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Specialized pro-resolving mediators (SPMs) are multifunctional lipid mediators that participate in the resolution of inflammation. We have recently described that oral epithelial cells (OECs) express receptors of the SPM resolvin RvD1n-3 DPA and that cultured OECs respond to RvD1n-3 DPA addition by intracellular calcium release, nuclear receptor translocation and transcription of genes coding for antimicrobial peptides. The aim of the present study was to assess the functional outcome of RvD1n-3 DPA–signaling in OECs under inflammatory conditions. To this end, we performed transcriptomic analyses of TNF-α-stimulated cells that were subsequently treated with RvD1n-3 DPA and found significant downregulation of pro-inflammatory nuclear factor kappa B (NF-κB) target genes. Further bioinformatics analyses showed that RvD1n-3 DPA inhibited the expression of several genes involved in the NF-κB activation pathway. Confocal microscopy revealed that addition of RvD1n-3 DPA to OECs reversed TNF-α-induced nuclear translocation of NF-κB p65. Co-treatment of the cells with the exportin 1 inhibitor leptomycin B indicated that RvD1n-3 DPA increases nuclear export of p65. Taken together, our observations suggest that SPMs also have the potential to be used as a therapeutic aid when inflammation is established.

Specialized pro-resolving mediators (SPMs) are multifunctional lipid mediators that participate in the resolution of inflammation. We have recently described that oral epithelial cells (OECs) express receptors of the SPM resolvin RvD1

Oral lichen planus (OLP) is a chronic inflammatory disease displaying ultrastructural disturbances in epithelial hemidesmosomes. The expression of several key hemidesmosomal components in OLP as well as in normal buccal mucosa is, however, unknown. The aim of the study was therefore to examine intracellular and extracellular components involved in hemidesmosomal attachment, in OLP (n = 20) and in normal buccal mucosa (n = 10), by immunofluorescence. In normal buccal mucosa, laminin-α3γ2, integrin-α6β4, CD151, collagen α-1(XVII) chain, and dystonin showed linear expression along the basal membrane, indicating the presence of type I hemidesmosomes. Plectin stained most epithelial cell membranes and remained unphosphorylated at S4642. In OLP, most hemidesmosomal molecules examined showed disturbed expression consisting of discontinuous increases, apicolateral location, and/or intracellular accumulation. Plectin showed S4642-phosphorylation at the basement membrane, and deposits of laminin-α3 and laminin-γ2 were found within the connective tissue. The disturbed expression of hemidesmosomal proteins in OLP indicates deficient attachment of the basal cell layer, which can contribute to detachment and cell death of basal keratinocytes seen in the disease.

Chronic inflammatory responses can inflict permanent damage to host tissues. Specialized pro-resolving mediators downregulate inflammation but also can have other functions. The aim of this study was to examine whether oral epithelial cells express the receptors FPR2/ALX and DRV1/GPR32, which bind RvD1

Chronic inflammatory responses can inflict permanent damage to host tissues. Specialized pro-resolving mediators downregulate inflammation but also can have other functions. The aim of this study was to examine whether oral epithelial cells express the receptors FPR2/ALX and DRV1/GPR32, which bind RvD1n-3 DPA, a recently described pro-resolving mediator derived from omega-3 docosapentaenoic acid (DPA), and whether RvD1n-3 DPA exposure induced significant responses in these cells. Gingival biopsies were stained using antibodies to FPR2/ALX and DRV1/GPR32. Expression of FPR2/ALX and DRV1/GPR32 was examined in primary oral epithelial cells by qRT-PCR, flow cytometry, and immunofluorescence. The effect of RvD1n-3 DPA on intracellular calcium mobilization and transcription of beta-defensins 1 and 2, and cathelicidin was evaluated by qRT-PCR. FPR2/ALX and DRV1/GPR32 were expressed by gingival keratinocytes in situ. In cultured oral epithelial cells, FPR2/ALX was detected on the cell surface, whereas FPR2/ALX and DRV1/GPR32 were detected intracellularly. Exposure to RvD1n-3 DPA induced intracellular calcium mobilization, FPR2/ALX internalization, DRV1/GPR32 translocation to the nucleus, and significantly increased expression of genes coding for beta-defensin 1, beta-defensin 2, and cathelicidin. This shows that the signal constituted by RvD1n-3 DPA is recognized by oral keratinocytes and that this can strengthen the antimicrobial and regulatory potential of the oral epithelium.

