Phagocytic Ability Of Macrophages Research Articles

Study on the material basis and immunological enhancement activity of dangdi oral liquid

Studies have shown that a lot of traditional Chinese medicines could improve the immunity of the body. Dangdi oral liquid (DDO) was mainly composed of Angelica sinensis (Oliv.) Diels (Danggui), Rehmannia glutinosa Libosch. (Dihuang), Achyranthes bidentata Bl. (Niuxi), Glycyrrhiza uralensis Fisch. (Gancao). In this study, the rapid ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS) method was used to identify the potentially effective compounds of DDO. Then the immune activity of DDO was measured by lymphocyte proliferation, macrophage phagocytic function, NK cell activity, delayed type hypersensitivity reaction, hemolytic plaque number, sIgA content and immune organ index. The results showed that a total of 51 compounds were identified. In addition, DDO could significantly promote the lymphocyte proliferation, improve macrophage phagocytic ability, NK cell activity, hemolytic plaque number, sIgA content and immune organ index compared with control group, and the medium dose possessed the best efficacy (P＜0.05). These results indicated that DDO could enhance the immunity of mice.

Upregulation of GPR133 expression impaired the phagocytosis of macrophages in recurrent spontaneous miscarriage

ABSTRACT Decidual macrophages are the second-largest immune cell group at the maternal-foetal interface. They participate in apoptotic cell removal, and protect the foetus from microorganisms or pathogens. Dysfunction of decidual macrophages gives rise to pregnancy complications such as preeclampsia and recurrent spontaneous miscarriage (RSM). However, the mechanisms by which decidual macrophages are involved in the occurrence of adverse pregnancy outcomes have not been elucidated. Here we integrated DNA methylation and gene expression data from decidua macrophages to identify potential risk factors related to RSM. GPR133 was significantly hypomethylated and upregulated in decidual macrophages from RSM patients. Further demethylation analysis demonstrated that GPR133 expression in decidual macrophages was significantly increased by 5-Aza-dC treatment. In addition, the influence of GPR133 on the phagocytic ability of macrophages was explored. Phagocytosis was impaired in the decidual macrophages of RSM patients with increased GPR133 expression. Increased GPR133 expression induced by demethylation treatment in the decidual macrophages of healthy control patients led to a significant decrease in phagocytic function. Importantly, knockdown of GPR133 resulted in a significant improvement in the phagocytic function of THP-1 macrophages. In conclusion, the existing studies have shown the influence of GPR133 on the phagocytic function of decidual macrophages and pregnancy outcomes, providing new data and ideas for future research on the role of decidual macrophages in RSM.

Early-wave macrophages control late hematopoiesis

Macrophages constitute the first defense line against the non-self, but their ability to remodel their environment in organ development/homeostasis is starting to be appreciated. Early-wave macrophages (EMs), produced from hematopoietic stem cell (HSC)-independent progenitors, seed the mammalian fetal liver niche wherein HSCs expand and differentiate. The involvement of niche defects in myeloid malignancies led us to identify the cues controlling HSCs. In Drosophila, HSC-independent EMs also colonize the larva when late hematopoiesis occurs. The evolutionarily conserved immune system allowed us to investigate whether/how EMs modulate late hematopoiesis in two models. We show that loss of EMs in Drosophila and mice accelerates late hematopoiesis, which does not correlate with inflammation and does not rely on macrophage phagocytic ability. Rather, EM-derived extracellular matrix components underlie late hematopoiesis acceleration. This demonstrates a developmental role for EMs.

