PCR amplification of antibody variable regions using primers that anneal to constant regions

Antibody-guided structure-based vaccines

The vaccine field is pursuing diverse approaches to translate the molecular insights from analyses of effective antibodies and their targeted epitopes into immunogens capable of eliciting protective immune responses. Here we review current antibody-guided strategies including conformation-based, epitope-based, and lineage-based vaccine approaches, which are yielding promising vaccine candidates now being evaluated in clinical trials. We summarize directions being employed by the field, including the use of sequencing technologies to monitor and track developing immune responses for understanding and improving antibody-based immunity. We review opportunities and challenges to transform powerful new discoveries into safe and effective vaccines, which are encapsulated by vaccine efforts against a variety of pathogens including HIV-1, influenza A virus, malaria parasites, respiratory syncytial virus, and SARS-CoV-2. Overall, this review summarizes the extensive progress that has been made to realize antibody-guided structure-based vaccines, the considerable challenges faced, and the opportunities afforded by recently developed molecular approaches to vaccine development.

Production of functional antibodies generated in a nonlytic insect cell expression system

A monoclonal antibody directed against the type 2 adenovirus (Ad2) penton base protein was cloned and expressed in Spodoptera frugiperda (Sf9) cells using a nonlytic vector system. The coding sequences for the immunoglobulin light and heavy chains were placed under the control of the Orgyia pseudotsugata multicapsid nucleopolyhedrosis virus immediate-early 2 (OpIE2) promoter. Transfected Sf9 cells continuously secreted the antibody which retained the ability to recognize both native and recombinant Ad2 penton base proteins. Bifunctional penton base antibodies were also generated by fusing a gene for a growth factor or a cytokine at the 3' end of the Ig constant heavy chain domain. The quantity and activity of recombinant antibodies generated in the nonlytic insect cell system could be determined relatively quickly compared to other expression systems. Moreover, these recombinant proteins were not subjected to proteolytic degradation as frequently occurs during baculovirus-mediated cell lysis and the levels of recombinant antibodies produced in the nonlytic system were comparable to those reported for cytolytic baculovirus vectors.

PCR strategies for isolation of the 5' end of an immunoglobulin-encoding bovine cDNA

We have employed two in vitro amplification strategies in our attempts to characterise the variable region of bovine immunoglobulin heavy chains (VH). Products derived by 5' RACE (rapid amplification of cDNA ends) spanned the coding sequence, but diversity in the complementarity determining regions was highly restricted, indicating that a limited subset of the heavy-chain repertoire had been recovered. In contrast, unique, full-length VH determinants were obtained with ease by an inverse application of the polymerase chain reaction. The strength of this approach is considerable: it is straightforward to perform, requiring none of the tailing procedures inherent to RACE strategies, yet it enables the rapid isolation of uncharacterized regions of genes for which limited sequence data are available. Our findings suggest strongly that the heavy-chain repertoire of cattle is highly dependent upon a very limited number of germline VH and JH (joining region) gene families.