An important breakthrough has been made in the research of anti-SARS medicine in south China's Guangdong Province. About 20,000 ml. of horse serum comprising an idiosyncratic SARS neutralization antibody were successfully extracted on July 20, according to relative departments in Guangdong Province.
The curative effect of the horse serum is 100 times the serum from convalescent SARS patients. Relative experts said the horse serum will be gradually applied on animal and human experiments after being purified and refined. If everything goes well, it will be used in clinical treatment next February.
Medical departments in Guangdong advocated that people donated their blood in order to save severe SARS patients, after serum from convalescent SARS patients had been proved to contain neutralization antibodies which could directly kill the SARS virus. Medical workers in No. 8 People's Hospital of Guangzhou, the No.3 Hospital attached to Sun Yat-sen University who had contracted SARS took the lead in donating blood, which had successfully saved many patients in Beijing, Changchun and Guangzhou. Although the serum from convalescent SARS patients had special curative effect on the SARS virus, its resources were very limited and blood recipients may have the risk of contracting other diseases which are spread through blood, such as Hepatitis B, Hepatitis C and AIDS.
Curative effect of horse serum is 100 times of human serum
The Inactivated Vaccine Subject Team on SARS of Guangdong spent three months on the research. They successively neutralized and then killed the SARS virus from SARS patients five times since May 20 and then injected it into nine horses from Changchun and Guangdong. The neutralization antibody of the SARS virus had been developed in these horses. Its titer reached 5,120, 100 times the titer of the serum from convalescent SARS patients, that is to say, the curative effect of the extracted 20,000 ml. horse serum was equal to 2 million ml human serum. If 100 ml. human serum can save one SARS patient, then the currently developed horse serum can save 20,000 SARS patients.
Three steps for the application of horse serum
Led by Sun Yat-sen University, the Inactivate Vaccine Subject Team was composed of the Military Necessity University of PLA (People's Liberation Army), NO.1 Military Hospital of PLA, the Biological Medicine Research Base of Jinan University and Guangdong Provincial Center for Disease Control and Prevention.
The subject team will first purify and refine this batch of horse serum. Direct injection of the horse serum into the human body will cause an allergy and repellent effect. If splitting the SARS antibody in the horse serum with papain and pepsin and cutting the "allergic part" and saving the "effective part", patients will not be allergic to it. The whole procedure will need 10 days.
The second step, to conduct analysis and appraisal on the curative effect of the horse serum, which can be confirmed through two channels: one to inject the horse serum into animals, such as monkeys, and then infect the animal with the SARS virus; second, to treat SARS infected animals with the horse serum. The results on the neutralization reaction of the cells level carried out in the lab had approved that under the microscope, the number of cells in the cultivation solution of kidney cells from the African green monkey which was attacked by the SARS virus, was reducing, deforming, destroyed, dissolving and even totally dead. If adding the horse serum first and then attacking it with SARS virus later, the shape of kidney cells are the same as normal cells. Doctor Lu Jiahai disclosed that this step could be achieved within a month if qualified animal models were available.
Finally, the horse serum will be applied on a human test. After appraisal of its curative effect and safety, it will be widely used as emergent injections on medical workers who may have contracted SARS or suspicious cases as well as treatment on confirmed SARS patients.
Opposite voice
Wang Jingxing, expert from the Anti-SARS Task Team of the Ministry of Science and Technology and vice director of China's Blood Transfusion Association, said the horse serum was extracted from the horse whose protein structure was different from the human body. It is very likely to cause repellent and allergic reaction if it is used in the treatment of humans, and it may endanger people's life. For clinical diseases, the horse serum is only adopted in emergency.
Wang said that his subject team has made research on this before and the effect was not so satisfactory. He also showed his doubts on the saying that "the curative effect of horse serum is 100 times of human serum". According to Wang, the calculation method and result made in lab are not totally identical to the clinical practice. Therefore, it is too early to make such a conclusion.
(China.org.cn by Wang Qian July 28, 2003)
