Role of Macrophage Colony-Stimulating Factor for Staphylococcal Infection in the Oral Cavity.

OBJECTIVE: There are few valid indicators of oral infection owing to the complexity of pathogenic factors in oral diseases. Salivary markers are very useful for scrutinizing the symptoms of disease. To provide a reliable and useful predictive indicator of infection for opportunistic pathogens in individuals with compromised immune systems, such as those with periodontal diseases and Human Immunodeficiency Virus (HIV), this study examines opportunistic pathogens such as C. albicans and staphylococci and macrophage colony-stimulating factor (M-CSF) and CA125/MUC16 in saliva. The aim was to explore the correlations investigated among these factors. METHODS: Samples were divided into two groups (based on patient sex, the absence and presence of dentures in elderly, or HIV-positive patients and healthy subjects), and the correlation was analyzed in two groups of elderly patients with periodontal disease (64.5 ± 11.2 years old) and HIV-infected patients (41.9 ± 8.4 years old). Healthy subjects (33.8 ± 9.1 years old) were also analyzed as a control. Levels of C. albicans, staphylococci, and M-CSF, which is an immunological factor for the differentiation of macrophage, and CA125/MUC16, which provides a protective lubricating barrier against infection, were investigated. RESULTS: A significant and positive correlation between the levels of M-CSF and staphylococci was found in elderly individuals and HIV-positive patients treated with antiretroviral therapy. A significant and positive correlation between the levels of M-CSF and CD125/MUC16 was also found in both patients. These correlations were enhanced in both patients as compared with healthy subjects. CONCLUSION: Salivary M-CSF might be useful as a new indicator of opportunistic infection caused by staphylococci and a defense against infection in immunocompromised hosts.

Karyotypic analysis and isolation of four DNA markers of the scleractinian coral Favitespentagona (Esper, 1795) (Scleractinia, Anthozoa, Cnidaria).

We performed conventional and molecular cytogenetic studies on the Favitespentagona Esper, 1795, a scleractinian coral mostly found along the west coast of Japan. Karyotype analysis of F.pentagona by G-banding revealed a karyogram containing a homogenously staining region (HSR) on chromosome 10 in more than 50% of the examined metaphase spreads. This HSR consisted of sequences from 18S ribosomal RNA (rRNA) genes, as demonstrated by fluorescence in situ hybridization (FISH) and DNA sequencing. We highlighted the development of four chromosomal FISH markers from repetitive genes such as U2 small nuclear RNA linked to 5S rRNA sequence (U2 snRNA-5S), 18S rRNA, histone H3, and uncharacterized gene FP-9X. The chromosomal locations of the U2 snRNA-5S and 18S RNA were on the terminal end of long arm of chromosomes 2 and 10, respectively, while the histone H3 and the uncharacterized gene were located near the centromeres of chromosomes 1 and 9, respectively. These FISH markers will improve the karyotyping of F.pentagona from mitotic preparations which helps in widening our understanding of coral genetic structure and chromosome organization. In addition, these improvements in karyotyping will provide the basis in constructing of chromosome-level genome assembly for F.pentagona.

Structure and Stereochemistry of Amphidinolide N Congeners from Marine Dinoflagellate Amphidinium Species.

Two highly potent cytotoxic 26-membered macrolides, isocaribenolide-I (1) and a chlorohydrin 2, together with known amphidinolide N (3), have been isolated from a free-swimming dinoflagellate Amphidinium species (KCA09053 and KCA09056 strains) collected off Iriomote Island, Japan. The structures of 1 and 2 were determined to be a congener of 3 with an isobutyl terminus and the chlorohydrin form of 3, respectively, by detailed analyses of spectroscopic data. The relative stereochemistries of 1 and 2 were elucidated by the conformational analyses based on NMR data.

Reduction of Spermidine Content Resulting from Inactivation of Two Arginine Decarboxylases Increases Biofilm Formation in Synechocystis sp. Strain PCC 6803.

