Inhibition of macrophage-mediated phagocytosis has emerged as an essential mechanism for tumor immune evasion. One mechanism inhibiting the innate response is the presence of the macrophage inhibitory molecule, signal regulatory protein-α (SIRPα), on tumor-associated macrophages (TAMs) and its cognate ligand cluster of differentiation 47 (CD47) on tumor cells in the tumor microenvironment. On the basis of a recently discovered programmed death protein 1 (PD-1) in TAMs, we discuss the potential inhibitory receptors that possess new functions beyond T cell exhaustion in this review. As more and more immune receptors are found to be expressed on TAMs, the corresponding therapies may also stimulate macrophages for phagocytosis and thereby provide extra anti-tumor benefits in cancer therapy. Therefore, identification of biomarkers and combinatorial therapeutic strategies, have the potential to improve the efficacy and safety profiles of current immunotherapies.
Antigens, Surface ; metabolism ; Apoptosis Regulatory Proteins ; metabolism ; Humans ; Immunotherapy ; methods ; Macrophages ; immunology ; Neoplasms ; immunology ; pathology ; therapy ; Phagocytosis ; immunology ; Treatment Outcome ; Tumor Microenvironment ; immunology

No abstract available.
Asian Continental Ancestry Group/*genetics ; Base Sequence ; Bone Marrow Cells/cytology/pathology ; Cytomegalovirus Infections/diagnosis ; Epstein-Barr Virus Infections/diagnosis ; Female ; Flow Cytometry ; Heterozygote ; Humans ; Infant ; Killer Cells, Natural/cytology/immunology ; Lymphohistiocytosis, Hemophagocytic/*diagnosis/genetics ; Perforin/*genetics ; Phagocytosis ; Polymorphism, Single Nucleotide ; Republic of Korea ; Sequence Analysis, DNA

Lipooligosacharide (LOS) of Neisseria gonorrhoeae (gonococci, GC) is involved in the interaction of GC with host cells. Deletion of the alpha-oligosaccharide (alpha-OS) moiety of LOS (lgtF mutant) significantly impairs invasion of GC into epithelial cell lines. GC opacity (Opa) proteins, such as OpaI, mediate phagocytosis and stimulate chemiluminescence responses in neutrophils in part through interaction with members of the carcinoembryonic antigen (CEA) family, which includes CEACAM3 (CD66d), a human neutrophil specific receptor for phagocytosis of bacteria. In the present work, we examined the effects of OpaI-expressing lgtF mutant on phagocytosis by HeLa-CEACAM3 cells and chemiluminescence responses in neutrophils. The results showed that lgtF mutant even expressing OpaI completely lost the ability to promote either phagocytosis mediated by CEACAM3 interaction in HeLa cells or chemiluminescence responses in neutrophils. These data indicated that Opa proteins in the lgtF mutant, which might result from the conformational change, cannot be functional.
Antigens, Bacterial ; chemistry ; genetics ; immunology ; metabolism ; Carbohydrate Sequence ; Carcinoembryonic Antigen ; genetics ; immunology ; Gene Expression Regulation ; HeLa Cells ; Host-Pathogen Interactions ; Humans ; Lipopolysaccharides ; chemistry ; immunology ; Luminescent Measurements ; Mutation ; Neisseria gonorrhoeae ; genetics ; metabolism ; pathogenicity ; Neutrophils ; immunology ; microbiology ; Phagocytosis

