The contribution of natural killer (NK) cells towards the immune containment of individual immunodeficiency virus infection remains undefined. SIV-induced central storage Compact disc4+ T-lymphocyte loss. These findings are consistent with a limited role for cytotoxic CD16+ NK cells in the control of primary SIV viremia. Natural killer (NK) cells are a Rabbit Polyclonal to U51 component of the innate immune system that plays a central role in host defense against viral infections and tumor cells. Much of the evidence for a role for NK cells in controlling viral infections has come from experiments with mice that were genetically altered (9) or treated with NK cell-depleting antibodies (8) or from the study of humans with inherited NK cell deficiencies (2, 11). The effect that NK cells may exert around the pathogenesis of human immunodeficiency computer virus (HIV) infection is usually less certain. A number of studies have indirectly implicated NK cells in affecting HIV replication or AIDS progression by potentially acting through the mechanisms of direct cytotoxicity, antibody-dependent cellular cytotoxicity, or the release of -chemokines (reviewed in reference 1). However, direct experimental evidence defining the contribution of NK cells to the control of HIV replication and AIDS is usually lacking. The simian immunodeficiency computer virus (SIV)-infected rhesus monkey is usually a powerful animal model for studying the immune control of HIV contamination. We as well as others possess utilized monoclonal antibodies to focus on and deplete T- or B-lymphocyte populations to define the contribution of mobile and humoral immunity towards the control of SIV in monkeys (7, 14, 15). We lately created and validated a non-human primate style of in vivo depletion of cytotoxic NK cells by antibody concentrating on of Compact disc16 (3). Exclusively, the appearance of Compact disc16 on macaque monkey leukocytes is nearly exclusively limited by a subset of lymphocytes and monocytes and isn’t portrayed on neutrophils (13). Compact disc16 is portrayed on nearly all bloodstream NK cells in rhesus macaques (17). Today’s research was initiated to research the function of NK cells in managing SIV during major infections. To explore the function of NK cells in the control of pathogen replication during major SIV infections in rhesus monkeys, we implemented an anti-human Compact disc16 monoclonal antibody clone 3G8 slowly; a murine immunoglobulin G() [IgG()] antibody with the intravenous path to five monkeys at a dosage of 50 mg/kg. Five extra rhesus monkeys received an equal dosage from the unimportant control mouse IgG() monoclonal antibody MOPC-21. 1 day after antibody administration, all monkeys were contaminated with uncloned SIVmac251 at a dosage equal to 6 intravenously.12 log10 SIV RNA copies. All monkeys had been harmful for the major histocompatibility complex class I allele Mamu-A*01 and were maintained in accordance with the guidelines of the Committee on Animals for 869363-13-3 the Harvard Medical School, federal and state laws, American Association for Accreditation of Laboratory Animal Care regulations, and the (9a). Changes in leukocyte subsets were monitored in EDTA-anticoagulated blood specimens obtained from these monkeys. Whole blood was incubated with anti-CD3 (SP34: BD Biosciences), anti-CD4 (L200; BD Biosciences), anti-CD16 (DJ130c, not cross-blocked by 3G8; DakoCytomation), anti-CD159A (NKG2A, Z199; Beckman 869363-13-3 Coulter), anti-CD8-alpha (SK1; BD Biosciences), anti-CD14 (M5E2; BD Biosciences), anti-CD28 (L293; BD Biosciences), and anti-CD95 (DX2; BD Biosciences) antibodies. Erythrocytes were then lysed using an ImmunoPrep system (Beckman Coulter), washed with phosphate-buffered saline, and resuspended in phosphate-buffered saline-1% formalin. Samples were analyzed using an LSRII flow cytometer (BD Biosciences), and data were reanalyzed using FlowJo software (Tree Star). Complete blood counts were performed on an automated hematology analyzer with rhesus-monkey-specific automated leukocyte differential software 869363-13-3 (ADVIA 120; Bayer). In animals that received the control antibody, the absolute number and percentage of peripheral blood NK cells, defined by immunophenotypic characterization as CD3? CD16+ CD159A+, remained stable or increased during primary SIV contamination (Fig. 1A and B, respectively). In contrast, animals that received the anti-CD16 antibody showed a sudden decline in the number and percentage of peripheral blood NK cells by day 1 following antibody treatment (Fig. 1A and B). At the point of maximum depletion, nearly 90% of NK cells were removed from the blood and the median number of NK cells remained less than 30% of baseline values through day 12. 869363-13-3 Anti-CD16 treatment also resulted in a 16 to 55% loss of CD16-bearing monocytes, whereas the monocyte numbers remained constant in the control antibody-treated group. Open up in another home window FIG. 1. Monoclonal anti-CD16 antibody (Ab) administration depleted NK cells from bloodstream during principal SIV infections. Rhesus monkeys had been implemented either anti-CD16 (crimson).