Evaluation of monoclonal antibodies to HIV-1 envelope by neutralization and binding assays: an international collaboration.
OBJECTIVE
To characterize a purified panel of monoclonal antibodies (MAb) to epitopes in HIV-1 envelope V3, CD4-binding region, C4 and gp41.


METHODS
Neutralization and/or binding activity data were obtained from 21 laboratories on a coded panel consisting of seven human MAb, seven mouse MAb, recombinant human CD4 immunoadhesin [CD4-immunoglobulin G (IgG)], normal human and normal murine Ig.


METHODS
Laboratories performed a variety of neutralization assays and antigen binding assays with HIVIIIB, HIVMN and other laboratory strains of HIV-1.


RESULTS
For a single MAb, there was up to a 10(3) range of neutralizing antibody titers between laboratories. The range in titers appeared to depend on the sensitivity of the neutralization assay. Two methods were used to consolidate the data from all laboratories, the geometric mean titer (GMT) and the median neutralizing titer (MNT). The panel of MAb were also analyzed by a variety of assays that measure binding activity to native or denatured epitopes. The relative binding activity of the MAb did not appear to correlate with neutralizing activity.


CONCLUSIONS
Neutralization results from any single laboratory did not correlate with the collective data. The relative potency (rank order) of the MAb in the panel were equivalent when determined by GMT or MNT. These values may be useful to individual laboratories for estimating the sensitivity of their neutralization assays. The study also identified potential reference reagents with which neutralizing activity could be compared.
D'Souza
M P
MP
Division of AIDS, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892.
Geyer
S J
SJ
Hanson
C V
CV
Hendry
R M
RM
Milman
G
G
D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000937:Antigen-Antibody Reactions; D001665:Binding Sites; D015704:CD4 Antigens / Q000378:metabolism; D016466:CHO Cells; D006224:Cricetinae; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000737:chemistry / Q000276:immunology / Q000378:metabolism; D015686:Gene Products, env / Q000276:immunology / Q000378:metabolism; D015483:HIV Antibodies / Q000276:immunology* / Q000378:metabolism; D015488:HIV Antigens / Q000276:immunology* / Q000378:metabolism; D015699:HIV Envelope Protein gp120 / Q000276:immunology / Q000378:metabolism; D019302:HIV Envelope Protein gp160; D015700:HIV Envelope Protein gp41 / Q000276:immunology / Q000378:metabolism; D015497:HIV-1 / Q000276:immunology*; D006801:Humans; D007391:International Cooperation; D051379:Mice; D008969:Molecular Sequence Data; D009500:Neutralization Tests; D010446:Peptide Fragments / Q000276:immunology / Q000378:metabolism; D011485:Protein Binding; D011498:Protein Precursors / Q000276:immunology / Q000378:metabolism; D011994:Recombinant Proteins / Q000276:immunology / Q000378:metabolism; D012015:Reference Standards; D015203:Reproducibility of Results; D012441:Saccharomyces cerevisiae; D012680:Sensitivity and Specificity
D000911:Antibodies, Monoclonal; D015704:CD4 Antigens; D000939:Epitopes; D015686:Gene Products, env; D015483:HIV Antibodies; D015488:HIV Antigens; D015699:HIV Envelope Protein gp120; D019302:HIV Envelope Protein gp160; D015700:HIV Envelope Protein gp41; C059762:HIV envelope protein gp120 (305-321); D010446:Peptide Fragments; D011498:Protein Precursors; D011994:Recombinant Proteins