Staphylococcus aureus is a major cause of hospital-acquired infection. Because the bacteria are very easy to become resistant to antibiotics, vaccination is a main method against S. aureus infection. Clumping factor B (ClfB) is an adhesion molecule essential for S. aureus to colonize in the host mucosa and is regarded as an important target antigen. In this study, we successfully used Escherichia coli to express a segment encoding the N1-N3 regions of ClfB protein (Truncated-ClfB) cloned from S. aureus. The protein was purified by affinity and ion exchange chromatographies and gel filtration. Rabbits were immunized three times with purified Truncated-ClfB. After that, blood was collected to prepare serum which were then used for measurement of antibody level. Phagocytosis of S. aureus opsonized by the serum was determined by a flow cytometry. Results show that the serum IgG titer reached 1:640 000. Phagocytosed S. aureus by polymorphonuclear leukocytes were significantly more when the bacteria were opsonized by the serum from Truncated-ClfB immunized rabbits than those from no immunized group (P < 0.01). Therefore, the results indicated that Truncated-ClfB could be a promising vaccine candidate against S. aureus infection.
Adhesins, Bacterial ; immunology ; Animals ; Antibodies, Bacterial ; blood ; Escherichia coli ; Flow Cytometry ; Immune Sera ; Immunoglobulin G ; blood ; Opsonin Proteins ; immunology ; Phagocytosis ; Rabbits ; Staphylococcal Infections ; immunology ; Staphylococcus aureus

Xiyanping is used to treat infectious diseases with antibiotics in clinic. The aim of this study is to investigate the mechanism of Xiyanping through studying the effect of the combination of Xiyanping with Cefazolin on the chemotaxis and phagocytic function of peripheral blood neutrophils in mice. Ten healthy mice were in control group. Forty healthy mice in experimental group were infected with staphylococcus aureus, and were randomly divided further into four groups, i. e. model group, Xiyanping group, Cefazolin group and combination group (Xiyanping with Cefazolin). Mice in the control group and model group were given normal saline (NS) through abdomen while those in other groups were given Xiyanping, Cefazolin, and Xiyanping with Cefazolin, respectively. The chemotaxis of peripheral blood neutrophils was detected with the transwell method, and the phagocytic function of peripheral blood neutrophils was analyzed with flow cytometry (FCM). In the present study, there was no significance on the chemotactic index of peripheral blood neutrophils in all the groups (P > 0.05). The actual phagocytotic rate and index of peripheral blood neutrophils in the blank group, Xiyanping group, and the combination group were significantly higher than those of the model group and Cefazolin group (P < 0.05). However, those were not significant in the blank group, Xiyanping group, and the combination group (P > 0.05) or between the model group and Cefazolin group (P> 0.05). Our results suggested the combination of Xiyanping and Cefazolin could enhance the therapeutic effect by improving the phagocytic function of peripheral blood neutrophils.
Animals ; Anti-Bacterial Agents ; pharmacology ; Cefazolin ; pharmacology ; Chemotaxis ; Disease Models, Animal ; Drugs, Chinese Herbal ; pharmacology ; Mice ; Neutrophils ; cytology ; drug effects ; Phagocytosis ; Staphylococcal Infections ; immunology ; Staphylococcus aureus

Differentiated HL-60 is an effector cell widely used for the opsonophagocytic-killing assay (OPKA) to measure efficacy of pneumococcal vaccines. We investigated the correlation between phenotypic expression of immunoreceptors and phagocytic ability of HL-60 cells differentiated with N,N-dimethylformamide (DMF), all-trans retinoic acid (ATRA), or 1alpha, 25-dihydroxyvitamin D3 (VitD3) for 5 days. Phenotypic change was examined by flow cytometry with specific antibodies to CD11c, CD14, CD18, CD32, and CD64. Apoptosis was determined by flow cytometry using 7-aminoactinomycin D. Function was evaluated by a standard OPKA against serotype 19F and chemiluminescence-based respiratory burst assay. The expression of CD11c and CD14 gradually increased upon exposure to all three agents, while CD14 expression increased abruptly after VitD3. The expression of CD18, CD32, and CD64 increased during differentiation with all three agents. Apoptosis remained less than 10% until day 3 but increased after differentiation by DMF or ATRA. Differentiation with ATRA or VitD3 increased the respiratory burst after day 4. DMF differentiation showed a high OPKA titer at day 1 which sustained thereafter while ATRA or VitD3-differentiated cells gradually increased. Pearson analysis between the phenotypic changes and OPKA titers suggests that CD11c might be a useful differentiation marker for HL-60 cells for use in pneumococcal OPKA.
Antibodies, Bacterial/immunology ; Antigens, CD11c/metabolism ; Antigens, CD14/metabolism ; Antigens, CD18/metabolism ; Apoptosis/*immunology ; Biological Assay ; Cell Differentiation ; Cell Line, Tumor ; Cholecalciferol/pharmacology ; Dimethylformamide/pharmacology ; Flow Cytometry ; HL-60 Cells ; Humans ; Phagocytosis/*immunology ; Pneumococcal Vaccines/*immunology ; Receptors, IgG/metabolism ; Receptors, Immunologic/*biosynthesis ; Respiratory Burst/immunology ; Streptococcus pneumoniae/*immunology ; Tretinoin/pharmacology