The phototropic bacterium Synechocystis sp. strain PCC 6803 is able to adapt its morphology in order to survive in a wide range of harsh environments. Under conditions of high salinity, planktonic cells formed cell aggregates in culture. Further observations using crystal violet staining, confocal laser scanning microscopy, and field emission-scanning electron microscopy confirmed that these aggregates were Synechocystis biofilms. Polyamines have been implicated in playing a role in biofilm formation, and during salt stress the content of spermidine, the major polyamine in Synechocystis, was reduced. Two putative arginine decarboxylases, Adc1 and Adc2, in Synechocystis were heterologously expressed in Escherichia coli and purified. Adc2 had high arginine decarboxylase activity, whereas Adc1 was much less active. Disruption of the adc genes in Synechocystis resulted in decreased spermidine content and formation of biofilms even under nonstress conditions. Based on the characterization of the adc mutants, Adc2 was the major arginine decarboxylase whose activity led to inhibition of biofilm formation, and Adc1 contributed only minimally to the process of polyamine synthesis. Taken together, in Synechocystis the shift from planktonic lifestyle to biofilm formation was correlated with a decrease in intracellular polyamine content, which is the inverse relationship of what was previously reported in heterotroph bacteria.IMPORTANCE There are many reports concerning biofilm formation in heterotrophic bacteria. In contrast, studies on biofilm formation in cyanobacteria are scarce. Here, we report on the induction of biofilm formation by salt stress in the model phototrophic bacterium Synechocystis sp. strain PCC 6803. Two arginine decarboxylases (Adc1 and Adc2) possess function in the polyamine synthesis pathway. Inactivation of the adc1 and adc2 genes leads to biofilm formation even in the absence of salt. The shift from planktonic culture to biofilm formation is regulated by a decrease in spermidine content in Synechocystis This negative correlation between biofilm formation and polyamine content, which is the opposite of the relationship reported in other bacteria, is important not only in autotrophic but also in heterotrophic bacteria.

Spirulina lipopolysaccharides inhibit tumor growth in a Toll-like receptor 4-dependent manner by altering the cytokine milieu from interleukin-17/interleukin-23 to interferon-γ.

Th17 cells and the cytokine they produce, interleukin (IL)-17, play an important role in tumor progression in humans and in mice. IL-6 and IL-23 are critical cytokines for the differentiation and propagation of Th17 cells, respectively. Bacterial lipopolysaccharides (LPS) are known to stimulate immune cells to produce such inflammatory cytokines. Contrary to Escherichia coli (E. coli) LPS, LPS from Spirulina has low toxicity and barely induces in vivo production of IL-6 and IL-23 in mice. We examined the antitumor effects of Spirulina LPS compared to E. coli LPS in an MH134 hepatoma model. Administration of Spirulina LPS suppressed tumor growth in C3H/HeN mice, but not in Toll-like receptor 4 (TLR4)-mutant C3H/HeJ mice, by reducing serum levels of IL-17 and IL-23, while increasing interferon (IFN)-γ levels. The antitumor activity and IFN-γ production were mediated by T cells. Moreover, in vitro experiments showed that Spirulina LPS impaired the antigen-presenting function that supports the generation of IL-17-producing cells in a toll-like receptor (TLR)4-dependent manner. Of note, injection of anti-IL-17 antibody in tumor-bearing C3H/HeN mice in the absence of Spirulina LPS markedly suppressed tumor growth and augmented IFN-γ responses. Thus, our results support the notion that IFN-γ and IL-17/IL-23 mutually regulate Th17 and Th1 responses in tumor-bearing hosts, and Spirulina LPS modulates the balance of the IFN-γ-IL-17/IL-23 axis towards IFN-γ production, which leads to tumor inhibition. Furthermore, Spirulina LPS effectively inhibited the spontaneous development of mammary tumors. This study has important implications for the exploitation of TLR-based immunomodulators for cancer immunotherapy.

Iriomoteolides-10a and 12a, Cytotoxic Macrolides from Marine Dinoflagellate Amphidinium Species.

