that vaccination increases all components of the antibody response. Antibody levels remained relatively unchanged between six to 12 months after SARS-CoV-2 infection, and that vaccination further boosted this activity by nearly 50-fold.

The study found that the ability of vaccine-induced antibodies to neutralise variants of concern was comparable to or greater than that against the original virus.

Researchers also identified that the broad response against the SARS-CoV-2 virus involves what is known as the antibody somatic mutation — a cellular mechanism using which the body’s immune system adapts to the changing virus during the course of the infection.

This results in antibodies that are exceptionally resistant to mutations in the SARS-CoV-2 RBD — including those found in variants of concern

In addition, B cells that produce a broad range of potent antibodies are retained in the body over time and expand dramatically after vaccination.

The data suggest that immunity in Covid-recovered individuals will be very long-lasting, researchers said. Along with this, Covid-recovered patients who receive mRNA vaccines produce antibodies and memory B cells that should be protective against circulating SARS-CoV-2 variants, the study concluded.

(Edited by Neha Mahajan)


Also read: AY.1 — The new Covid variant on world radar stems from Delta variant, linked to immune escape


 

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