Differentiated HL-60 is an effector cell widely used for the opsonophagocytic-killing assay (OPKA) to measure efficacy of pneumococcal vaccines. We investigated the correlation between phenotypic expression of immunoreceptors and phagocytic ability of HL-60 cells differentiated with N,N-dimethylformamide (DMF), all-trans retinoic acid (ATRA), or 1alpha, 25-dihydroxyvitamin D3 (VitD3) for 5 days. Phenotypic change was examined by flow cytometry with specific antibodies to CD11c, CD14, CD18, CD32, and CD64. Apoptosis was determined by flow cytometry using 7-aminoactinomycin D. Function was evaluated by a standard OPKA against serotype 19F and chemiluminescence-based respiratory burst assay. The expression of CD11c and CD14 gradually increased upon exposure to all three agents, while CD14 expression increased abruptly after VitD3. The expression of CD18, CD32, and CD64 increased during differentiation with all three agents. Apoptosis remained less than 10% until day 3 but increased after differentiation by DMF or ATRA. Differentiation with ATRA or VitD3 increased the respiratory burst after day 4. DMF differentiation showed a high OPKA titer at day 1 which sustained thereafter while ATRA or VitD3-differentiated cells gradually increased. Pearson analysis between the phenotypic changes and OPKA titers suggests that CD11c might be a useful differentiation marker for HL-60 cells for use in pneumococcal OPKA.
Antibodies, Bacterial/immunology ; Antigens, CD11c/metabolism ; Antigens, CD14/metabolism ; Antigens, CD18/metabolism ; Apoptosis/*immunology ; Biological Assay ; Cell Differentiation ; Cell Line, Tumor ; Cholecalciferol/pharmacology ; Dimethylformamide/pharmacology ; Flow Cytometry ; HL-60 Cells ; Humans ; Phagocytosis/*immunology ; Pneumococcal Vaccines/*immunology ; Receptors, IgG/metabolism ; Receptors, Immunologic/*biosynthesis ; Respiratory Burst/immunology ; Streptococcus pneumoniae/*immunology ; Tretinoin/pharmacology

In the present study, the effects of Pleurotus nebrodensis polysaccharide (PN-S) on the immune functions of immunosuppressed mice were determined. The immunosuppressed mouse model was established by treating the mice with cyclophosphamide (40 mg/kg/2d, CY) through intraperitoneal injection. The results showed that PN-S administration significantly reversed the CY-induced weight loss, increased the thymic and splenic indices, and promoted proliferation of T lymphocyte, B lymphocyte, and macrophages. PN-S also enhanced the activity of natural killer cells and increased the immunoglobulin M (IgM) and immunoglobulin G (IgG) levels in the serum. In addition, PN-S treatment significantly increased the phagocytic activity of mouse peritoneal macrophages. PN-S also increased the levels of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), interferon-γ (INF-γ), and nitric oxide (NOS) in splenocytes. qRT-PCR results also indicated that PN-S increased the mRNA expression of IL-6, TNF-α, INF-γ, and nitric oxide synthase (iNOS) in the splenocytes. These results suggest that PN-S treatment enhances the immune function of immunosuppressed mice. This study may provide a basis for the application of this fungus in adjacent immunopotentiating therapy against cancer and in the treatment of chemotherapy-induced immunosuppression.
Animals ; Antineoplastic Agents, Alkylating ; Biological Products ; pharmacology ; therapeutic use ; Cell Line ; Cyclophosphamide ; Immunity ; drug effects ; Immunologic Factors ; pharmacology ; therapeutic use ; Immunosuppression ; Interferon-gamma ; metabolism ; Interleukin-6 ; metabolism ; Macrophages ; drug effects ; metabolism ; Male ; Mice, Inbred BALB C ; Neoplasms ; drug therapy ; immunology ; Nitric Oxide ; metabolism ; Nitric Oxide Synthase Type II ; metabolism ; Phagocytosis ; drug effects ; Pleurotus ; chemistry ; Polysaccharides ; pharmacology ; therapeutic use ; Tumor Necrosis Factor-alpha ; metabolism