The Effect of Aspirin and Ibuprofen on the Phagocytic Ability of Macrophages

The Effect of Aspirin and Ibuprofen on the Phagocytic Ability of Macrophages

The Effect of Aspirin and Ibuprofen on the Phagocytic Ability of Macrophages

The Effect of Aspirin and Ibuprofen on the Phagocytic Ability of Macrophages

Geniposide ameliorates acute kidney injury via enhancing the phagocytic ability of macrophages towards neutrophil extracellular traps

Acute kidney injury (AKI) is a clinically serious disorder associated with high mortality rates and an increased risk of progression to end-stage renal disease. As an essential supportive treatment for patients with respiratory failure, mechanical ventilation not only save many critically ill patients, but also affect glomerular filtration function by changing renal hemodynamics, neurohumoral and positive end-expiratory pressure, eventually leading to AKI. AMP-activated protein kinase (AMPK), a crucial energy homeostasis regulator, could enhance macrophage phagocytic ability and inhibit inflammation, but whether it can engulf neutrophil extracellular traps (NETs) and alleviate mechanical ventilation-associated AKI is still unclear. In this study, we found that geniposide significantly ameliorated histopathological damage, reduced serum Cre and BUN levels. Besides, geniposide can also induce AMPK activation and enhance macrophage phagocytic ability toward NETs. Moreover, geniposide can markedly reduce the levels of high mobility group box 1 (HMGB1), and these effects were dependent on AMPK-PI3K/Akt signaling. Altogether, these results indicated that geniposide promoted macrophage efferocytosis by inducing AMPK-PI3K/Akt signaling activation, clearing NETs and ameliorating AKI.

Phagocytosis of LM-Mel-45 Melanoma and Jurkat Cells by THP-1 Macrophages

Exposing macrophages to IFN-g or IL-4 polarizes them toward M1-like inflammatory or M2-like tissue repair phenotypes, respectively. It is uncertain whether the macrophage phenotypes are equally effective at phagocytosing melanoma and non-melanoma bait cells. We hypothesize that phenotypic polarization of macrophages will improve their phagocytic ability and that phagocytic vulnerability will depend on bait cell type. This study compares phenotypic polarization of macrophages on phagocytosis of LM-Mel-45 (LM45) melanoma cells and non-melanoma (Jurkat) cells at 2 h or 16 h. Macrophage differentiation to an M0 phenotype was induced by exposing THP-1 monocytes to 50 ng/ml PMA for two days, followed by 4 days rest in RPMI 1640, 10% FBS. M1-like and M2-like phenotypes were induced by 24 h exposure to 20 ng/ml IFN-γ and 20 ng/mL IL-4, respectively. Phenotypic state was measured by surface expression of CCR7, CD209, and CD172. Bait cells (LM45 or Jurkat) were treated with 0.5 mM staurosporine for 24 h to induce apoptosis and stained with CellTrace® Violet. Macrophages were stained with CellTracker® Orange CMRA. Bait cells were added to adherent macrophages to measure phagocytosis (2 or 16 h). To qualitatively monitor the phagocytic process, time-lapse imaging every 15 min for 16 h was done on a Zeiss Axiovert 200M microscope with a 10x objective. To quantify phagocytosis, adhered and loose cells were harvested and prepared for flow cytometry. Cells were analyzed for violet, orange, or both orange and violet staining. Positive phagocytosis was expressed as the percentage of orange macrophages with violet staining above the violet cutoff. M0 macrophages are positive for CD172. Exposure to IFN-γ increases levels of CD209 and CCR7, and CD172 remains present. Exposure to IL-4 increases levels of CD209 with little change in CCR7 and CD172 remains present. Time-lapse imaging shows phagocytosis of LM45 cells via a “nipping” behavior rather than engulfment. When Jurkat cells serve as bait, multiple bait cells will attach to a single macrophage. Blebbing in bait cells is seen by 8 h. Phagocytic rate toward LM45 cells over 2 h averaged 6.7 ± 1.8% for M0 macrophages and 5.6 ± 2.3% for IFN-γ treated macrophages. Phagocytic rate toward LM45 cells over 16 h averaged 13.9 ± 1.3% for M0 macrophages and 14.9 ± 1.8% for IFN-γ treated macrophages. The differences were not significant. Phagocytic rate toward Jurkat cells averaged 22.4 ± 3.5% for M0 macrophages and 26.9 ± 4.0% for IFN-γ treated macrophages. This difference was not significant. Phagocytosis was significantly greater for Jurkat cells than LM45 cells (P<0.001). In summary, IFN-γ treatment does not increase macrophage phagocytic ability, refuting our hypothesis. However, macrophages phagocytose Jurkat cells more effectively than LM45 melanoma, suggesting that chemotherapy designed to increase phagocytic vulnerability may have potential in melanoma treatment. KCOM Graduate Program Grant #851-068 This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Probiotic-based nanoparticles for targeted microbiota modulation and immune restoration in bacterial pneumonia.

