Use of an anti‐CD16 antibody for in vivo depletion of natural killer cells in rhesus macaques

Abstract

Summary Non‐human primates serve as key animal models for a variety of viral infections. To evaluate the contribution of natural killer (NK) cells to the immune‐mediated control of these viruses in macaque monkeys, we have described a method for depleting NK cells in vivo by administration of anti‐human CD16 mouse monoclonal antibody. Using a fluorometric NK‐cell cytotoxicity assay, we show that most NK‐cell cytotoxicity in rhesus monkey peripheral blood mononuclear cells resides in the CD16+ and/or CD159A+ subset of lymphocytes. The anti‐human CD16 antibody, 3G8, binds to subsets of rhesus monkey lymphocytes and monocytes but not to neutrophils. Intravenous administration of 10–50 mg/kg of 3G8 to normal rhesus monkeys resulted in anti‐CD16 antibody persistence in the plasma for 1–3 weeks. This treatment also depleted 80–90% of CD3– CD159A+ lymphocytes, putative NK cells, from blood for at least 1 week and was associated with the loss of NK‐cell cytotoxicity when evaluated by in vitro assays. Using this method, transient depletion of NK cells from two rhesus monkeys chronically infected with simian immunodeficiency virus failed to cause changes in virus replication. These studies describe a non‐human primate model for in vivo NK‐cell depletion and suggest a limited role for cytotoxic CD16+ NK cells in controlling AIDS virus replication during chronic infection.

The FcγR of Humans and Non-human Primates and Their Interaction with IgG: Implications for Induction of Inflammation, Resistance to Infection and the Use of Therapeutic Monoclonal Antibodies

“…Analysis to date indicates that although macaque FccR expression is similar to human, key differences have been identified in pigtail macaque (Trist et al 2014) (Hogarth unpublished), in rhesus macaque (Rogers et al 2006;Choi et al 2008) and cynomolgus macaque (Table 1) (Warncke et al 2012). Flow cytometry shows FccRIIIa is present on macaque NK cells and monocytes (Webster and Johnson 2005;Choi et al 2008). FccRIIa is present on monocytes; macrophages, neutrophils and platelets; (Mahan et al 1993;Trist et al 2014;Warncke et al 2012) by PCR FccRIIb is present in B cells and classical CD14 + monocytes (Hogarth unpublished).…”

“…Analysis to date indicates that although macaque FccR expression is similar to human, key differences have been identified in pigtail macaque (Trist et al 2014) (Hogarth unpublished), in rhesus macaque (Rogers et al 2006;Choi et al 2008) and cynomolgus macaque (Table 1) (Warncke et al 2012). Flow cytometry shows FccRIIIa is present on macaque NK cells and monocytes (Webster and Johnson 2005;Choi et al 2008).…”

Increased Loss of CCR5+CD45RA−CD4+T Cells in CD8+Lymphocyte-Depleted Simian Immunodeficiency Virus-Infected Rhesus Monkeys

“…In addition to depleting CD8 ϩ T cells, the anti-CD8 MAb also eliminates other CD8 ϩ lymphocytes, such as NK cells. While the role of NK cells in controlling SIV replication remains unclear (15), emerging data suggest that they may play a significant role in HIV infection of humans (51). In addition to depletion of cell subsets other than CD8 ϩ T cells, CD8 ϩ lymphocyte depletion may also transiently increase the number of viral targets by nonspecific activation of CD4 ϩ T cells through release of enzymes/inflammatory mediators from dying cells or homeostatic mechanisms.…”

In Vivo Natural Killer Cell Depletion during Primary Simian Immunodeficiency Virus Infection in Rhesus Monkeys

“…The depleting activity of the mouse anti-CD16 activity is limited in duration by the emergence of anti-Ig antibodies, which we have shown to appear during the second week following antibody administration (3). In addition to a more-complete depletion of all subsets of NK cells, a longer duration of depletion that would be possible through the use of a recombinant anti-CD16 designed for use in primates would provide a more-rigorous evaluation of the role of NK cells in the SIV model.…”

“…We and others have used monoclonal antibodies to target and deplete T-or B-lymphocyte populations to define the contribution of cellular and humoral immunity to the control of SIV in monkeys (7,14,15). We recently developed and validated a nonhuman primate model of in vivo depletion of cytotoxic NK cells by antibody targeting of CD16 (3). Uniquely, the expression of CD16 on macaque monkey leukocytes is almost exclusively limited to a subset of lymphocytes and monocytes and is not expressed on neutrophils (13).…”