Horse antibodies 'protect against bird flu'

[Mellie]

http://news.viewlondon.co.uk/Horse_antibodies_protect_against_bird_flu_17079736.html

Horse antibodies 'protect against bird flu'




Antibodies derived from horses could help protect against avian flu, new research has found.

Scientists in China found that by injecting horse antibodies into mice infected with the H5N1 strain, it stopped the animals dying from the virus.

Jiahai Lu from Sun Yat-Sen University in Guangzhou, China, along with colleagues from other institutions conducted a series of experiments published today in the Respiratory Research journal.

Just 100 micrograms of the horse antibody ensured a total survival rate for the mice in the trial, compared to the control group where all died from the virus.

The H5N1 strain of avian flu was first seen in Asia and has since spread around Europe and Africa and has already killed poultry workers in Turkey and other countries.

Though it is yet to kill humans in great numbers, there are concerns that it could mimic earlier outbreaks of bird flu and cross to humans, leading to the current research into protection against it.

Health organisations around the world are preparing for a possible outbreak of theH5N1, with the UK licensing oseltamivir as an inhibitor of the disease, but this latest study is the first to suggest a form of total protection against the virus.

Researchers hope that the new breakthrough will offer early treatment of H5N1 in humans if it ever does cross the species barrier in large numbers.

 

[Snowy Owl]

Avian flu vaccine seen in Equine antibodies

Avian flu vaccine seen in Equine antibodies

Avian flu vaccine seen in Equine antibodies
http://bird-flu.health-library.info/site/articles-436/#more-436

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Passive immunotherapy — using antibodies from horses — might be a way to treat highly pathogenic avian influenza in humans, researchers here reported.
In a pilot study, purified antibodies to the H5N1 strain of avian influenza, derived from horses, proved able to prevent infected mice from dying, according to Jiahai Lu, Ph.D., of the school […]


Passive immunotherapy — using antibodies from horses — might be a way to treat highly pathogenic avian influenza in humans, researchers here reported.


In a pilot study, purified antibodies to the H5N1 strain of avian influenza, derived from horses, proved able to prevent infected mice from dying, according to Jiahai Lu, Ph.D., of the school of public health at Sun Yat-sen University.


Although vaccines against the virus are under development, using various strategies, no vaccine has emerged as a front-runner, Dr. Lu and colleagues noted in the March online issue of Respiratory Research. Also, there are few drugs that can be used to treat H5N1 infection.
In the absence of a vaccine or good treatments, they said, passive immunotherapy, using antibodies derived from other animals, “may be an alternative strategy.”


The researchers reported two experiments, both using highly purified fragment antigen binding (FAB) molecules derived from equine antibodies to the H5N1 hemagglutinin glycoprotein.


In the first, they showed that the equine antibodies prevented the infection of dog kidney cells (from the established MDCK cell line).
Specifically, control cells were exposed to a level of H5N1 virus that caused half of them to display a cytopathic effect, at the same level. Cells treated with the antibodies were unaffected.


In the second experiment, the researchers showed that the equine antibodies prevented death from H5N1 flu in infected BALB/c mice, which are known to be susceptible to the H5N1 flu. The mice were randomized to four groups of 10 and infected intranasally with 50 microliters of H5N1 virus.


A day later, three groups of mice were injected intraperitoneally with 50, 100, or 200 mcg of the antibody preparation. The fourth group, used as controls, received 200 mcg of normal horse sera.


The H5N1 infection was fatal to all the control mice, but seven of the 10 mice given 50 mcg of the antibody preparation survived, as did all of the mice at the higher dosages, Dr. Lu and colleagues reported.


“Until we have an efficacious vaccine, specific anti-H5N1 agents, and effective epidemiologic control measures for H5N1 virus infection, highly pathogenic H5N1 virus is likely to be a major health threat to the world,” Dr. Lu an colleagues concluded.


In that context, they said, H5N1-specific passive immunotherapy “may potentially be used for the early treatment of avian influenza patients to reduce the severity of illness and the likelihood of H5N1 transmission to others.”


The researchers noted that one drawback to the procedure may be that polyclonal antibodies derived from horses have the potential to cause a strong host immune response (i.e., serum sickness), which might inhibit its use in the clinic; careful purification can reduce that risk, they said.


The H5N1 strain, now on the rampage in bird populations in Asia, Africa, and Europe, occasionally infects humans although it is not easily transmitted between people. Yet health authorities worry that the virus has the potential to become a human pandemic disease with only small genetic changes.


As of March 24, the World Health Organization confirmed 186 cases of human infection with the H5N1 strain, of which 105 have proved fatal; China has reported 16 cases, 11 of them fatal.


