Abstract: Partially occluded and/or multimeric presentations of peptides mimic the epitopes recognised by antibodies capable of neutralising diverse clinical isolates of the human immunodeficiency virus type 1 (HIV-1). By “partially occluded” is meant a presentation that has a three-dimensional structure (probably a barrel/cylindrical/helical shape) generated by inter-chain disulphide bridging or other means that has internally, at or near its base, the epitope that is recognised by the neutralising antibody; i.e. a partially occluded presentation is a three-dimensional presentation of one or more neutralising epitopes such that the epitope is located in a pocket or cleft. Such presentations are better at eliciting antibodies that have the neutralising phenotype, and may be used as vaccines or to produce antibodies for the prevention or treatment of HIV-1 infection.