Coronavirus: questo virus straconosciuto
J Virol. 10.1128/JVI.75.20.9741-9752.2001
Molecular Determinants of Species Specificity in the Coronavirus Receptor Aminopeptidase N (CD13): Influence of N-Linked Glycosylation
In una pubblicazione scientifica del 2004
J Virol. 2004 Aug; 78(16): 8701–8708.
Human Coronavirus 229E Binds to CD13 in Rafts and Enters the Cell through Caveolae
Queste due pubblicazioni del 2001 e del 2004 dimostrano che i Coronavirus non sono così sconosciuti, anzi straconusciuti e studiati, anche la loro composizione è straconosciuta e l’enfasi che attualmente è stata identificata la composizione dei Coronavirus, è giunta con ben 19 anni di ritardo.
“ L'aminopeptidasi N (APN), una metalloproteasi di 150 kDa chiamata anche CD13, funge da recettore per i coronavirus sierologicamente correlati dell'uomo.”
“ I coronavirus umani (HCoV) sono un'importante causa di infezione del tratto respiratorio superiore. Studi sierologici suggeriscono che causano dal 15 al 30% delle infezioni o raffreddori delle vie respiratorie umane, le persone possono essere ripetutamente infettate dallo stesso ceppo. I coronavirus hanno una membrana lipidica che ha grandi peplomeri che sporgono dal virione e gli danno l'aspetto di una corona. Questi peplomeri o glicoproteine a spillo sono le proteine di attaccamento virale.”
I coronavirus utilizzano il recettore CD13, si lega a questo recettore per entrare nella cellula ed infettarla.
“Nel presente studio, abbiamo effettivamente osservato che la particella virale, inizialmente legata alla superficie cellulare apparentemente in modo casuale, si aggregava alle proteine delle membrane chiamate caveolae in modo dipendente dal colesterolo. Inoltre, l'esaurimento del colesterolo hanno inibito l'ingresso del virus nelle cellule. I risultati indicano che l'integrità del micro dominio ricco di sfingolipidi e colesterolo è indispensabile per l'infezione da Coronavirus e suggeriscono che la manipolazione dei lipidi di membrana potrebbe essere utilizzata come misura preventiva.”
Utilizzando l’antirecettore CD13 è possibile impedire l’ingresso dei Coronavirus nelle cellule, come affermato nelle due pubblicazioni del 2001 e del 2004.
Per poter effettuare questa prevenzione e terapia, occorre rivolgersi alla immunofarmacologia omeopatica, all’omeopatia e all’omotossicologia, in queste discipline mediche sono presenti tutti i farmaci che prevengono e curano le patologie infiammatorie.
La componente infettiva, la presenza di virus, batteri intracellulari, batteri extracellulari è fondamentale, non evidenziare questa componente infettiva rende non scientifica ogni ricerca.
Semplicissimo privo di ogni allarmismo, effetto paura.
ABSTRACT
Aminopeptidase N (APN), a 150-kDa metalloprotease also called CD13, serves as a receptor for serologically related coronaviruses of humans (human coronavirus 229E [HCoV-229E]), pigs, and cats. These virus-receptor interactions can be highly species specific; for example, the human coronavirus can use human APN (hAPN) but not porcine APN (pAPN) as its cellular receptor, and porcine coronaviruses can use pAPN but not hAPN. Substitution of pAPN amino acids 283 to 290 into hAPN for the corresponding amino acids 288 to 295 introduced an N-glycosylation sequon at amino acids 291 to 293 that blocked HCoV-229E receptor activity of hAPN. Substitution of two amino acids that inserted an N-glycosylation site at amino acid 291 also resulted in a mutant hAPN that lacked receptor activity because it failed to bind HCoV-229E. Single amino acid revertants that removed this sequon at amino acids 291 to 293 but had one or five pAPN amino acid substitution(s) in this region all regained HCoV-229E binding and receptor activities. To determine if other N-linked glycosylation differences between hAPN, feline APN (fAPN), and pAPN account for receptor specificity of pig and cat coronaviruses, a mutant hAPN protein that, like fAPN and pAPN, lacked a glycosylation sequon at 818 to 820 was studied. This sequon is within the region that determines receptor activity for porcine and feline coronaviruses. Mutant hAPN lacking the sequon at amino acids 818 to 820 maintained HCoV-229E receptor activity but did not gain receptor activity for porcine or feline coronaviruses. Thus, certain differences in glycosylation between coronavirus receptors from different species are critical determinants in the species specificity of infection.
Human Coronavirus 229E Binds to CD13 in Rafts and Enters the Cell through Caveolae
ABSTRACT
CD13, a receptor for human coronavirus 229E (HCoV-229E), was identified as a major component of the Triton X-100-resistant membrane microdomain in human fibroblasts. The incubation of living fibroblasts with an anti-CD13 antibody on ice gave punctate labeling that was evenly distributed on the cell surface, but raising the temperature to 37°C before fixation caused aggregation of the labeling. The aggregated labeling of CD13 colocalized with caveolin-1 in most cells. The HCoV-229E virus particle showed a binding and redistribution pattern that was similar to that caused by the anti-CD13 antibody: the virus bound to the cell evenly when incubated on ice but became colocalized with caveolin-1 at 37°C; importantly, the virus also caused sequestration of CD13 to the caveolin-1-positive area. Electron microscopy confirmed that HCoV-229E was localized near or at the orifice of caveolae after incubation at 37°C. The depletion of plasmalemmal cholesterol with methyl β-cyclodextrin significantly reduced the HCoV-229E redistribution and subsequent infection. A caveolin-1 knockdown by RNA interference also reduced the HCoV-229E infection considerably. The results indicate that HCoV-229E first binds to CD13 in the Triton X-100-resistant microdomain, then clusters CD13 by cross-linking, and thereby reaches the caveolar region before entering cells.
Human Coronavirus 229E Binds to CD13 in Rafts and Enters the Cell through Caveolae
ABSTRACT
CD13, a receptor for human coronavirus 229E (HCoV-229E), was identified as a major component of the Triton X-100-resistant membrane microdomain in human fibroblasts. The incubation of living fibroblasts with an anti-CD13 antibody on ice gave punctate labeling that was evenly distributed on the cell surface, but raising the temperature to 37°C before fixation caused aggregation of the labeling. The aggregated labeling of CD13 colocalized with caveolin-1 in most cells. The HCoV-229E virus particle showed a binding and redistribution pattern that was similar to that caused by the anti-CD13 antibody: the virus bound to the cell evenly when incubated on ice but became colocalized with caveolin-1 at 37°C; importantly, the virus also caused sequestration of CD13 to the caveolin-1-positive area. Electron microscopy confirmed that HCoV-229E was localized near or at the orifice of caveolae after incubation at 37°C. The depletion of plasmalemmal cholesterol with methyl β-cyclodextrin significantly reduced the HCoV-229E redistribution and subsequent infection. A caveolin-1 knockdown by RNA interference also reduced the HCoV-229E infection considerably. The results indicate that HCoV-229E first binds to CD13 in the Triton X-100-resistant microdomain, then clusters CD13 by cross-linking, and thereby reaches the caveolar region before entering cells.