While conventional bacterial pneumonia mainly centralizes avoidance of bacterial colonization, it remains unclear how to restore the host immunity for hyperactive immunocompetent primary and immunocompromised secondary bacterial pneumonia. Here, probiotic-based nanoparticles of OASCLR were formed by coating chitosan, hyaluronic acid and ononin on living Lactobacillus rhamnosus. OASCLR nanoparticles could effectively kill various clinic common pathogens and antibacterial efficiency was >99.97%. Importantly, OASCLR could modulate lung microbiota, increasing the overall richness and diversity of microbiota by decreasing pathogens and increasing probiotic and commensal bacteria. Additionally, OASCLR could target inflammatory macrophages by the interaction of OASCLR with the macrophage binding site of CD44 and alleviate overactive immune responses for hyperactive immunocompetent pneumonia. Surprisingly, OASCLR could break the state of the macrophage's poor phagocytic ability by upregulating the expression of the extracellular matrix assembly, immune activation and fibroblast activation in immunocompromised pneumonia. The macrophage's phagocytic ability was increased from 2.61% to 12.3%. Our work provides a potential strategy for hyperactive immunocompetent primary and immunocompromised secondary bacterial pneumonia.

Effect of velvet antler on the immune activity of cyclophosphamide-induced immunosuppressed mice

ABSTRACT To study the antioxidant and immune protection activity of velvet antler (VA) in cyclophosphamide-induced immunocompromised mice, BALB/c mice were intragastrically administered 100, 300, or 500 mg/(kg·d) VA for 30 days, and were intraabdominally injected with cyclophosphamide to create a hypoimmune murine model. Cellular immunity, macrophage phagocytic activity, natural killer (NK) cell activity, white blood cell count, splenic lymphocyte subsets and the mRNA expression levels of serum cytokines were analysed. We found that the IC50 for removing 2,2'-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS), OH, and 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radicals of VA were 0.476, 4.33, and 37.92 mg/mL, respectively. VA could enhance innate and adaptive immunity of mice by improving cellular immunity, macrophage phagocytic ability, and NK cell activity; promoting the production of IL-4, IFN-γ, TNF-α and other cytokines; increasing the content and ratio of lymphocyte subsets. These results indicate that VA has good antioxidant activity and can improve the immune function of cyclophosphamide-induced immunodeficient mice.

Tyrosine phosphorylation tunes chemical and thermal sensitivity of TRPV2 ion channel.

Transient receptor potential vanilloid 2 (TRPV2) is a multimodal ion channel implicated in diverse physiopathological processes. Its important involvement in immune responses has been suggested such as in the macrophages' phagocytosis process. However, the endogenous signaling cascades controlling the gating of TRPV2 remain to be understood. Here, we report that enhancing tyrosine phosphorylation remarkably alters the chemical and thermal sensitivities of TRPV2 endogenously expressed in rat bone marrow-derived macrophages and dorsal root ganglia (DRG) neurons. We identify that the protein tyrosine kinase JAK1 mediates TRPV2 phosphorylation at the molecular sites Tyr(335), Tyr(471), and Tyr(525). JAK1 phosphorylation is required for maintaining TRPV2 activity and the phagocytic ability of macrophages. We further show that TRPV2 phosphorylation is dynamically balanced by protein tyrosine phosphatase non-receptor type 1 (PTPN1). PTPN1 inhibition increases TRPV2 phosphorylation, further reducing the activation temperature threshold. Our data thus unveil an intrinsic mechanism where the phosphorylation/dephosphorylation dynamic balance sets the basal chemical and thermal sensitivity of TRPV2. Targeting this pathway will aid therapeutic interventions in physiopathological contexts.

