Five recombinant gp120s representing sequences of primary HIV-1 isolates from clade A, B and C (produced in 293 cells) and a p24 protein were purchased from Immune Technology Corp. (New York, NY). A set of 12 linear overlapping peptides (each 15mer with an 11 amino acid overlap or a 4 amino acid walk) corresponding to the sequence of consensus subtype-C V3 gp120 and CEF Control Peptide Pool (PP) (Cat. No. 9808) were obtained from the NIH AIDS Research and Reference Reagent Program (NIH, ARRRP). Two full length (35mer) peptides corresponding to the consensus-B (CTRPNNNTRKSIHIGPGRAFYTTGEIIG DIRQAHC) (V3B) and con-C (CTRPNNNTRKSIRI GPGQTFYATGDIIGDIRQAHC) (V3C) of V3 gp120, a 24mer con-C MPER (DLLALDSWKNLWNWFDITNW LWYIK) and a 19mer con-C IDR (LGIWGCSGKLICT TAVPWN) peptides of gp41 were selected from Los Alamos HIV-1 sequence database (http://hiv.lanl.gov), and were synthesized from Sigma Genosys, USA. The peptides were HPLC purified to >95% purity (based on information provided by company). The V3-cholera toxin B (CTB) fusion protein (V3C-CTB) and wild type CTB (WT-CTB) used for screening of antibody cultures were kindly provided by Prof. Susan Zolla Pazner from New York University School of Medicine.