Vaccines and Antibodies: Weapons in the Fight Against Ebola Virus

Ebola virus disease is one of the deadliest infections in the world today. The microbe to blame is the Ebola virus. It has already caused numerous outbreaks in Africa, in the regions located south of the Sahara. This article describes the main characteristics of this infectious disease as well as the currently available treatments, namely vaccines and antibodies. Antibodies are produced by the human body when it is infected by a microbe. Antibodies can be collected from the blood of infected humans or animals and purified or manufactured in a laboratory to produce drugs. While vaccines have demonstrated their effectiveness in preventing infectious diseases, antibodies are effective in stopping the progression of several infectious diseases. In this article, you will discover that the stimulation of the immune system, either by the vaccine or by antibodies, is essential to tackle Ebola virus disease.


Figure Figure
Transmission of Ebola virus to humans. Bats can be infected with Ebola virus without getting sick, and they can then spread the virus to other animals or directly to humans. Humans can also contract Ebola by handling sick or infected animals that were previously infected by bats. Infected humans can spread the virus to each other via bodily fluids, including blood, saliva, urine, and vomit.

EBOLA VIRUS ORIGIN AND TRANSMISSION TO HUMANS
Ebola virus was identified for the first time in . Since its discovery, the virus has already caused more than outbreaks in Africa. These outbreaks are quite deadly: it was estimated that if people were infected by the Ebola virus, < people would survive [ -]. Ebola virus infections appear in equatorial sub-Saharan Africa , particularly in https://en.m. wikipedia.org/ wiki/Sub-Saharan_Africa Sudan, Uganda, Gabon, and the Democratic Republic of Congo. Ebola virus disease originates from animals. Fruit bats naturally harbor Ebola virus, which means that the virus lives inside the bats without harming them. Hence, bats are the natural reservoirs of the Ebola virus. The Ebola virus can jump from bats to other species such as humans and apes ( Figure ).
Ebola virus infections occur when viral particles are absorbed through the mouth, the skin, or through skin wounds. Humans can become infected when handling sick or dead infected animals or by close contact with bats that have the virus. They can also be infected by other humans, for example by contact with blood, saliva, urine, breast milk, semen, sweat, stool, or vomit from infected people. Humans can also be infected through soiled clothing, bedding, gloves, protective equipment, and medical waste, such as syringes. You can see why people need to use extreme caution if they deal with infected patients in hospitals or dead people at funerals. infect cells (Figure ). If an infection occurs, the immune system of an infected animal will spot these spike glycoproteins and will fight the virus, by calling its immune soldiers onto the field.
Ebola virus disease does not start right away after infection. There is a lag of -days, called the incubation period, before the replication of the virus causes the first symptoms appear. Ebola virus disease starts with high fever, malaise, fatigue, and body aches. Then gastrointestinal symptoms, such as vomiting and diarrhea, appear, which lead to drastic fluid losses of up to l a day. While some patients recover, others su er from bleeding and kidney damage, eventually leading to multiple organ failure and death. To diagnose Ebola virus disease, a blood sample is taken from the infected person and examined for the presence of viral particles.

LYMPHOCYTES: THE HEROES OF THE IMMUNE SYSTEM
Against microbes, and viruses in particular, there are two modes of protection. The first one is to avoid contact with infected people, by respecting a physical distance as proposed for Covid-. Arthur Semmelweis was the first to promote hand washing back in the s, making hand washing the oldest preventive measure. The French biologist Louis Pasteur, who was afraid of germ transmission, never shook hands. The second type of protection is provided by the immune system. The immune system defends the body against all types of microbes, using cells and molecules that work together to prevent disease-causing organisms from causing infection. If a microbe succeeds in infecting the body, the immune system will kill the microbe or the infected cells, thanks to the action of its soldiers.
There are two types of immune system soldiers: lymphocytes and antibodies. Lymphocytes are cells that travel through the blood and LYMPHOCYTE White blood cells that belong to the immune system and protect against dangerous microbes. various tissues. They are activated by microbes and react against them. Some lymphocytes can directly kill infected cells: they are called cytotoxic T cells. Other lymphocytes, called B cells, produce antibodies, which are molecules that circulate in blood and other

THE EBOLA VACCINE FOR PREVENTION OF DISEASE
The best way to prevent people from getting infected with Ebola virus is to vaccinate them against the virus. Vaccination consists of VACCINATION Giving a person or animal a preparation to stimulate the immune system, to protect against infection with a dangerous microbe. giving a person one or more antigens from the microorganism. These antigens are just parts of the virus and do not cause the disease. Still, the antigens stimulate B cells to make neutralizing antibodies that will circulate in the blood of the vaccinated individual and prepare the immune system to fight the virus more rapidly and e ciently if it is encountered later ( Figure A). For the Ebola vaccine, the antigen selected is the spike glycoprotein. To produce a vaccine capable of stimulating the immune system and producing neutralizing antibodies, scientists attached the spike glycoprotein to a di erent, completely harmless virus. The harmless virus carrying the Ebola spike glycoprotein produces large amounts of the Ebola virus spike glycoprotein when it is injected into people. This leads the vaccinated person to produce of high levels of protective neutralizing antibodies against the spike glycoprotein [ ].
This Ebola virus vaccine was proven e ective in Guinea during an outbreak in west Africa. The vaccine worked well when given as a single shot, and the study indicated that the vaccine could help people to build immunity rapidly. This is good, because it means the vaccine could be used when an Ebola outbreak is first identified, to protect people before they are exposed to the virus. Other vaccine candidates have been proposed, and although they take longer to stimulate immunity, they may provide an immune response that lasts longer. To successfully vaccinate populations at risk of Ebola, some important issues must be addressed. For example, the Ebola virus vaccine must be kept in a cold environment until it is used, which can be di cult in remote areas. Also, populations must agree to be vaccinated, which is often a huge challenge because a significant percentage of people are frightened by vaccination and do not understand that by vaccinating themselves not only are they protecting themselves but also protecting others from the transmission of the virus.

ADMINISTRATION OF ANTIBODIES FOR TREATMENT OF DISEASE
If a person is already infected with Ebola virus, there is no time for a vaccine to do its work stimulating the immune system. But neutralizing antibodies from other people or animals can still help! Such antibodies can be injected into an infected person, where they can directly neutralize the virus and decrease its spread from one cell to another ( Figure B). In the past, these antibodies were obtained from the blood of infected animals or humans. Today, we use antibodies produced in laboratories, which are created to recognize a specific antigen from the virus. These are called monoclonal antibodies [ ]. A single

MONOCLONAL ANTIBODIES
antibodies produced by the same population of lymphocytes, specifically recognizing the same antigen. monoclonal antibody can be given, or patients might receive a mixture of monoclonal antibodies that recognize di erent viral antigens.  . doi: . /frym. .

CONFLICT OF INTEREST:
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
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