In novel potent antibody and vaccine development, identifying the most
sensitive amino acid fragment of the target antigen is very critical
issue. Taking the advantage for the new study similarity in nucleic acid
sequence and host ACE2 receptors in SARS-CoV-1 and SARS-CoV-2 is
important. An impressive study was reported that S1 subunit protein
amino acid residue from 318-510 bounds ACE2 host very efficiently than
the full length S1 daman (amino acid residue
12-672).60 Furthermore, amino acid residue 327-510 and
318-490 did not detectably bind to detect ACE2. Interestingly, the major
reason was investigated as the reason that about 7 amino acid cysteine
which are 5 of them essential to ACE2 expression and the aspartic acid,
glutamic acid amino acid which also have an important association with
ACE2 are found within 318-510 amino acid (aa) residue
domains.60
Figure 4. S1 subunit spiked protein SARS-CoV-1 amino acid
residue domain. The aa represents for: amino acid residue, N: N-
Terminal, C: C-Terminal.
In the same fashion, recently the receptor-biding domain (RBM) in the
S-protein COVID-19 apparently amino acid residue (Gln493) showed
favorable interactions with human ACE2 and the binding sites of S
protein COVID-19 to human ACE2 were identified as residues 455, 486,
493, 501, and 505.39 So that, taking those critical
scientific evidence could lead to produce robust neutralizing antibody
and vaccine against COVID-19.
Surprisingly, from the recent study reported that, the monoclonal
antibody CR3022 only showed a cross reactivity of SARS-Cov-1 with spiked
protein of COVID-19. However, m396 and CR3014 failed to bind the RBD of
COVID-19. 48 This CR3022 is developed from
convalescent serum SARS-CoV-1 patient B lymphocyte single chain variable
antibody fragment (scFv) phage display library.50 This
antibody is targeted a C-terminal of sensitive amino acid residue from
318-510 of spiked protein RBD SARA-CoV-1 Moreover, this antibody is
targeted spiked protein of RBD. 48 Similar study was
reported only ACE2-non-blocking SARS-CoV-1 RBD antibodies was shown a
positive cross reactivity with COVID-19. 18 Thus, we
suggest that further more studies and CR3022 may have the therapeutic
and diagnostic potential alone or in combination with other neutralizing
antibodies, for the prevention and treatment of COVID-19 infections.
Production of novel antibody and vaccine based on those very important
scientific backgrounds is an urgent needed. 48
Plasma serum containing polyclonal antibody from fully recovered patient
is as an immediate optional therapy against COVID-19 to slowdown spread
and save live.24 However, getting enough recovered
volunteer donors and transfusion compatibility remind as big challenges.
In order to overcome this draw back, improved method for EBV
(Epstein–Barr virus) immortalization transformation of human B cells
which secrets a neutralization antibody have been
developed.61,62 interestingly, specific monoclonal
antibody isolated from EBV transformed B cell of patients recovered from
severe acute respiratory syndrome coronavirus (SARS-CoV-1) infection
resulted in vitro neutralizing efficiency from 10–8M to
10–11M.63 Surprisingly, monoclonal antibody CR3022
which was developed from B cell SARS-CoV-1 recovered patients showed a
dramatic cross reactivity binding potential for
COVID-19.48 Blood group O individuals was shown very
low risk of infection against COVID-19. Moreover, convalescent plasma
taking from O blood group recovered individuals results better
efficacy.12,13,22 Taking all together, isolation of
specific monoclonal antibody from EBV transformed B lymphocyte of fully
recover ABO blood group typically O could be an effective approach at
this very critical emergency time to overcome COVID-19 pandemic.