Two new macrolides, iriomoteolides-10a (1) and -12a (2), have been isolated from a marine dinoflagellate Amphidinium sp. (KCA09053 strain), and their structures were elucidated on the basis of a detailed two dimensional (2D)-NMR analysis. Compound 1 is a novel 21-membered Amphidinium macrolide, which contains one tetrahydrofuran ring, two ketone carbonyls, two hydroxyl groups, and six one-carbon branches. Compound 2 is a new 12-membered macrolide related to amphidinolide Q. Compound 1 exhibited cytotoxic activity against human cervix adenocarcinoma HeLa and murine hepatocellular carcinoma MH134 cells.

Identification of homogeneously staining regions by G-banding and chromosome microdissection, and FISH marker selection using human Alu sequence primers in a scleractinian coral Coelastrea aspera Verrill, 1866 (Cnidaria).

Karyotype analysis was performed on the scleractinian coral Coelastrea aspera Verrill, 1866, commonly found along temperate coasts in Japan (30-35°N) and in coastal waters in the Indian and Pacific oceans. G-banding of Coelastrea aspera was successfully performed, although the banding pattern was not as clear as that in mammals. The karyogram clearly revealed that this coral had a homogeneously staining region (hsr) in chromosome 11. This hsr consisted of ribosomal RNA (rRNA) related genes, which was demonstrated by fluorescence in situ hybridization (FISH) with probes generated using 28S ribosomal DNA (rDNA) primers and those generated through chromosome microdissection. In addition, we conducted silver-stained nucleolus organizer region (Ag-NOR) analysis and found Ag depositions in the interphase nuclei but not on rRNA gene loci and hsr(s) in the mitotic stage. The hsr of this coral was observed in approximately 50% of the metaphase spreads analyzed. This may explain the diversity of coral rDNA based on the molecular study of sequence analysis. Furthermore, it was discovered that human telomere and Alu repeated sequences were present in this Coelastrea aspera. Probes derived from human Alu sequences are expected to play an important role in the classification of corals. Overall, our data can be of great value in discriminating among scleractinian coral species and understanding their genetics, including chromosomal evolution.

Comparative analysis of kdp and ktr mutants reveals distinct roles of the potassium transporters in the model cyanobacterium Synechocystis sp. strain PCC 6803.

Photoautotrophic bacteria have developed mechanisms to maintain K(+) homeostasis under conditions of changing ionic concentrations in the environment. Synechocystis sp. strain PCC 6803 contains genes encoding a well-characterized Ktr-type K(+) uptake transporter (Ktr) and a putative ATP-dependent transporter specific for K(+) (Kdp). The contributions of each of these K(+) transport systems to cellular K(+) homeostasis have not yet been defined conclusively. To verify the functionality of Kdp, kdp genes were expressed in Escherichia coli, where Kdp conferred K(+) uptake, albeit with lower rates than were conferred by Ktr. An on-chip microfluidic device enabled monitoring of the biphasic initial volume recovery of single Synechocystis cells after hyperosmotic shock. Here, Ktr functioned as the primary K(+) uptake system during the first recovery phase, whereas Kdp did not contribute significantly. The expression of the kdp operon in Synechocystis was induced by extracellular K(+) depletion. Correspondingly, Kdp-mediated K(+) uptake supported Synechocystis cell growth with trace amounts of external potassium. This induction of kdp expression depended on two adjacent genes, hik20 and rre19, encoding a putative two-component system. The circadian expression of kdp and ktr peaked at subjective dawn, which may support the acquisition of K(+) required for the regular diurnal photosynthetic metabolism. These results indicate that Kdp contributes to the maintenance of a basal intracellular K(+) concentration under conditions of limited K(+) in natural environments, whereas Ktr mediates fast potassium movements in the presence of greater K(+) availability. Through their distinct activities, both Ktr and Kdp coordinate the responses of Synechocystis to changes in K(+) levels under fluctuating environmental conditions.