The Chinese report on equine antibodies came as researchers at the Johns Hopkins Bloomberg School of Public Health were turning the spotlight on Burma, where they said the military dictatorship there is allowing several infectious diseases — including AIDS, drug-resistant tuberculosis, malaria, and H5N1avian flu — to spread unchecked.


Because of the regime’s repressive policies, “there is a fear that if a human form of H5N1 were to take hold in Burma, it could potentially spread unchecked for weeks or months before anyone knew about it,” said Chris Beyrer, M.D., director of the Bloomberg School’s Center for Public Health and human rights.

 

[Niko]

Re: Horse antibodies 'protect against bird flu'

FT member, runninghorses, brought this study up. Does anyone know if this ever got out of the trial stage? Personally, I don't like the idea of horses being infected, but that is irrelevant, I suppose.

Horse anti-serum effectively protects H5N1 infected mice
Medical Studies/Trials
Published: Tuesday, 28-Mar-2006


Antibodies against the bird flu virus H5N1, derived from horses, prevent mice infected with H5N1 from dying from the virus.

A study published in the open access journal Respiratory Research reveals that a dose of 100 microgram of horse anti-serum effectively protects infected mice.

These results suggest that anti-H5N1 antibodies developed in horses could potentially be used to prevent death from H5N1 influenza, or as early treatment for the disease, in humans.

Jiahai Lu from Sun Yat-Sen University in Guangzhou, China and colleagues from other institutions in China infected dog kidney cells in vitro with a lethal dose of H5N1 and simultaneously exposed the cells to horse antibodies against H5N1. Lu et al.'s results show that horse antibodies to H5N1 protected cells against H5N1 in vitro - the cells simultaneously infected with H5N1 and exposed to horse antibodies did not die.

Lu et al. then injected horse antibodies into 40 mice that had been infected with a lethal dose of H5N1 24 hours earlier. The authors also injected horse serum without H5N1 antibodies into a group of mice that acted as controls.

The authors found that 50 microgram of antibody protected 70% of the mice against death by H5N1 and 100 microgram of antibody protected 100% of the mice. The mice in the control group died nine hours after receiving the normal horse serum.

http://respiratory-research.com

 

[Niko]

Re: Horse antibodies 'protect against bird flu'

ABSTRACT

Passive immunotherapy for influenza A H5N1 virus infection with equine hyperimmune globulin F(ab')2 in mice
Jiahai Lu* 1 , Zhongmin Guo* 1 , Xinghua Pan* 2 , Guoling Wang* 1 , Dingmei Zhang* 1 , Yanbin Li* 3 , Bingyan Tan1 , Liping Ouyang1 and Xinbing Yu1
1Sun Yat-sen University, Guangzhou 510080, China
2Kunming General Hospital of Chengdu Military Area, Kunming, 650000, China
3Haerbin Veterinary research institute, Haerbin, 150000, China

Respiratory Research 2006, 7:43 doi:10.1186/1465-9921-7-43

Published 23 March 2006

Abstract

Background

Avian influenza virus H5N1 has demonstrated considerable pandemic potential. Currently, no effective vaccines for H5N1 infection are available, so passive immunotherapy may be an alternative strategy. To investigate the possible therapeutic effect of antibody against highly pathogenic H5N1 virus on a mammal host, we prepared specific equine anti-H5N1 IgGs from horses vaccinated with inactivated H5N1 virus, and then obtained the F(ab')2 fragments by pepsin digestion of IgGs.

Methods

The horses were vaccinated with inactivated H5N1 vaccine to prepare anti-H5N1 IgGs. The F(ab')2 fragments were purified from anti-H5N1 hyperimmune sera by a protocol for 'enhanced pepsin digestion'. The protective effect of the F(ab')2 fragments against H5N1 virus infection was determined in cultured MDCK cells by cytopathic effect (CPE) assay and in a BALB/c mouse model by survival rate assay.

Results

By the protocol for 'enhanced pepsin digestion', total 16 g F(ab')2 fragments were finally obtained from one liter equine antisera with the purity of over 90%. The H5N1-specific F(ab')2 fragments had a HI titer of 1:1024, and the neutralization titre of F(ab')2 reached 1: 2048. The in vivo assay showed that 100 μg of the F(ab')2 fragments could protect BALB/c mice infected with a lethal dose of influenza H5N1 virus.

Conclusion

The availability of highly purified H5N1-specific F(ab')2 fragments may be promising for treatment of influenza H5N1 infection. Our work has provided experimental support for the application of the therapeutic equine immunoglobulin in future large primate or human trials.

http://respiratory-research.com/content/7/1/43/abstract