High-throughput isolation of immunoglobulin genes from single human B cells and expression as monoclonal antibodies.
ABSTRACT Defining human B cell repertoires to viral pathogens is critical for design of vaccines that induce broadly protective antibodies to infections such as HIV-1 and influenza. Single B cell sorting and cloning of immunoglobulin (Ig) heavy- and light-chain variable regions (V(H) and V(L)) is a powerful technology for defining anti-viral B cell repertoires. However, the Ig-cloning step is time-consuming and prevents high-throughput analysis of the B cell repertoire. Novel linear Ig heavy- and light-chain gene expression cassettes were designed to express Ig V(H) and V(L) genes isolated from sorted single B cells as IgG1 antibody without a cloning step. The cassettes contain all essential elements for transcriptional and translational regulation, including CMV promoter, Ig leader sequences, constant region of IgG1 heavy- or Ig light-chain, poly(A) tail and substitutable V(H) or V(L) genes. The utility of these Ig gene expression cassettes was established using synthetic V(H) or V(L) genes from an anti-HIV-1 gp41 mAb 2F5 as a model system, and validated further using V(H) and V(L) genes isolated from cloned EBV-transformed antibody-producing cell lines. Finally, this strategy was successfully used for rapid production of recombinant influenza mAbs from sorted single human plasmablasts after influenza vaccination. These Ig gene expression cassettes constitute a highly efficient strategy for rapid expression of Ig genes for high-throughput screening and analysis without cloning.
Article: A recombinant human immunodeficiency virus type 1 envelope glycoprotein complex stabilized by an intermolecular disulfide bond between the gp120 and gp41 subunits is an antigenic mimic of the trimeric virion-associated structure.[show abstract] [hide abstract]
ABSTRACT: The few antibodies that can potently neutralize human immunodeficiency virus type 1 (HIV-1) recognize the limited number of envelope glycoprotein epitopes exposed on infectious virions. These native envelope glycoprotein complexes comprise three gp120 subunits noncovalently and weakly associated with three gp41 moieties. The individual subunits induce neutralizing antibodies inefficiently but raise many nonneutralizing antibodies. Consequently, recombinant envelope glycoproteins do not elicit strong antiviral antibody responses, particularly against primary HIV-1 isolates. To try to develop recombinant proteins that are better antigenic mimics of the native envelope glycoprotein complex, we have introduced a disulfide bond between the C-terminal region of gp120 and the immunodominant segment of the gp41 ectodomain. The resulting gp140 protein is processed efficiently, producing a properly folded envelope glycoprotein complex. The association of gp120 with gp41 is now stabilized by the supplementary intermolecular disulfide bond, which forms with approximately 50% efficiency. The gp140 protein has antigenic properties which resemble those of the virion-associated complex. This type of gp140 protein may be worth evaluating for immunogenicity as a component of a multivalent HIV-1 vaccine.Journal of Virology 02/2000; 74(2):627-43. · 5.40 Impact Factor