ADE
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8459929/
Hum Vaccin Immunother. 2021; 17(11): 4121–4125.
Published online 2021 Sep 20. doi: 10.1080/21645515.2021.1969855
PMCID: PMC8459929
PMID: 34543154
Early insight into antibody-dependent enhancement after SARS-CoV-2 mRNA vaccination
ABSTRACT
Current vaccines, which induce a B-cell-mediated antibody response against the spike protein of SARS-CoV-2, have markedly reduced infection rates. However, the emergence of new variants as a result of SARS-CoV-2 evolution requires the development of novel vaccines that are T-cell-based and that target mutant-specific spike proteins along with ORF1ab or nucleocapsid protein. This approach is more accommodative in inducing highly neutralizing antibodies, without the risk of antibody-dependent enhancement, as well as memory CD8+T-cell immunity.
To the Editor,
Immunity against severe acute respiratory syndrome coronavirus (SARS-CoV)-2 infection is an important topic of investigation in COVID-19 research. The analysis of immune correlates has helped in the design of many vaccines against SARS-CoV-2. To date, there are 108 candidate vaccines under clinical development and 184 vaccines in pre-clinical development. Three vaccines have been shown to have more than 90% efficacy in clinical trials. These include the mRNA-based vaccines BNT162b11 and mRNA-1273,2 and the chimpanzee adenovirus vectored vaccine ChAdOx1 nCoV-19 (AZD1222).3 The vaccine trial with BNT162b1, which is a lipid nanoparticle-formulated nucleoside-modified mRNA that encodes the receptor-binding domain (RBD) of the SARS-CoV-2 spike (S)-protein, reported efficacy in adults. In most participants, BNT162b1 elicited robust RBD-specific CD4+ type 1 T-helper (Th1)-biased responses and strong neutralizing antibody responses. The anti-RBD IgG levels were higher in individuals who received the vaccine compared to those who had a natural infection and were capable of neutralizing pseudoviruses with diverse SARS-CoV-2 S-protein variants.1 Similarly, the vaccine trial with mRNA-1273, which is a lipid nanoparticle-encapsulated mRNA-based vaccine that encodes the prefusion stabilized full-length S-protein, elicited primary CD4+ Th1-biased responses and high levels of neutralizing antibodies.2 The adenovirus-vectored vaccine AZD1222 was also shown to be successful in inducing anti-S-IgG responses.3 Accordingly, these three vaccine types have been authorized by the World Health Organization (WHO) for emergency use4,5 and are mainly being administered in North America and Europe, among other countries. In addition, a number of other vaccines are being administered in various parts of the world; these include Ad26.COV2.S (viral vector; authorized for emergency use by WHO), BBIBP-CorV (inactivated virus; authorized for emergency use by WHO),4,5 CoviVac (viral vector), Gam-COVID-Vac (Sputnik V; viral vector), CoronaVac (inactivated virus), Covaxin (inactivated virus), QazCovid-in (inactivated virus), EpiVacCorona (protein subunit),4 Sputnik Light (viral vector), Convidecia (viral vector), WIBP-CorV (inactivated virus), Minhai (inactivated virus), COVIran Barakat (inactivated virus), Zifivax (protein subunit), Abdala (protein subunit), Soberana 02 (protein subunit) and MVC-COV1901 (protein subunit). Moreover, early clinical data have shown great promise with the NVX-CoV2373 (Novavax) vaccine, which is a recombinant nanoparticle that contains the full-length S-glycoprotein of the prototype strain plus Matrix-M adjuvant.6 Generally, the aforementioned vaccines confer between 50 and 95% protection against SARS-CoV-2 infection.
pt 1