It is a ‘functional ancestor of antibodies’, which helps to explain why some people are less susceptible to the effects of infection
Discovered a new mechanism of resistance of our organism towards the Sars-Cov2 virus which could lead to the fine-tuning of new drugs and new markers to assess disease severity.
It is the result of an international research, published on Nature Immunology and coordinated byHumanitas Institute and fromSan Raffaele Hospital in Milan. The attention of scientists has focused in particular on Mannose Binding Lectin (in abbreviation Mbl), one of the so-called “functional ancestors of antibodies”, proteins capable of attacking the virus in ways similar to those of real antibodies, which however they are part of innate immunity.
Innate immunity
Innate immunity constitutes the first line of defense against viruses, bacteria and more. It includes cells of the immune system which, with different mechanisms, attack pathogens by organizing a timely response while waiting for the organism to equip itself for targeted defense (adaptive immunity), which is expressed through the actual antibodies. However, there is also a part of the innate immunity formed by circulating molecules (hence called humoral) to which Mbl belongs, among others.
Link with variants
“We found that Mbl binds to the Spike protein of the virus and blocks it – explains the professor Alberto Mantovani, scientific director of Humanitas and professor of Humanitas University -. And we have verified that is able to do this with all tested variants, including Omicron ‘. “This is made possible by the fact that Mbl is linked to certain” sugars “of the Spike protein, which do not change from variant to variant,” explains Elisa Vicenzi, head of the Viral Pathogenesis and Biosecurity Unit of the Irccs San Raffaele Hospital, who adds: “In vitro Mbl proved to be slightly less powerful than the antibodies produced by patients recovered from Covid.” «With Professor Cecilia Garlanda, who participated in the coordination of the study, we are proceeding to optimize Mbl to understand if it will be possible to transform it into a drug»Resumes Mantovani. «The road is long but it is important to try to have other weapons available against the virus. Among other things, Mbl has already been infused by other researchers and clinicians as a therapy in subjects with complete genetic deficiency and has been well tolerated ».
Gravity markers
Another use of Mbl could be that of a marker of the severity of Covid-19. “We have found that genetic variants that produce different quantities of circulating Mbl are associated with different severity of the disease” explains Mantovani. «And this represents an extra step in the understanding of which genetic traits influence susceptibility to the virus“. As a marker, the Ptx3 protein, also investigated in the same study (funded significantly by Dolce & Gabbana). «Ptx3 could be a particularly useful marker because it is produced and secreted by innate immunity cells right at the bronchial level. And it seems one of the best candidates for long-covid gravity indicator»Underlines Mantovani.
Vaccines
Returning to Mbl, a question that may arise is why should we continue to vaccinate if we already have such an effective natural defense? “First of all, because no drug can compete with a vaccine for individual and social efficacy and sustainability”, the professor points out. «Secondly, because if it is true that the innate immune response is proving to be more and more important, e might explain, also through these observations, because many people manage to “get away” with an infection that has no serious outcome, it also remains true that there is a great variability in this response and the reinforcement given by specific antibodies is fundamental because it guarantees everyone a good defense. We do not yet know in advance who will be able to do it alone and who will not“.
Perspectives
How do you see the future regarding the pandemic? «I am optimistic, because if I look back two years ago I remember that we had an empty cupboard both in the diagnostic, preventive and therapeutic fields. We now have 10 vaccines already available, 40 in clinical trials and even more in preclinical trials. We have drugs and monoclonal antibodies. I think we are heading towards normalcy again. Maybe it will be a slightly different normality: perhaps we will not find it strange to wear the mask as it happened in the East before Covid but in any case in a different situation from that of the last two years “.
January 31, 2022 (change January 31, 2022 | 17:09)
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