Promoting antibody-dependent cellular phagocytosis for effective macrophage-based cancer immunotherapy.

Macrophages are essential in eliciting antibody-dependent cellular phagocytosis (ADCP) of cancer cells. However, a satisfactory anticancer efficacy of ADCP is contingent on early antibody administration, and resistance develops along with cancer progression. Here, we investigate the mechanisms underlying ADCP and demonstrate an effective combinatorial strategy to potentiate its efficacy. We identified paclitaxel as a universal adjuvant that efficiently potentiated ADCP by a variety of anticancer antibodies in multiple cancers. Rather than eliciting cytotoxicity on cancer cells, paclitaxel polarized macrophages toward a state with enhanced phagocytic ability. Paclitaxel-treated macrophages down-regulated cell surface CSF1R whose expression was negatively correlated with patient survival in multiple malignancies. The suppression of CSF1R in macrophages enhanced ADCP of cancer cells, suggesting a role of CSF1R in regulating macrophage phagocytic ability. Together, these findings define a potent strategy for using conventional anticancer drugs to stimulate macrophage phagocytosis and promote the therapeutic efficacy of clinical anticancer antibodies.

CCAAT/enhancer binding protein (C/EBP) delta promotes the expression of PTX3 and macrophage phagocytosis during A. fumigatus infection.

Given the increasing incidence of pulmonary aspergillosis, it is important to understand the natural defense mechanisms by which the body can kill Aspergillus fumigatus conidia. Pentraxin 3 (PTX3) plays a nonredundant role in resistance to A. fumigatus. Here, we found that the key predicted PTX3 transcription factor, CCAAT/enhancer-binding protein δ (CEBPD), was up-regulated during A. fumigatus conidia infection. Functionally, CEBPD significantly promoted the expression of PTX3 and the phagocytic ability of macrophages. Mechanistically, CEBPD activated the PTX3 by directly binding to the promoter region of the PTX3 gene. We also showed that the RNA-binding protein human antigen R promoted CEBPD expression. These findings provide new insights into the crucial role of CEBPD in the phagocytosis of A. fumigatus conidia by macrophages and highlight this protein as a potential therapeutic target for invasive pulmonary aspergillosis.

CX3CR1 But Not CCR2 Expression Is Required for the Development of Autoimmune Peripheral Neuropathy in Mice.

One hallmark of Guillain-Barre syndrome (GBS), a prototypic autoimmune peripheral neuropathy (APN) is infiltration of leukocytes (macrophages and T cells) into peripheral nerves, where chemokines and their receptors play major roles. In this study, we aimed to understand the potential contribution of chemokine receptors CCR2 and CX3CR1 in APN by using a well-established mouse model, B7.2 transgenic (L31) mice, which possesses a predisposed inflammatory background. We crossbred respectively CCR2KO and CX3CR1KO mice with L31 mice. The disease was initiated by partial ligation on one of the sciatic nerves. APN pathology and neurological function were evaluated on the other non-ligated sciatic nerve/limb. Our results revealed that L31/CX3CR1KO but not L31/CCR2KO mice were resistant to APN. CX3CR1 is needed for maintaining circulating monocyte and CD8+ T cell survival. While migration of a significant number of activated CD8+ T cells to peripheral nerves is essential in autoimmune response in nerve, recruitment of monocytes into PNS seems optional. Disease onset is independent of CCR2 mediated blood-derived macrophage recruitment, which can be replaced by compensatory proliferation of resident macrophages in peripheral nerve. CX3CR1 could also contribute to APN via its critical involvement in maintaining nerve macrophage phagocytic ability. We conclude that blockade of CX3CR1 signaling may represent an interesting anti-inflammatory strategy to improve therapeutic management for GBS patients.

