Serum anti‐p24 antibody concentration has a predictive value on the decrease of CD4 lymphocyte count higher than acid‐dissociated p24 antigen

Abstract

We studied the prognostic value on the decrease of CD4 lymphocyte count of anti-p24 antibody (ab) titer and compared this value with that of polyclonal and monoclonal p24 (ag) titer before and after immune complex dissociation (ICD); 53 human immunodeficiency virus (HIV)-infected patients having CD4+ counts above 400/mm3 when first examined were followed up over a 3-year period including at least four visits; HIV disease progressors (n = 18) were defined as having CD4+ counts below 200/mm3 and non-progressors (n = 35) as having CD4+ counts still above 400/mm3 at the end of follow-up. Sera were collected at each visit and assayed for p24 ag with and without ICD and for anti-p24 ab titer. The mean anti-p24 ab titer of progressors and of non-progressors at entry was significantly different. A threshold of anti-p24 ab titer indicating a HIV progression was determined at 1/300. The proportion of individuals with an anti-p24 ab titer lower than 1/300 at least once during the study period was 34% in non-progressors and 94% in progressors. The difference between progressors and non-progressors at entry was significant with monoclonal p24 ag without ICD and more significant with monoclonal p24 ag after ICD. The marker having the highest predictive value was the anti-p24 ab titer, then monoclonal p24 ag with ICD, then polyclonal p24 ag with ICD. Anti-p24 ab is an earlier and stronger marker of the decrease of CD4 lymphocyte count than p24 ag even after ICD.

Isotype Diversification of IgG Antibodies to HIV Gag Proteins as a Therapeutic Vaccination Strategy for HIV Infection

“…Approximately one third of HIV-1 controllers do not exhibit evidence of HLA-B-restricted CD8 + T-cell responses against Gag proteins [ 12 ], suggesting that other immune responses also contribute to natural control of HIV-1 infection. At least 15 published studies undertaken between 1989 and 2000 in untreated HIV-1-infected adults and children who were not selected on the basis of a controller phenotype, demonstrated that progression of HIV-1 disease was slower in patients with higher serum levels and/or avidity of IgG antibodies to HIV-1 Gag proteins (p17, p24, p55) [ 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 ], suggesting that HIV-1 Gag proteins might be used as vaccine immunogens for eliciting antibodies to control HIV-1 infection. HIV-1 Gag proteins might have the particular advantage of exhibiting high intra-clade and inter-clade epitope conservation, at least for T-cell epitopes [ 30 ], and might thereby elicit broadly reactive antibodies.…”