|
14th International AIDS ConferenceBarcelona, Spain — July 7-12, 2002 |
Int Conf AIDS. 2002 Jul 7-12;14:Abstract No. MoOr1052
BACKGROUND: Discrimination between recent and established HIV-1 infection is necessary to measure infection incidence and correct interpretation of vaccine efficacy. The humoral immune response to HIV-1 was examined to identify markers to differentiate between early and late post-seroconversion periods.
METHODS: Affinity of the antibody was investigated using surface plasmon resonance (SPR). In sequential serum samples, antibody binding to: oligomeric gp41 (aa 530-653) and an immunodominant peptide of gp41, gp41579-613 was assessed.
RESULTS: Binding detected by SPR appeared to be due to antibodies of the IgG class. Antibody reactivity was seen by SPR at the same time in seroconversion panels as by screening EIAs. In all serum panels there was an increase in the affinity of both gp41- and gp41(579-613) -specific antibodies with time after infection. The miminum kd for the gp41579-613 peptide was consistently higher in all panels than that for the oligomeric protein. Maximal affinity was attained for the peptide within ~100 days post-infection, compared to at least 200 days for the protein. SPR was better able to detect small changes in affinity than conventional avidity assays using chaotropic agents in specific protein or peptide EIAs.
CONCLUSIONS: SPR detected polyclonal responses to HIV-1 reproducibly and was as sensitive in detecting antibody reactivity in seroconversion as EIAs. The affinity of sustained antibody responses to gp41 oligomer were greater than to the peptide corresponding to the immunodominant epitope. Alterations in antibody affinity to native HIV-1 proteins and peptides may provide a model for developing an HIV-1 incidence assay.
Presenting author: Elizabeth M. Dax
1National Serology Reference Laboratory, Australia, Fitzroy, Australia.
2St. Vincent's Institute of Medical Research, Fitzroy, Australia.
3Ludwig Cancer Institute, Parkville, Australia
4Centre for Immunology, St. Vincent's Hospital, Sydney, Australia.
020708
MoOrA1052
Copyright © 2002 - International AIDS Society (IAS). Reproduction of this abstract (other than one copy for personal reference) must be cleared through the IAS.
