Potential Sialidase From Bacteria Clostridium PerfringensType A as Competitive Inhibitorat Receptor Sialic Acid against Viral Infection Newcastle Disease
By: drh. Ryan Septa Kurnia, M.Si
The Newcastle Disease (ND) virus or disease is known to cause very high economic losses due to decreased production and death of poultry. In Indonesia, ND in poultry has been known since 1926 on the island of Java. Disease control in the form of cages and vaccinations has been carried out to prevent infection by the virus. However, up to now, this case can still be found throughout the year with a 70-80% mortality rate. The diversity of types and the ease with which the virus can change is one of the obstacles to controlling the disease.
The need to develop strategies to control viral infections is a challenge in biomedical science. The use of antiviral substances such as rimantadine, amantadine, ribavirin, and zanamivir can be developed to prevent disease in a relatively short time. However, this is not possible in the poultry industry due to economic considerations and increases the risk of developing viral resistance to antiviral substances. Research related to efforts to inhibit viral infection has been carried out by degrading receptors on host cells using enzymes derived from bacteria. The addition of sialidase is expected to be carried out to be the initial step of viral infection through the respiratory tract. Therefore, in this dissertation research, observations will be made on the efficacy of sialidase from the bacterium Clostridium perfringens as a prophylactic antiviral agent to destroy the entrance of viruses located in target cells.
This research was implemented with the bacteria C. perfringens which can produce the highest sialidase enzyme. Furthermore, observations were made on the enzymatic activity of the sialidase protein derived from the bacterium C. perfringens. Sialidase produced from these bacteria is then purified by several methods so that it can remove other compounds that can interfere with the working mechanism of sialidase. The entrance to the active substance and toxicity is also done to get the optimum dose to destroy the virus. The potency of sialidase as a competitive inhibitor was carried out with in vitro and ovo models based on a challenge test with the virus later.
they are carried out on the ability to inhibit viral infection, and interferon and molecular cytokine responses in cells. The virus model in this study is the ND virus of the Paramyxoviridae family which infects host cells through the sialic acid receptor and causes economic losses in the poultry farming industry. Sialidase is expected to be used as an alternative preventive measure in controlling ND virus outbreaks because it can be produced economically.
The results showed that the sialidase method could be purified directly from the supernatant from the bacterial culture C. perfringens and then with various protein purification methods to get the fraction with the highest enzymatic activity. The pure sialidase can be stable at pH 7 at 37℃ for 72 hours with a gradual decrease in activity. Based on the possibility of toxicity in vitro showed that the dose of 187.5 mU is the safest dose to use. At this dose, it can destroy the entrance of the virus up to 54% so that there is interference with the mechanism of ND virus infection in host cells. These results are also supported by the low expression of cytokines and molecules which are the response of cells to the presence of ND infection viruses in the form of Interferons and Toll-Like Receptors at doses of 750 mU to 46.87 mU. on the number of viruses in the cells also showed that there was no virus multiplication compared to the challenge group without additional treatment. In contrast to other viral drugs that work by targeting the virus, sialidase acts more generally at the entrance known as sialic acid. The loss of the entrance causes inhibition of viral infection in cells so that cells do not experience infection.
In conclusion, sialidase originating from C. perfringens bacteria can be produced efficiently and can inhibit ND virus infection in cells in vitro. However, further tests on experimental animals need to be carried out to describe and observe the effectiveness of sialidase in inhibiting infection with the ND virus and several viruses that have the same entrance.