A Is For Antibody

University College London Hospitals (UCLH) and AstraZeneca have created, in the laboratory, a long-acting antibody therapy for Sars-CoV-2 (AZD7442), that they expect to be approved by the Medicines and Healthcare products Regulatory Agency next week (https://www.theguardian.com/world/2020/dec/25/uk-scientists-trial-drug-to-prevent-coronavirus-infection-leading-to-disease). Antibodies are the proteins, normally produced by particular white blood cells (so-called 'T' cells), in response to the foreign proteins of invading viruses, bacteria et cetera. They are an important component of the body's immune response and their production, can be triggered by exposure to the disease agent or vaccination. The intention here, is to inject a cocktail of the monoclonal antibodies (these are produced by cloning activated 'T' cells) directly, in the expectation that they will immediately attack the viral particles. The team hope that the cocktail will provide protection against Covid-19 for between 6 and 12 months. Two 'double blind' (where neither the patient nor the doctor knows, until the code is broken, who has received the cocktail and who has received placebo) trials are being carried out in British hospitals (including UCLH) and a network of 100 global sites. The major study (called 'Storm Chaser') involves the cocktail being offered to people, who have been exposed to Covid-19 in the previous 8 days. If the trials are successful, the hope is that the 'immediate immunity' offered by the treatment could be used to stop outbreaks of infection (in families, hospitals, care homes or universities). It might also be used to protect people (especially the elderly) whilst the vaccination programme is being rolled out. The protective effects of vaccination takes some time to develop. A second smaller study ('Provent') will look at the ability of AZD7442 to protect 'immunocompromised' patients from the effects of Covid-19 infections. These individuals have weak immune systems and do not show a normal response to the virus, by producing their own antibodies. Immunocompromising occurs in an AIDS infection (where the HIV virus directly infects and destroys 'T' cells). It also occurs in people getting treatments for cancer or who have had an organ transplant (these last individuals, have to be permanently maintained on immunosuppressive drugs to prevent rejection). Both studies seem likely to increase our armamentarium of therapies for dealing with Covid-19 (perhaps even eliminating the virus from sections of the population). There is no reason why they should not work, as some people have already been helped by being given plasma from recovered Covid-19 patients (this would contain antibodies). A slight worry (and I do mean slight) is that the monoclonial antibodies are, in effect, foreign proteins. In the case of non-immunocompromised patients, there is a possibility of developing antibodies to the antibodies. That might make the patient (whose 'T' cells have not been primed by the virus) less responsive to a subsequent treatment with the AZD77442 cocktail. I am sure, however, that this will be looked at.