A dual macrophage polarizer conjugate for synergistic melanoma therapy

Tumor associated macrophages (TAMs) play a paradoxical role in the fate of aggressive tumors like melanoma. Immune modulation of TAMs from the tumor-permissive M2 phenotype to antitumoral M1 phenotype is an emerging attractive approach in melanoma therapy. Resiquimod is a TLR7/8 agonist that shifts the polarization of macrophages towards M1 phenotype. Bexarotene (BEX) is a retinoid that induce the expression of phagocytic receptors in macrophages besides its ability to downregulate the M2 polarization. However, the clinical use of both agents is hindered by poor pharmacokinetic properties. Here, for the first time we repurposed BEX based on its immunomodulatory properties and combined it with RES by designing hyaluronic acid (HA) conjugates of both drugs that act synergistically as a dual macrophage polarizer to promote the M1 phenotype and suppress the M2 phenotype. This combination enhanced the macrophage secretion of proinflammatory cytokines (IL-6 and TNF-α), while suppressing the production of tumor promoting cytokine CCL22. It enhanced the macrophage phagocytic ability and showed superior inhibitory effects against B16F10 cells. In vivo studies on a mouse melanoma model confirmed the superiority of the dual conjugate compared to the single HA-drug conjugates in suppressing the tumor growth. Immunoprofiling of the excised tumors revealed a significant increase in the M1/M2 ratio of TAMs in mice treated with the dual conjugate. Our intravenously injectable HA conjugate of RES and BEX provides a promising immunotherapeutic combination strategy for resetting the M1/M2 ratio, supporting the tumoricidal activity of TAMs for effective melanoma treatment.

Content and composition analysis of polysaccharides fromBlaps rynchopeteraand its macrophage phagocytic activity

AbstractBlaps rynchopeteraFairmaire has a long history of use as a folk medicine in China for treating fever, cough, gastritis, boils, and tumors. In the present study, the content analyses, monosaccharide composition analyses, and the macrophage phagocytic activity ofrynchopeterapolysaccharides (RPS) were reported.B. rhynchopterais rich in polysaccharides (content value 3.97%). Through PMP (1-phenyl-3-methyl-5-pyrazolone) pre-column derivatization and high performance liquid chromatography (HPLC) testing, the results showed that RPS consist of 8 known monosaccharides, including D-mannose (Man), Rhamnose (Rha), D-glucuronic acid (GlcUA), D-galacturonic acid (GalUA), D-glucose (Glc), D-galactose (Gal), Arabinose (Ara), and Fucose (Fuc), with the total content of 171.70 mg g−1and Glc has the highest content of 45.40 mg g−1. The phagocytic ability of mouse peritoneal macrophages was investigated after RPS stimulating alone and combined with lipopolysaccharide (LPS). RPS played an important role in the engulfment of mouse peritoneal macrophages and can significantly enhance the phagocytic ability of macrophages. However, no synergistic effects were observed when RPS combined with LPS.

Warburg Effect Is a Cancer Immune Evasion Mechanism Against Macrophage Immunosurveillance.