Amphirionin-2, a novel linear polyketide with potent cytotoxic activity from a marine dinoflagellate Amphidinium species.

A novel linear polyketide, amphirionin-2 (1), with two unique hexahydrofuro[3,2-b]furan moieties has been isolated from the cultivated algal cells of a benthic dinoflagellate Amphidinium sp. (strain KCA09051). The structure was elucidated on the basis of detailed analyses of 2D NMR data, and the absolute configuration of C-5 was determined by using modified Mosher's method. Amphirionin-2 (1) exhibited potent cytotoxic activity against human colon carcinoma Caco-2 cells and human lung adenocarcinoma A549 cells.

Amphirionin-4 with potent proliferation-promoting activity on bone marrow stromal cells from a marine dinoflagellate amphidinium species.

A linear polyketide, amphirionin-4 (1), has been isolated from cultivated algal cells of the marine dinoflagellate Amphidinium species. The structure was elucidated on the basis of detailed analyses of 1D and 2D NMR data, and the absolute configurations of C-4 and C-8 were determined using the modified Mosher's method. Amphirionin-4 (1) exhibited extremely potent proliferation-promoting activity on murine bone marrow stromal ST-2 cells (950% promotion) at a concentration of 0.1 ng/mL.

Peridinin from the marine symbiotic dinoflagellate, Symbiodinium sp., regulates eosinophilia in mice.

Peridinin and fucoxanthin, which are natural carotenoids isolated from a symbiotic dinoflagellate, Symbiodinium sp., and a brown alga, Petalonia fascia, respectively, were compared for inhibitory effects on delayed-type hypersensitivity in mice. The number of eosinophils at the site of inflammation and in peripheral blood was compared for the administration of peridinin and fucoxanthin applied by painting and intraperitoneally. Peridinin, but not the structurally-related fucoxanthin, significantly suppressed the number of eosinophils in both the ear lobe and peripheral blood. Furthermore, peridinin applied topically, but not administered intraperitoneally, suppressed the level of eotaxin in the ears of sensitized mice. Fucoxanthin weakly suppressed the concentration of eotaxin in ears only by intraperitoneal administration. Although both carotenoids inhibited the migration of eosinophils toward eotaxin, the inhibitory effect of peridinin was higher than that of fucoxanthin. Peridinin may be a potential agent for suppressing allergic inflammatory responses, such as atopic dermatitis, in which eosinophils play a major role in the increase of inflammation.

Molecular cytogenetic analysis of the scleractinian coral Acropora solitaryensis Veron & Wallace 1984.

We performed a molecular cytogenetic investigation of the scleractinian coral Acropora solitaryensis, which is dominant in the temperate region of Japan (30-35°N). Molecular cytogenetic analysis, using fluorescence in situ hybridization (FISH), was carried out for karyotyping and gene mapping. We propose the karyotype of this coral (2n = 30) based on C-banding and FISH analyses. FISH mapping of the rRNA gene was carried out with a probe generated by PCR amplification using rRNA gene primers. Furthermore, the telomeres and centromeres of all chromosomes were visualized using FISH. By comparative genomic hybridization using DNA from sperm and unfertilized eggs of this coral, we offer evidence suggesting the existence of sex chromosomes in this species. Collectively, these data advance our understanding of coral genetics.

Autonomous cure of damaged human intestinal epithelial cells by TLR2 and TLR4-dependent production of IL-22 in response to Spirulina polysaccharides.