The number of langerin-expressing antigen-presenting cells is higher in oral lichen planus than in normal oral mucosa. However, langerin may be expressed by several functionally different lineages of antigen presenting cells (APCs), and this has important implications for our understanding of the pathogenesis of oral lichen planus. The aim of this study was to determine the origin of the langerin-expressing APCs. To this end, we examined oral mucosal biopsies from healthy persons and patients with oral lichen planus using multicolor immunofluorescence. In normal oral mucosa, a substantial fraction of Langerhans cells expressed Ki-67, indicating that steady-state oral mucosal Langerhans cells are at least partially maintained by self-renewal. In oral lichen planus, the numbers of Langerhans cells were higher but proliferation was not altered, indicating that the higher cell numbers appeared to depend on recruited dendritic cell (DC)-precursors. Moreover, we found a markedly higher number of langerin+ APCs within the lamina propria of oral lichen planus lesions. Such cells did not display monocyte- or macrophage markers, but rather showed a phenotype compatible with tissue-elicited IRF4+ cDC2. Detailed understanding of how the oral mucosal APC network is regulated and the functional capacities of the different ontogenies may identify novel treatment targets for oral lichen planus.

Keratins form intermediate filaments of the cytoskeleton in keratinocytes and have roles in cell structure, signaling, intracellular transport, and cell death. Oral lichen planus (OLP) is an oral inflammatory disease with derangements in basal keratinocytes and disruption of the basal membrane. Here, we focused on epithelial expression of keratins 8, 18, and 19 because these proteins are known to modulate cell death. Biopsies were taken from buccal oral mucosa of persons with normal oral mucosa (n = 10) or atrophic OLP (n = 10). Cultured normal oral keratinocytes (n = 4) showed expression of mRNA and protein for keratins 8, 18, and 19. Immunohistochemistry showed consistent staining for keratins 8 and 18 in basal keratinocytes of normal oral mucosa. In OLP, staining for keratin (K)8 was mostly negative and staining for K18 was weak. Keratin 19 was expressed irregularly in most biopsies of normal oral mucosa and not at all in OLP. Several mononuclear leukocytes in the cellular infiltrate showed membrane staining for K8 and K18. Positive staining for K16 confirmed partial collapse of the basal cell layer in OLP. The basal cell niche in OLP therefore appeared to be partly populated with keratinocytes demonstrating a higher degree of differentiation (K8- K18- K19- K16+ ); consequently, such areas may be more susceptible to the action of cell death factors released from the cell infiltrate as a result of lacking the protective, normal keratin present in the basal epithelial cell layer of normal oral mucosa.

Streptococcus pneumoniae is a bacterial pathogen that causes various diseases of public health concern worldwide. Current pneumococcal vaccines target the capsular polysaccharide surrounding the cells. However, only up to 13 of more than 90 pneumococcal capsular serotypes are represented in the current conjugate vaccines. In this study, we used two experimental approaches to evaluate the potential of Streptococcus mitis, a commensal that exhibits immune cross-reactivity with S. pneumoniae, to confer protective immunity to S. pneumoniae lung infection in mice. First, we assessed the immune response and protective effect of wild-type S. mitis against lung infection by S. pneumoniae strains D39 (serotype 2) and TIGR4 (serotype 4). Second, we examined the ability of an S. mitis mutant expressing the S. pneumoniae type 4 capsule (S. mitis TIGR4cps) to elicit focused protection against S. pneumoniae TIGR4. Our results showed that intranasal immunization of mice with S. mitis produced significantly higher levels of serum IgG and IgA antibodies reactive to both S. mitis and S. pneumoniae, as well as enhanced production of interleukin 17A (IL-17A), but not gamma interferon (IFN-γ) and IL-4, compared with control mice. The immunization resulted in a reduced bacterial load in respiratory tissues following lung infection with S. pneumoniae TIGR4 or D39 compared with control mice. With S. mitis TIGR4cps, protection upon challenge with S. pneumoniae TIGR4 was superior. Thus, these findings show the potential of S. mitis to elicit natural serotype-independent protection against two pneumococcal serotypes and to provide the benefits of the well-recognized protective effect of capsule-targeting vaccines. IMPORTANCEStreptococcus pneumoniae causes various diseases worldwide. Current pneumococcal vaccines protect against a limited number of more than 90 pneumococcal serotypes, accentuating the urgent need to develop novel prophylactic strategies. S. pneumoniae and the commensal Streptococcus mitis share immunogenic characteristics that make S. mitis an attractive vaccine candidate against S. pneumoniae. In this study, we evaluated the potential of S. mitis and its mutant expressing pneumococcal capsule type 4 (S. mitis TIGR4cps) to induce protection against S. pneumoniae lung infection in mice. Our findings show that intranasal vaccination with S. mitis protects against S. pneumoniae strains D39 (serotype 2) and TIGR4 (serotype 4) in a serotype-independent fashion, which is associated with enhanced antibody and T cell responses. Furthermore, S. mitis TIGR4cps conferred additional protection against S. pneumoniae TIGR4, but not against D39. The findings highlight the potential of S. mitis to generate protection that combines both serotype-independent and serotype-specific responses.