Evasion of immunosurveillance is critical for cancer initiation and development. The expression of “don’t eat me” signals protects cancer cells from being phagocytosed by macrophages, and the blockade of such signals demonstrates therapeutic potential by restoring the susceptibility of cancer cells to macrophage-mediated phagocytosis. However, whether additional self-protective mechanisms play a role against macrophage surveillance remains unexplored. Here, we derived a macrophage-resistant cancer model from cells deficient in the expression of CD47, a major “don’t eat me” signal, via a macrophage selection assay. Comparative studies performed between the parental and resistant cells identified self-protective traits independent of CD47, which were examined with both pharmacological or genetic approaches in in vitro phagocytosis assays and in vivo tumor models for their roles in protecting against macrophage surveillance. Here we demonstrated that extracellular acidification resulting from glycolysis in cancer cells protected them against macrophage-mediated phagocytosis. The acidic tumor microenvironment resulted in direct inhibition of macrophage phagocytic ability and recruitment of weakly phagocytic macrophages. Targeting V-ATPase which transports excessive protons in cancer cells to acidify extracellular medium elicited a pro-phagocytic microenvironment with an increased ratio of M1-/M2-like macrophage populations, therefore inhibiting tumor development and metastasis. In addition, blockade of extracellular acidification enhanced cell surface exposure of CD71, targeting which by antibodies promoted cancer cell phagocytosis. Our results reveal that extracellular acidification due to the Warburg effect confers immune evasion ability on cancer cells. This previously unrecognized role highlights the components mediating the Warburg effect as potential targets for new immunotherapy harnessing the tumoricidal capabilities of macrophages.

The Neuroimmunology of Guillain-Barré Syndrome and the Potential Role of an Aging Immune System.

Guillain-Barré syndrome (GBS) is a paralyzing autoimmune condition affecting the peripheral nervous system (PNS). Within GBS there are several variants affecting different aspects of the peripheral nerve. In general, there appears to be a role for T cells, macrophages, B cells, and complement in initiating and perpetuating attacks on gangliosides of Schwann cells and axons. Of note, GBS has an increased prevalence and severity with increasing age. In addition, there are alterations in immune cell functioning that may play a role in differences in GBS with age alongside general age-related declines in reparative processes (e.g., delayed de-differentiation of Schwann cells and decline in phagocytic ability of macrophages). The present review will explore the immune response in GBS as well as in animal models of several variants of the disorder. In addition, the potential involvement of an aging immune system in contributing to the increased prevalence and severity of GBS with age will be theorized.

ERK Modulates Macrophage Polarization and Alters Exosome miRNA Expression in Diabetic Nephropathy.

The aim is to probe into the differential expression of miRNA in macrophage exosomes in diabetic nephropathy (DN) by ERK regulating macrophage polarization through the NF-κB/JAK-STAT signaling pathway. Our team cultivated the mouse macrophage line RAW264 cells. When the cell growth status was good, we added 30 mmol/L glucose, and then added ERK/JAK-STAT/NF-κB inhibitors separately. We adopted western blot for observing macrophage polarization and the impact of JAK-STAT inhibitor on caspase-9, eNOS, NF-κB p65 expression, extracted exosomes, and total exosome RNA of each group of cells. Their miRNA expression profiles were also analyzed by high-throughput sequencing. (1) In comparison with the control group, relative iNOS protein expression in ERK inhibitor group dramatically declined (p < 0.05), and the iNOS protein content in the NF-κB inhibitor group and the JAK-STAT inhibitor group conspicuously dwindled (p < 0.05); relative CD206 protein expression in each inhibitor group was clearly augmented (p > 0.05). Under the intervention of high glucose, ERK/JAK-STAT/NF-κB inhibitors brilliantly diminished the up-regulation of caspase-9 (p < 0.05), and ERK/JAK-STAT inhibitors notably minimized the up-regulation of NF-κB p65 (p < 0.05). ELISA results unveiled that in contrast to the control group, TNF-α, IL-1β, and CXCL10 levels in the macrophage supernatant of the inhibitor group was tellingly augmented (p < 0.05), whereas TGF-β level had strikingly declined (p < 0.05), proving that macrophages were activated to M1. (2) Flow cytometry uncloaked that the phagocytic ability of macrophages in inhibitor group was compellingly lower than that in the control group. (3) One hundred thirty-six known miRNAs with notably differential expression and 5,134 miRNA sequences were detected in the exosomes of the macrophage supernatant of each experimental group. Of those, some differentially expressed miRNAs include miR-193a-3p, miR-1260B, and miR-3175. miR-193a-3p, miR-1260B, and miR-3175 extensively participate in the development of cancer, arthritis, osteogenic differentiation, Alzheimer's disease, and other diseases, as well as in the regulation of MAPK/ERK, TLR4/NF-κB, and other signaling pathways. ERK modulates macrophage activation to M1 and alters exosome miRNA expression profile via NF-κB/JAK-STAT pathway.