OBJECTIVETo investigate the effects of mannan-binding lectin (MBL) on the functions of human polymorphonuclear cells (PMNs).

METHODSELISA and Dot blot were performed to examine the binding between MBL and the microorganisms. Flow cytometry and fluorescence microscopy were employed to analyze the phagocytosis of FITC-labeled microorganisms by the PMNs. Real-time quantitative PCR was used to detect the expression levels of IL-1β, TNF-α and CD11b mRNA in the PMNs, and ELISA used to detect the levels of TNF-α and IL-6 in the supernatants of PMN culture. Nitro-blue tetrazolium reduction assay was used to estimate the levels of superoxide production.

RESULTSMBL bound to the microorganisms in a dose-dependent manner. MBL had no significant effect on phagocytosis of C. albicans and E.coli by the PMNs in the absence of human serum, but in presence of mixed MBL-deficient human sera, MBL promoted the phagocytosis of C. albicans, which could be blocked by mannan. Mannan treatment increased the expressions of IL-1β, TNF-α, IL-6 and CD11b and enhanced superoxide production in the PMNs.

CONCLUSIONMBL can promote phagocytosis of microorganisms by PMNs and increase the expressions of proinflammatory cytokines from PMNs in a complement lectin pathway-dependent manner.

Candida albicans ; immunology ; Cells, Cultured ; Cytokines ; immunology ; Escherichia coli ; immunology ; Humans ; Mannose-Binding Lectin ; blood ; Neutrophils ; immunology ; Phagocytosis ; Superoxides ; immunology

OBJECTIVETo investigate the effects and mechanisms of Gong-tone music on the immunological function in rats with the Chinese medicine syndrome of Liver (Gan)-qi stagnation and Spleen (Pi)-qi deficiency (LSSD).

METHODSTwenty five male Wistar rats of SPF grade were randomly divided into 5 groups: normal group, model group, Xiaoyao Powder () group, Gong-tone group and combined group (the combination of Gong-tone and Xiaoyao Powder), with 5 rats in each group. The rat model for the Chinese medicine syndrome of LSSD was induced by chronic bandage and irregular diet. The course of treatment was 21 days. After the treatment, the levels of serum gastrin and IgG were detected by enzyme-linked immunoabsorbent assay (ELISA). Phagocytosis of macrophages was detected by the neutral red uptake assay and T cell proliferation was investigated by 3-(4,5-dimethylthiazolyl)-2,5-diphenyltetrazolium bromide (MTT) assay.

RESULTSThe serum gastrin, macrophage phagocytosis, IgG level and proliferation ability of T cells in the model group were significantly decreased compared with those in the normal group (P <0.05). Compared with those in the model group, the serum levels of gastrin, macrophage phagocytosis, IgG level and proliferation ability of T cells in Gong-tone, Xiaoyao Powder, and combined groups were significantly increased (P <0.05). The combined group was superior to either Gong-tone group or Xiaoyao Powder group.

CONCLUSIONGong-tone music may upregulate the immunological function and play a role in adjuvant therapy in the Chinese syndrome of LSSD.

Animals ; Auditory Perception ; Behavior, Animal ; Body Weight ; Cell Proliferation ; Depression ; blood ; immunology ; Gastrins ; blood ; Immunoglobulin G ; blood ; Liver ; immunology ; Macrophages ; cytology ; Male ; Music ; Phagocytosis ; Qi ; Rats ; Rats, Wistar ; Spleen ; immunology ; Syndrome ; T-Lymphocytes ; cytology ; drug effects ; metabolism