Reply to: Anti-CD4+ autoantibodies in immunological non-responder people with HIV: cause of CD4+ T-cell depletion?
Year: 2023
Type: letter
Abstract: 1] , and agree with the importance of this topic.The authors declare that autologous anti-CD4 IgG from immune non-responders (INRs) neither triggers CD4+ T cell death by antibodydependent cell cytotoxicity (ADCC) nor is responsible for CD4+ lymphocyte depletion in INRs.The main debate is whether anti-CD4 autoantibodies from INRs have an ADCC activitity.This paper showed several significant flaws in the Methodology.First, the isolation of antibodies with high-affinity is critical.The authors purified total but not high-affinity anti-CD4 autoantibodies [2] .HIV infection is associated with B cell polyclonal activation, thus, non-specific B cell responses may be included during anti-CD4 IgG isolation.In addition, the authors did not list the source of the human CD4 protein, which is of key importance for antibody purification from plasma and ADCC that require highly purified proteins to avoid non-specific effects.Furthermore, the plasma levels of anti-CD4 IgGs by ELISA were about 10-fold higher compared to the levels published [2] .It remains unknown if the results were due to non-specific binding, which may explain non-ADCC activities of isolated anti-CD4 IgGs.By contrast, the positive control zanolimumab had robust ADCC activity as there was no need for antibody purification.The authors show isolated anti-CD4 IgGs induced some cytokines from NK cells, however, NK-mediated cytoxicity can be induced through Fc-FcR interaction, which does not require the antigen binding region of antibodies.Therefore, it remains unknown whether the isolated anti-CD4 IgGs were truly the targeted autoantibodies against CD4.Next, we would like to share critical steps for the anti-CD4 IgG-mediated ADCC as this is a technically challenging assay [2] : 1) 2M Urea is added to each step of antibody isolation to obtain high-affinity antibodies; 2) CD4+ T cells are from PLWH; NK cells are isolated using fresh blood samples; 3) the concentration of anti-CD4 IgGs needs to be titrated and generally used at least 10-fold higher than that in the plasma.The authors used blood physiological concentrations of anti-CD4 IgGs, which probably was inadequate to expose this effect; and 4) when NK are co-cultured with CD4+ T cells, we recommend spinning the cells down in a V-bottom plate to allow tight interactions, which differs from the
Source: AIDS
Authors: Zhenwu Luo, Wei Jiang
Language: English
Topic: HIV Research and Treatment
Subfield: Virology
Field: Immunology and Microbiology
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W4317936546