Perfluorooctanoic acid (PFOA) exposure induces splenic atrophy via overactivation of macrophages in male mice

Perfluorooctanoic acid (PFOA), a synthetic and widely used chemical, has aroused wide public concern due to its persistence, bioaccumulation, and potential toxicity. To investigate splenic atrophy induced by PFOA, male mice were exposed to 0, 0.4, 2, or 10 mg/kg/d PFOA for 28 d. Results demonstrated that spleen weight and relative spleen weight (RSW) decreased in the 2 and 10 mg/kg/d PFOA exposure groups. Iron levels in the spleen and serum were also reduced in all PFOA exposure groups. Weighted gene co-expression network analysis (WGCNA) of 7 043 genes highlighted enrichment in cell cycle, autoimmunity, and anemia in the spleen. In addition, changes in the levels of hemoglobin, platelets, bilirubin, and heme oxygenase-1 were consistent with anemia. The ratio of total macrophages to M1 macrophages in the spleen, phagocytic ability of macrophages, and levels of cytokines such as TNF-α, IL-1β, and IL-6 all increased, thus suggesting the occurrence of autoimmune disorder. Therefore, we concluded that overactivation of macrophages may be an important reason for splenic atrophy induced by PFOA exposure.

Abundance of Non-Polarized Lung Macrophages with Poor Phagocytic Function in Chronic Obstructive Pulmonary Disease (COPD).

Lung macrophages are the key immune effector cells in the pathogenesis of Chronic Obstructive Pulmonary Disease (COPD). Several studies have shown an increase in their numbers in bronchoalveolar lavage fluid (BAL) of subjects with COPD compared to controls, suggesting a pathogenic role in disease initiation and progression. Although reduced lung macrophage phagocytic ability has been previously shown in COPD, the relationship between lung macrophages’ phenotypic characteristics and functional properties in COPD is still unclear. (1) Methods: Macrophages harvested from bronchoalveolar lavage (BAL) fluid of subjects with and without COPD (GOLD grades, I–III) were immuno-phenotyped, and their function and gene expression profiles were assessed using targeted assays. (2) Results: BAL macrophages from 18 COPD and 10 (non-COPD) control subjects were evaluated. The majority of macrophages from COPD subjects were non-polarized (negative for both M1 and M2 markers; 77.9%) in contrast to controls (23.9%; p < 0.001). The percentages of these non-polarized macrophages strongly correlated with the severity of COPD (p = 0.006) and current smoking status (p = 0.008). Non-polarized macrophages demonstrated poor phagocytic function in both the control (p = 0.02) and COPD (p < 0.001) subjects. Non-polarized macrophages demonstrated impaired ability to phagocytose Staphylococcus aureus (p < 0.001). They also demonstrated reduced gene expression for CD163, CD40, CCL13 and C1QA&B, which are involved in pathogen recognition and processing and showed an increased gene expression for CXCR4, RAF1, amphiregulin and MAP3K5, which are all involved in promoting the inflammatory response. (3) Conclusions: COPD is associated with an abundance of non-polarized airway macrophages that is related to the severity of COPD. These non-polarized macrophages are predominantly responsible for the poor phagocytic capacity of lung macrophages in COPD, having reduced capacity for pathogen recognition and processing. This could be a key risk factor for COPD exacerbation and could contribute to disease progression.