Background Oral lichen planus (OLP) is a common T-cell-dominated oral chronic inflammatory disease occurring in periods of remission, quiescence, activity with pronounced inflammation, and acute ulceration. Cell infiltrates in OLP contain varying numbers of CD4+ T cells expressing the transcription factor FoxP3. FoxP3+CD4+ T cells are, however, a heterogeneous cell population containing suppressive and non-suppressive cells, and their distribution in infiltrates from OLP is unknown. Methods Biopsies were taken from normal oral mucosa (n = 8) and OLP lesions (n = 19), and a set of in situ methods for the determination of the functional phenotype of FoxP3+CD4+ T cells was applied. Results Numbers of FoxP3+CD4+ T cells were highest in the atrophic form of the disease, yet low in the ulcerative form. The main FoxP3+CD4+ T-cell population observed was FoxP3+CD45RA−CD25+CD45RO+ and CD15s−, a phenotype delineating a non-suppressive subset. Numbers of cells with an actively suppressing phenotype (FoxP3+CD45RA−CD25+CD45RO+ and CD15s+) were, however, about twice as high in reticular lesions as compared with the atrophic form. Many FoxP3+CD4+ T cells expressed T-bet, the hallmark transcription factor for IFN-γ-producing T cells, indicating that they may enhance immune and inflammatory responses rather than suppress them. Conclusions The absence of actively suppressing FoxP3+CD4+ T cells may in part explain why OLP is a remarkably persisting condition, in spite of the presence of substantially high numbers of FoxP3+CD4+ T cells. The findings emphasize that it is crucial to examine not only numbers but also functional phenotype of FoxP3+CD4+ T cells in human tissues.

Significance B and T lymphocytes collaborate during immune responses to antigens. B cells use membrane-bound antibody as part of their antigen receptor while T cells use a different receptor that recognizes antigen fragments bound to MHC molecules. We show here that T cells can recognize the variable parts of the B cell receptor when these are presented on MHC molecules. A prerequisite for such receptor cross-talk is that the B cell receptor binds antigen. The cross-talk results in collaboration between B and T cells and production of antibodies directed against the antigen. The findings have implications for basic immune regulation. The results may also help us understand the mechanism behind the development of SLE-like autoimmune diseases and B cell lymphomas., The B cell receptors (BCRs) for antigen express variable (V) regions that are enormously diverse, thus serving as markers on individual B cells. V region-derived idiotypic (Id) peptides can be displayed as pId:MHCII complexes on B cells for recognition by CD4+ T cells. It is not known if naive B cells spontaneously display pId:MHCII in vivo or if BCR ligation is required for expression, thereby enabling collaboration between Id+ B cells and Id-specific T cells. Here, using a mouse model, we show that naive B cells do not express readily detectable levels of pId:MHCII. However, BCR ligation by Ag dramatically increases physical display of pId:MHCII, leading to activation of Id-specific CD4+ T cells, extrafollicular T–B cell collaboration and some germinal center formation, and production of Id+ IgG. Besides having implications for immune regulation, the results may explain how persistent activation of self-reactive B cells induces the development of autoimmune diseases and B cell lymphomas.

