Good news for recovered patients: To stop the new coronavirus, scientists have found that our immune system has many ways.

▎ editor of YaoMing Kant content team ▎ so far, in the face of the covid-19 pandemic, we have no specific drugs or vaccines to prevent the new coronavirus.with regard to the ongoing vaccine development, there are also concerns about whether the immune system can produce a substantial and lasting response to the cunning new coronavirus.in two research papers recently published in the top academic journals Science and cell, scientists have found a variety of neutralizing antibodies specific to new coronavirus and strong anti-virus immune response in the immune system of convalescent patients.the researchers pointed out that these findings could contribute to the development of better vaccines, "indicating the development of long-term protective immunity".a research team composed of several Chinese research institutions has officially published research papers on neutralizing antibodies in science.the main persons in charge of this study include Professor Wu Yan of Capital Medical University, academician Gao Fu, director of CDC, Gao Feng researcher of Tianjin Institute of industrial biotechnology, Chinese Academy of Sciences, and Liu Lei, President of Shenzhen Third People's hospital.at the beginning of Xinguan epidemic, medical personnel used plasma therapy to separate plasma from convalescent patients, and then transfused them to severe or critical patients.antibodies in plasma, especially neutralizing antibodies with high titer, can play an antiviral role."however, there are some risks in plasma therapy. It is more stable and reliable to use high purity monoclonal antibody with neutralizing activity as drug."pointed out by Professor Wu Yan.Image Source: Yao Ming Kant content team mapping. To this end, the research team first picked out virus specific memory B cells from a patient's convalescent serum, which are mainly responsible for the production of antibodies.because the new coronavirus binds to ACE2 receptor on cell surface through RBD region of S protein, it starts infection.therefore, the researchers used the RBD protein of the new coronavirus as a "bait" to screen neutralizing antibodies binding to it.the four monoclonal antibodies (B5, b38, H2 and H4) not only had binding activity with RBD of new coronavirus, but also showed strong specificity and did not bind to RBD of SARS virus.previous studies have found that although there are many similarities between new coronavirus and SARS virus, only a few key amino acid differences make the RBD of new coronavirus have stronger binding force with receptor.further analysis showed that two of the antibodies (b38 and H4) could compete with ACE2 receptor completely."this is equivalent to" occupying "the binding site of RBD and ACE2, and the virus can no longer bind to ACE2. "explained Professor Wu Yan. moreover, the two antibodies recognize different parts of RBD of new coronavirus, and they may be able to "work together" to exert stronger neutralization activity. } to explore the neutralization effect of b38 and H4 McAbs on new coronavirus (photo source: reference [1]). The results of animal experiments preliminarily showed the protective effect of these two McAbs. the researchers genetically engineered mice to express human ACE2 and then injected them with a single dose of monoclonal antibody (25 mg / kg) 12 hours after challenge. compared with the control group, b38 or H4 could significantly reduce the viral RNA copies in lung tissue of mice. moreover, b38 also shortened the course of disease, and recovered in just three days. based on these results, the authors suggest that the identified neutralizing antibody is expected to be a candidate drug for the treatment of new coronavirus, and the "antibody cocktail" mixed with the two McAbs has the potential to be called an alternative treatment strategy to avoid the potential escape mutation of the virus. } This research paper was published online in the form of "advance publication" (screenshot: cell official website). In another study published in cell, scientists from La Jolla Institute of immunology in the United States analyzed the T cell response of a group of rehabilitation patients in detail. compared with B cells, T cells can prevent infection in two different ways: helper T cells, which help to stimulate immune defenders such as B cells to play a role, while killing T cells can find and destroy infected cells. the team tested 20 patients who recovered from mild illness after infection with the new coronavirus, and found that all the people had helper T cells that recognized the S protein of the new coronavirus, and in 70% of the subjects, specific killing t cells against the new coronavirus were detected. this means that "the immune system recognizes the new coronavirus and initiates an effective immune response. "said Professor Alessandro Sette, one of the research leaders. } in patients with covid19, T cells respond to a variety of proteins of the new coronavirus (image source: reference [3]) "if we only see a small amount of immune response, we should be worried, but what we see is a very strong T cell response to S protein. "added Professor Sette. this result is undoubtedly good news for vaccines developed mainly for S protein. in addition, the researchers also found that T cells responded to various other proteins of the new coronavirus, which provided more clues for vaccine development. more interestingly, the team also analyzed individuals who were not infected with the new coronavirus and tested T cell responses from dozens of blood samples collected from 2015 to 2018. they found that although these people had never been exposed to the new coronavirus, helper T cells were also detected in 40% to 60% of blood samples. } other coronaviruses may also provide immunity to individuals who have not been exposed to the new coronavirus (photo source: reference [3]). According to the analysis of the researchers, this cross reaction shows that the proteins of several coronaviruses causing "common cold" in the past are similar to those of the new coronavirus, and there may be a small amount of residual immunity. this study has attracted the attention of many virologists and immunologists. although these results do not prove that patients with cross reaction or rehabilitation will definitely be free from reinfection in the future, the identification of T cells that specifically respond well to the new coronavirus is "encouraging news. "Dr. Angela Rasmussen, a virologist at Columbia University, said," it predicts the development of long-term protective immunity "and can help researchers develop better vaccines. "people do worry about whether immunity can be induced after infection with the new coronavirus, and some reports on reinfection have strengthened people's worries. but we now know that normal people can make a strong immune response, which can greatly relieve anxiety. "said Professor Shane Crotty, another research leader. references [1] Yan Wu et al., (2020) a noncomputing pair of human neutralising antibacterials block covid-19 virus binding to its receptor ACE2. Science. Doi: 10.1126/ science.abc2241 [2] Retrieved May 16, 2020, from Grifoni, a, et.al , (2020) Targets of T cell responses to SARS-CoV-2 coronavirus in humans with COVID-19 disease and unexposed individuals, Cell. Doi: T cells found in COVID-19 patients ‘bode well’ for long-term immunity. Retrieved May 16, 2020, from #