TY - JOUR
T1 - Immunogenicity and Protective Efficacy of a Highly Thermotolerant, Trimeric SARS-CoV-2 Receptor Binding Domain Derivative
AU - Malladi, Sameer Kumar
AU - Patel, Unnatiben Rajeshbhai
AU - Rajmani, Raju S.
AU - Singh, Randhir
AU - Pandey, Suman
AU - Kumar, Sahil
AU - Khaleeq, Sara
AU - Van Vuren, Petrus Jansen
AU - Riddell, Shane
AU - Goldie, Sarah
AU - Gayathri, Savitha
AU - Chakraborty, Debajyoti
AU - Kalita, Parismita
AU - Pramanick, Ishika
AU - Agarwal, Nupur
AU - Reddy, Poorvi
AU - Girish, Nidhi
AU - Upadhyaya, Aditya
AU - Khan, Mohammad Suhail
AU - Kanjo, Kawkab
AU - Bhat, Madhuraj
AU - Mani, Shailendra
AU - Bhattacharyya, Sankar
AU - Siddiqui, Samreen
AU - Tyagi, Akansha
AU - Jha, Sujeet
AU - Pandey, Rajesh
AU - Tripathi, Shashank
AU - Dutta, Somnath
AU - McAuley, Alexander J.
AU - Singanallur, Nagendrakumar Balasubramanian
AU - Vasan, Seshadri S.
AU - Ringe, Rajesh P.
AU - Varadarajan, Raghavan
N1 - Publisher Copyright:
© 2021 American Chemical Society.
PY - 2021/8/13
Y1 - 2021/8/13
N2 - The receptor binding domain (RBD) of SARS-CoV-2 is the primary target of neutralizing antibodies. We designed a trimeric, highly thermotolerant glycan engineered RBD by fusion to a heterologous, poorly immunogenic disulfide linked trimerization domain derived from cartilage matrix protein. The protein expressed at a yield of ∼80-100 mg/L in transiently transfected Expi293 cells, as well as CHO and HEK293 stable cell lines and formed homogeneous disulfide-linked trimers. When lyophilized, these possessed remarkable functional stability to transient thermal stress of up to 100 °C and were stable to long-term storage of over 4 weeks at 37 °C unlike an alternative RBD-trimer with a different trimerization domain. Two intramuscular immunizations with a human-compatible SWE adjuvanted formulation elicited antibodies with pseudoviral neutralizing titers in guinea pigs and mice that were 25-250 fold higher than corresponding values in human convalescent sera. Against the beta (B.1.351) variant of concern (VOC), pseudoviral neutralization titers for RBD trimer were ∼3-fold lower than against wildtype B.1 virus. RBD was also displayed on a designed ferritin-like Msdps2 nanoparticle. This showed decreased yield and immunogenicity relative to trimeric RBD. Replicative virus neutralization assays using mouse sera demonstrated that antibodies induced by the trimers neutralized all four VOC to date, namely B.1.1.7, B.1.351, P.1, and B.1.617.2 without significant differences. Trimeric RBD immunized hamsters were protected from viral challenge. The excellent immunogenicity, thermotolerance, and high yield of these immunogens suggest that they are a promising modality to combat COVID-19, including all SARS-CoV-2 VOC to date.
AB - The receptor binding domain (RBD) of SARS-CoV-2 is the primary target of neutralizing antibodies. We designed a trimeric, highly thermotolerant glycan engineered RBD by fusion to a heterologous, poorly immunogenic disulfide linked trimerization domain derived from cartilage matrix protein. The protein expressed at a yield of ∼80-100 mg/L in transiently transfected Expi293 cells, as well as CHO and HEK293 stable cell lines and formed homogeneous disulfide-linked trimers. When lyophilized, these possessed remarkable functional stability to transient thermal stress of up to 100 °C and were stable to long-term storage of over 4 weeks at 37 °C unlike an alternative RBD-trimer with a different trimerization domain. Two intramuscular immunizations with a human-compatible SWE adjuvanted formulation elicited antibodies with pseudoviral neutralizing titers in guinea pigs and mice that were 25-250 fold higher than corresponding values in human convalescent sera. Against the beta (B.1.351) variant of concern (VOC), pseudoviral neutralization titers for RBD trimer were ∼3-fold lower than against wildtype B.1 virus. RBD was also displayed on a designed ferritin-like Msdps2 nanoparticle. This showed decreased yield and immunogenicity relative to trimeric RBD. Replicative virus neutralization assays using mouse sera demonstrated that antibodies induced by the trimers neutralized all four VOC to date, namely B.1.1.7, B.1.351, P.1, and B.1.617.2 without significant differences. Trimeric RBD immunized hamsters were protected from viral challenge. The excellent immunogenicity, thermotolerance, and high yield of these immunogens suggest that they are a promising modality to combat COVID-19, including all SARS-CoV-2 VOC to date.
KW - glycosylation
KW - oligomerization
KW - thermostable
KW - vaccine
KW - variant of concern
UR - http://www.scopus.com/inward/record.url?scp=85111330528&partnerID=8YFLogxK
U2 - 10.1021/acsinfecdis.1c00276
DO - 10.1021/acsinfecdis.1c00276
M3 - Article
C2 - 34260218
AN - SCOPUS:85111330528
SN - 2373-8227
VL - 7
SP - 2546
EP - 2564
JO - ACS Infectious Diseases
JF - ACS Infectious Diseases
IS - 8
ER -