On the other hand, it is also important to point out that, while the goal is to produce a safe and effective vaccine, clinical vaccine trials need to closely monitor test subjects for a paradoxical increase in susceptibility to COVID-19 in a manner similar to what occurred during the process of developing a vaccine for dengue fever (Katzelnick et al

On the other hand, it is also important to point out that, while the goal is to produce a safe and effective vaccine, clinical vaccine trials need to closely monitor test subjects for a paradoxical increase in susceptibility to COVID-19 in a manner similar to what occurred during the process of developing a vaccine for dengue fever (Katzelnick et al., 2017). IgM, and day 14 for IgG (Infantino et al., 2020), although another study has shown that the majority of patients seroconverted between 7 and 11?days postexposure to the virus (Patel et al., 2020). A recent report (Haveri et al., 2020) showed that, when using the Western blot, there was a prominent response to the spike protein with convalescent patient sera, which further strengthens the potential role of the spike protein as a target for both serologic testing and vaccine development. In addition, reactivity to the envelope protein and to the nucleocapsid of SARS-CoV-2 by immune sera was detected on immunoblot, making these proteins also potential vaccine candidates (Haveri et al., 2020). On the other hand, it is also important to point out that, while the goal is to produce a safe and effective vaccine, clinical vaccine trials need to closely monitor test subjects for a paradoxical increase in susceptibility to COVID-19 in a manner similar to what occurred during the process of developing a vaccine for dengue fever (Katzelnick et al., 2017). This undesirable situation is based on the hypothesis that a previous immune response to one virus or pathogen Cediranib maleate can paradoxically render a person more susceptible to a subsequent contamination with a slightly different, but antigenically or species-related virus (Tetro, 2020). This phenomenon is known as antibody-dependent enhancement whereby antibodies, rather than neutralizing the virus, actually facilitate viral uptake into the target cell (Modhiran et al., 2010). Lastly, an additional benefit of the Western blot would be to be able to identify unequivocally prospective donors of well characterized plasma to be used for therapeutic purposes in order to treat people most vulnerable towards developing a life-threatening contamination. This is based on its almost unparalleled high level of sensitivity in identifying the key antigens that are evoking an immune response that is potentially protective in patients recovering from COVID-19. In light of the preceding, how do we anticipate antibodies to be effective Cediranib maleate against COVID-19? The answer lies on what we already know about the pattern of inhibition that typically occurs and has been well recognized for many microbes, including most viruses. There are two main mechanisms. One mechanism involves neutralization of the infectivity of the virus by antibody binding to the proteins around the outer surface of the virus. This binding has two effects: (i) it can prevent the conversation of the virus with cell receptors, and (ii) it can cross-link the viral proteins so that uncoating does not occur. The virus, therefore, cannot replicate. Furthermore, antibody-coated virus may be more rapidly phagocytized by macrophages than non-coated virus, a Cediranib maleate process similar to the opsonizing effect of antibody on bacteria. A close in vitro analogy of these anti-viral processes is the plaque reduction neutralization test which can be used to quantify the titer of neutralizing antibody directed against the virus (Schmidt et al., 1976). Unfortunately, it is a somewhat cumbersome test, takes several days before results can be obtained and, given the pathogenicity of SARS-CoV-2, extremely high level containment facilities would be needed to perform this procedure. The second mechanism involves the lysis of virally-infected cells that are forming in the infected host, in the presence of antibody and complement. Antibody binds to Rabbit polyclonal to BMP7 newly produced virus-specific antigens around the cell surface and then binds complement, which enzymatically degrades the cell membrane. Because the host cell is killed before the full yield of virus is produced, the spread of virus is usually significantly reduced. However, another less favorable possibility needs to be considered whereby SARS-CoV-2 could evade either of the two preceding mechanisms. Some viruses, such as herpesviruses, can spread from cell to cell across intercellular bridges eluding the neutralizing effect of antibody (Lodmell et al., 1973). 2.2. DTH reactions DTH responses are a.