There is much interest in the possible use of broadly neutralising antibodies (BNAbs) isolated from chronically infected HIV-1 patients to reduce the HIV-1 latent reservoir and to serve as a tool in vaccine design. However, the RV144 trial, the only HIV vaccine efficacy trial to date to show any protection, has highlighted the potential importance of non-neutralising antibodies and IgG subclass in HIV-1 control, whilst anti-HIV-1 antibodies from early infection have been less well characterised. The aims of this project were to generate monoclonal antibodies from longitudinal samples of an early HIV-1 infected patient in multiple IgG subclasses, and to analyse their characteristics and functions. Plasmablasts from an early HIV-1 infected patient at multiple time points were single cell sorted, and using molecular cloning techniques IgG1 monoclonal antibodies were isolated and tested for reactivity to HIV-1. Of 177 monoclonal antibodies, 2.82% were found to be HIV-1 specific. The distribution of heavy and light gene family usage was similar in HIV-1 specific and non-specific antibodies, whilst the number of nucleotide and amino acid mutations only increased over time in the non-specific antibodies. IgG1 expression vectors were modified to produce IgG2, IgG3, and IgG4 vectors, allowing patient derived anti-HIV-1 monoclonal antibodies and several well characterised BNABs to be generated in each of these subclasses. When tested using the RFADCC assay, one patient derived monoclonal antibody in the IgG1 and IgG3 subclasses, and one BNAb in the IgG3 subclass mediated weak ADCC activity.
Results have demonstrated that HIV-specific and non-specific antibodies isolated from early infection follow the same VH gene family usage trends, and that early infection anti-HIV IgG3 monoclonal antibodies may mediate weak ADCC activity. Furthermore, the IgG2-4 expression vectors now allow the rapid generation of antibodies in multiple subclasses, and may have the potential to generate more potent therapeutic monoclonal antibodies.