Streptococcus pneumoniae is a bacterial pathogen that causes various diseases of public health concern worldwide. Current pneumococcal vaccines target the capsular polysaccharide surrounding the cells. However, only up to 13 of more than 90 pneumococcal capsular serotypes are represented in the current conjugate vaccines. In this study, we used two experimental approaches to evaluate the potential of Streptococcus mitis, a commensal that exhibits immune cross-reactivity with S. pneumoniae, to confer protective immunity to S. pneumoniae lung infection in mice. First, we assessed the immune response and protective effect of wild-type S. mitis against lung infection by S. pneumoniae strains D39 (serotype 2) and TIGR4 (serotype 4). Second, we examined the ability of an S. mitis mutant expressing the S. pneumoniae type 4 capsule (S. mitis TIGR4cps) to elicit focused protection against S. pneumoniae TIGR4. Our results showed that intranasal immunization of mice with S. mitis produced significantly higher levels of serum IgG and IgA antibodies reactive to both S. mitis and S. pneumoniae, as well as enhanced production of interleukin 17A (IL-17A), but not gamma interferon (IFN-γ) and IL-4, compared with control mice. The immunization resulted in a reduced bacterial load in respiratory tissues following lung infection with S. pneumoniae TIGR4 or D39 compared with control mice. With S. mitis TIGR4cps, protection upon challenge with S. pneumoniae TIGR4 was superior. Thus, these findings show the potential of S. mitis to elicit natural serotype-independent protection against two pneumococcal serotypes and to provide the benefits of the well-recognized protective effect of capsule-targeting vaccines. IMPORTANCE Streptococcus pneumoniae causes various diseases worldwide. Current pneumococcal vaccines protect against a limited number of more than 90 pneumococcal serotypes, accentuating the urgent need to develop novel prophylactic strategies. S. pneumoniae and the commensal Streptococcus mitis share immunogenic characteristics that make S. mitis an attractive vaccine candidate against S. pneumoniae. In this study, we evaluated the potential of S. mitis and its mutant expressing pneumococcal capsule type 4 (S. mitis TIGR4cps) to induce protection against S. pneumoniae lung infection in mice. Our findings show that intranasal vaccination with S. mitis protects against S. pneumoniae strains D39 (serotype 2) and TIGR4 (serotype 4) in a serotype-independent fashion, which is associated with enhanced antibody and T cell responses. Furthermore, S. mitis TIGR4cps conferred additional protection against S. pneumoniae TIGR4, but not against D39. The findings highlight the potential of S. mitis to generate protection that combines both serotype-independent and serotype-specific responses.

Streptococcus mitis is a colonizer of the oral cavity and the nasopharynx, and is closely related to Streptococcus pneumoniae. Both species occur in encapsulated and unencapsulated forms, but in S. mitis the role of the capsule in host interactions is mostly unknown. Therefore, the aim of this study was to examine how capsule expression in S. mitis can modulate interactions with the host with relevance for colonization. The S. mitis type strain, as well as two mutants of the type strain, an isogenic capsule deletion mutant, and a capsule switch mutant expressing the serotype 4 capsule of S. pneumoniae TIGR4, were used. Wild-type and capsule deletion strains of S. pneumoniae TIGR4 were included for comparison. We found that capsule production in S. mitis reduced adhesion to oral and lung epithelial cells. Further, exposure of oral epithelial cells to encapsulated S. mitis resulted in higher interleukin-6 and CXCL-8 transcription levels relative to the unencapsulated mutant. Capsule expression in S. mitis increased the sensitivity to human neutrophil peptide 1-3 but reduced the sensitivity to human β-defensin-3 and cathelicidin. This was in contrast with S. pneumoniae in which capsule expression has been generally associated with increased sensitivity to human antimicrobial peptides (AMPs). Collectively, these findings indicate that capsule expression in S. mitis is important in modulating interactions with epithelial cells, and is associated with increased or reduced susceptibility to AMPs depending on the nature of the AMP.