In order to analyze the damage of human epithelial cells, we used human quasi-normal FPCK-1-1 cells derived from a colonic polyp in a patient with familial adenomatous polyposis as a monolayer, which is co-cultured with peptidoglycan (PGN)-stimulated THP-1 cells. Co-cultured FPCK-1-1 cells showed a decreased transepithelial electrical resistance (TER) and the lower level of claudin-2. When Spirulina complex polysaccharides were added one day before the start of the co-culture, there was no decrease of TER and claudin-2 (early phase damage). In contrast, when Spirulina complex polysaccharides were added to FPCK-1-1 cells after the level of TER had decreased, there was no recovery at the level of claudin-2, though the TER level recovered (late phase damage). The mucosa reconstitution is suggested to be involved in the recovery from the damaged status. Interestingly, autonomous recovery of FPCK-1-1 cells from both the early and late phase damage requires the production of IL-22, because anti-IL-22 antibodies inhibited recovery in these cases. Antibodies against either TLR2 or TLR4 inhibited the production of IL-22 from FPCK-1-1 colon epithelial cells, suggesting that signals through TLR2 and TLR4 are necessary for autonomous recovery of FPCK-1-1 colon epithelial cells by producing IL-22. In conclusion, we have established a useful model for the study of intestinal damage and recovery using human colon epithelial cells and our data suggest that damage to human colon epithelial cells can, at least in part, be recovered by the autonomous production of IL-22 in response to Spirulina complex polysaccharides.

Regulatory effects of Spirulina complex polysaccharides on growth of murine RSV-M glioma cells through Toll-like receptor 4.

This study is the first to report that Spirulina complex polysaccharides (CPS) suppress glioma growth by down-regulating angiogenesis via a Toll-like receptor 4 signal. Murine RSV-M glioma cells were implanted s.c. into C3H/HeN mice and TLR4 mutant C3H/HeJ mice. Treatment with either Spirulina CPS or Escherichia coli (E. coli) lipopolysaccharides (LPS) strongly suppressed RSV-M glioma cell growth in C3H/HeN, but not C3H/HeJ, mice. Glioma cells stimulated production of interleukin (IL)-17 in both C3H/HeN and C3H/HeJ tumor-bearing mice. Treatment with E. coli LPS induced much greater IL-17 production in tumor-bearing C3H/HeN mice than in tumor-bearing C3H/HeJ mice. In C3H/HeN mice, treatment with Spirulina CPS suppressed growth of re-transplanted glioma; however, treatment with E. coli LPS did not, suggesting that Spirulina CPS enhance the immune response. Administration of anti-cluster of differentiation (CD)8, anti-CD4, anti-CD8 antibodies, and anti-asialo GM1 antibodies enhanced tumor growth, suggesting that T cells and natural killer cells or macrophages are involved in suppression of tumor growth by Spirulina CPS. Although anti-interferon-γ antibodies had no effect on glioma cell growth, anti-IL-17 antibodies administered four days after tumor transplantation suppressed growth similarly to treatment with Spirulina CPS. Less angiogenesis was observed in gliomas from Spirulina CPS-treated mice than in those from saline- or E. coli LPS-treated mice. These findings suggest that, in C3H/HeN mice, Spirulina CPS antagonize glioma cell growth by down-regulating angiogenesis, and that this down-regulation is mediated in part by regulating IL-17 production.

Multiple sites of highly amplified DNA sequences detected by molecular cytogenetic analysis in HS-RMS-2, a new pleomorphic rhabdomyosarcoma cell line.

A molecular cytogenetic analysis was performed on HS-RMS-2, a cell line established in this laboratory from a rare pleomorphic type of rhabdomyosarcoma. G-banding and multicolor-FISH analyses revealed that the cells have a complex chromosomal composition. Comparative genomic in situ hybridization (CGH) detected eight highly amplified regions at 1p36.1-p36.2, 1p31-p32, 1q21-q31, 8q12-q21, 8q24-qter, 11q12-q13, 12q13-q14 and 18q12-q22, suggesting the co-existence of multiple amplified oncogenes in these tumor cells. Reverse chromosome painting, using a probe regenerated by microdissection of a long marker chromosome, revealed the native location of three of eight possible genes to be on chromosomes 1p31-32, 12q14 and 18q21. FISH using BAC and cosmid probes revealed amplification of JUN (1p31), MYC (8q24), CCND1 (11q13), INT2 (11q13.3), MDM2 (12q14.3-q15) and MALT (18q21). These findings indicate that at least eight amplified oncogenes may contribute to the pathogenesis of a rare pleomorphic type of rhabdomyosarcoma. This new cell line should prove useful for in vitro preclinical studies of molecularly targeted therapies.

