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Department of Microbiology and Physiological Systems; Program in Microbiology and Immunology

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Amino Acids, Peptides, and Proteins | Immunology of Infectious Disease | Immunopathology | Immunoprophylaxis and Therapy | Maternal and Child Health | Respiratory Tract Diseases | Virology | Virus Diseases | Viruses


Respiratory syncytial virus (RSV) infection poses a significant risk for infants. Since the direct vaccination of infants is problematic, maternal vaccination may provide a safer, more effective approach to their protection. In the cotton rat (CR) model, we have compared the immunization of pregnant CR dams with virus-like particles assembled with the prototype mutation stabilized pre-fusion F protein, DS-Cav1, as well two alternative mutation stabilized pre-fusion proteins (UC-2 F, UC-3 F) and showed that the alternative pre-fusion F VLPs protected the offspring of immunized dams significantly better than DS-Cav1 F VLPs (Blanco, et al. J. Virol. 93: e00914). Here, we have addressed the reasons for this increased protection by characterizing the specificities of antibodies in the sera of both immunized dams and their offspring. The approach was to measure the levels of total anti-pre-F IgG serum antibodies that would block the binding of representative pre-fusion specific monoclonal antibodies to soluble pre-fusion F protein targets. Strikingly, we found that the sera in most offspring of DS-Cav1 F VLP-immunized dams had no mAb D25-blocking antibodies, although their dams had robust levels. In contrast, all offspring of UC-3 F VLP-immunized dams had robust levels of these D25-blocking antibodies. Both sets of pup sera had significant levels of mAb AM14-blocking antibodies, indicating that all pups received maternal antibodies. A lack of mAb D25-blocking antibodies in the offspring of DS-Cav1 F VLP-immunized dams may account for the lower protection of their pups from challenge compared to the offspring of UC-3 F VLP-immunized dams.


antibodies, maternal antibodies, pre-fusion F proteins, vaccines, virus-like particles

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© 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (

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Cullen LM, Boukhvalova MS, Blanco JCG, Morrison TG. Comparisons of Antibody Populations in Different Pre-Fusion F VLP-Immunized Cotton Rat Dams and Their Offspring. Vaccines (Basel). 2020 Mar 18;8(1):E133. doi: 10.3390/vaccines8010133. PMID: 32197348. Link to article on publisher's site

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Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.