Effects of Gametophytes of Ecklonia Kurome on the Levels of Glucose and Triacylglycerol in db/db, Prediabetic C57BL/6J and IFN-γ KO Mice.

We have studied edible algae that have the potential to down-regulate blood glucose. In Japan, Ecklonia species have been believed to improve the circulation of blood. In this study, we used leptin receptor deficient type 2 diabetes model mice (db/db) and prediabetic C57BL/6J mice. We also focused on the role of IFN-γ in the control of blood levels of triacylglycerol and glucose, because it is reportedly engaged in the regulation of energy consumption together with leptin. We report that gametophytes of Ecklonia kurome down-regulate the blood level of glucose and serum level of triacylglycerol in db/db. We also report that gametophytes of Ecklonia kurome down-regulate the level of glucose but not the level of triacylglycerol in prediabetic C57BL/6J mice induced by a high fat diet. They increased the level of triacylglycerol compared to that of control group in C57BL/6J, but not in IFN-γ KO mice. Gametophytes of Ecklonia kurome were administered orally to prediabetic C57BL/6J and IFN-γ KO mice and oral glucose tolerance tests were performed to evaluate the effects of algae. During the administration of the normal diet, we found a higher level of blood glucose in a glucose tolerance test of IFN-γ KO mice compared with that of C57BL/6J. Although a high fat diet induced a higher level of blood glucose compared with a normal diet group in a glucose tolerance test of C57BL/6J mice, this effect of high fat diet was not observed clearly at first but appeared three hours after glucose administration in IFN-γ KO mice. Gametophytes of Ecklonia kurome down-regulated the level of blood glucose in both C57BL/6J and IFN-γ KO mice, when administered a normal diet after making them prediabetic. These results suggest that Ecklonia kurome are effective to down-regulate the blood glucose and IFN-γ is involved in the regulation of blood glucose and triacylglycerol.

EAL domain protein YdiV acts as an anti-FlhD4C2 factor responsible for nutritional control of the flagellar regulon in Salmonella enterica Serovar Typhimurium.

Flagellar operons are divided into three classes with respect to their transcriptional hierarchy in Salmonella enterica serovar Typhimurium. The class 1 gene products FlhD and FlhC act together in an FlhD(4)C(2) heterohexamer, which binds upstream of the class 2 promoters to facilitate binding of RNA polymerase. In this study, we showed that flagellar expression was much reduced in the cells grown in poor medium compared to those grown in rich medium. This nutritional control was shown to be executed at a step after class 1 transcription. We isolated five Tn5 insertion mutants in which the class 2 expression was derepressed in poor medium. These insertions were located in the ydiV (cdgR) gene or a gene just upstream of ydiV. The ydiV gene is known to encode an EAL domain protein and to act as a negative regulator of flagellar expression. Gene disruption and complementation analyses revealed that the ydiV gene is responsible for nutritional control. Expression analysis of the ydiV gene showed that its translation, but not transcription, was enhanced by growth in poor medium. The ydiV mutation did not have a significant effect on either the steady-state level of flhDC mRNA or that of FlhC protein. Purified YdiV protein was shown in vitro to bind to FlhD(4)C(2) through interaction with FlhD subunit and to inhibit its binding to the class 2 promoter, resulting in inhibition of FlhD(4)C(2)-dependent transcription. Taking these data together, we conclude that YdiV is a novel anti-FlhD(4)C(2) factor responsible for nutritional control of the flagellar regulon.

High-grade mucinous tubular and spindle cell carcinoma: comparative genomic hybridization study.

Mucinous tubular and spindle cell carcinoma (MTSCC) has recently been integrated into the World Health Organization classification. Although MTSCC is generally a low-grade carcinoma, MTSCC with high-grade morphology has been recently reported. We present the first case of high-grade MTSCC with comparative genomic hybridization findings. A 60-year-old Japanese man presented with weight loss and general fatigue. He underwent radical nephrectomy because of the clinical diagnosis of renal cancer. Histologic examination of renal tumor showed findings of high-grade MTSCC. Comparative genomic hybridization analysis showed gain of chromosomes 1q, 7, 16, 19q, and Y and loss of chromosomes 1p, 6p, 8p, 11q (del(11)(q23)), and 13. G-band karyotype showed gain of chromosomes 2, 3, 5, 7, 12, 16, and 20 and loss of chromosome 15. Results of our molecular genetic analysis support the idea that high-grade MTSCC is a real counterpart of low-grade MTSCC. There is no evidence to designate such tumors as unclassified renal cell carcinoma.

Chromosomal abnormalities of clear cell renal cell carcinoma: frequent gain of chromosome 7.

Gain of chromosome 7 is well known to be a characteristic abnormality of papillary renal cell carcinoma (RCC). The purpose of the present study was to perform cytogenetic analysis of G-band karyotype in 16 clear cell RCC obtained from nephrectomy. The age of patients ranged from 50 to 79 years and the tumor size in largest dimension ranged from 1.8 to 6.2 cm. As a result, the structural abnormality of chromosome 3 was most frequently observed (eight clones). Loss of chromosome 3 and gain of chromosome 7 followed (four clones). Among four clones showing gain of chromosome 7, two were associated with the abnormality of chromosome 3 and the remaining two were devoid of the abnormalities of chromosome 3. In addition, none of all four tumors showing gain of chromosome 7 demonstrated any foci of papillary growth pattern. The present study shows that gain of chromosome 7 is not exclusive to papillary RCC, but it can be found in clear cell RCC as well, and this finding may represent a diagnostic pitfall in distinguishing clear cell RCC from papillary RCC.

Participation of CD11b and F4/80 molecules in the conjunctival eosinophilia of experimental allergic conjunctivitis.

BACKGROUND: CD11b and F4/80 are macrophage surface markers. How these molecules participate in allergic eosinophil infiltration remains unclear. We examined the roles CD11b and F4/80 play in the conjunctival eosinophil infiltration associated with experimental allergic conjunctivitis. METHODS: Ragweed-immunized BALB/c mice were challenged with ragweed in eye drops to induce conjunctival eosinophil infiltration. The effect of challenge on conjunctival CD11b+ and F4/80+ cell numbers was determined by immunohistochemistry. In the same model, blocking anti-CD11b and anti-F4/80 Abs were injected intraperitoneally during the induction or the effector phase, or subconjunctivally 2 h before challenge, to determine their effect on challenge-induced conjunctival eosinophilia. To examine whether eosinophils express CD11b and F4/80 molecules, splenocytes from IL-5 gene-electroporated mice were subjected to flow cytometric analysis. To clarify the involvement of CD11b and F4/80 in conjunctival eosinophil infiltration, mice were intraperitoneally injected with anti-CD11b and anti-F4/80 Abs and then subconjunctivally injected with eotaxin to induce conjunctival eosinophilia. RESULTS: Ragweed challenge elevated conjunctival CD11b+ and F4/80+ cell numbers. Systemic anti-CD11b and anti-F4/80 Ab treatments during the effector phase, but not in either the induction phase or the local injection of Ab, suppressed conjunctival eosinophil infiltration in ragweed-induced conjunctivitis. Most splenic eosinophils from IL-5 gene-introduced mice expressed CD11b and F4/80. Systemic anti-CD11b and anti-F4/80 Ab treatment suppressed conjunctival eosinophilia induced by subconjunctival eotaxin injection. CONCLUSIONS: CD11b and F4/80 appear to participate in conjunctival eosinophil infiltration in allergic conjunctivitis. Their involvement in conjunctival eosinophilia appears to be due to their expression on eosinophils rather than on macrophages.