Current vaccines against Streptococcus pneumoniae, a bacterial species that afflicts people by causing a wide spectrum of diseases, do not protect against all pneumococcal serotypes. Thus, alternative vaccines to fight pneumococcal infections that target common proteins are under investigation. One promising strategy is to take advantage of immune cross-reactivity between commensal and pathogenic microbes for cross-protection. In this study, we examined the antibody-mediated cross-reactivity between S. pneumoniae and Streptococcus mitis, a commensal species closely related to S. pneumoniae. Western blot analysis showed that rabbit antisera raised against S. mitis reacted with multiple proteins of virulent S. pneumoniae strains (6B, TIGR4, and D39). Rabbit anti-S. pneumoniae IgG antibodies also showed binding to S. mitis antigens. Incubation of rabbit antisera raised against S. mitis with heterologous or homologous bacterial lysates resulted in marked inhibition of the developments of bands in the Western blots. Furthermore, plasma IgG antibodies from adult human volunteers intranasally inoculated with S. pneumoniae 6B revealed enhanced S. mitis-specific IgG titers compared with the pre-inoculation samples. Using an on-chip protein microarray representing a number of selected membrane and extracellular S. pneumoniae proteins, we identified choline-binding protein D (CbpD), cell division protein (FtsH), and manganese ABC transporter or manganese-binding adhesion lipoprotein (PsaA) as common targets of the rabbit IgG antibodies raised against S. mitis or S. pneumoniae. Cumulatively, these findings provide evidence on the antibody-mediated cross-reactivity of proteins from S. mitis and S. pneumoniae, which may have implications for development of effective and wide-range pneumococcal vaccines.

Thymic stromal lymphopoietin (TSLP) has multifaceted immunological functions ranging from maintenance of tolerance to induction of disease. Two human transcript variants of TSLP are described: a long form (variant 1; lfTSLP) consisting of four exons and an alternative, short form (variant 2; sfTSLP) that lacks two exons compared with variant 1. SfTSLP has not been described at the protein level or functionally studied. Here, we demonstrate that the human sfTSLP is the predominant form of TSLP, constitutively expressed at the mRNA and protein level in keratinocytes of oral mucosa and skin and in salivary glands, is released in saliva, and is not regulated in the same manner as the long form. Compared with lfTSLP, sfTSLP exhibits a markedly stronger antibacterial activity. Synthetic sfTSLP did not activate signal transducer and activator of transcription 5 (STAT5) signaling in CD1c(+) dendritic cells nor interfered with STAT5 activation by lfTSLP. SfTSLP may, therefore, act as an antimicrobial peptide in the oral cavity and on the skin to create a defense barrier that aids in the control of both commensal and pathogenic microbes. The results show that the two translational products of the TSLP gene have a different expression and different biological properties, and emphasize the importance of analyzing the two TSLP isoforms separately.

Current vaccines against Streptococcus pneumoniae, a bacterial species that afflicts people by causing a wide spectrum of diseases, do not protect against all pneumococcal serotypes. Thus, alternative vaccines to fight pneumococcal infections that target common proteins are under investigation. One promising strategy is to take advantage of immune cross-reactivity between commensal and pathogenic microbes for cross-protection. In this study, we examined the antibody-mediated cross-reactivity between S. pneumoniae and Streptococcus mitis, a commensal species closely related to S. pneumoniae. Western blot analysis showed that rabbit antisera raised against S. mitis reacted with multiple proteins of virulent S. pneumoniae strains (6B, TIGR4, and D39). Rabbit anti-S. pneumoniae IgG antibodies also showed binding to S. mitis antigens. Incubation of rabbit antisera raised against S. mitis with heterologous or homologous bacterial lysates resulted in marked inhibition of the developments of bands in the Western blots. Furthermore, plasma IgG antibodies from adult human volunteers intranasally inoculated with S. pneumoniae 6B revealed enhanced S. mitis-specific IgG titers compared with the pre-inoculation samples. Using an on-chip protein microarray representing a number of selected membrane and extracellular S. pneumoniae proteins, we identified choline-binding protein D (CbpD), cell division protein (FtsH), and manganese ABC transporter or manganese-binding adhesion lipoprotein (PsaA) as common targets of the rabbit IgG antibodies raised against S. mitis or S. pneumoniae. Cumulatively, these findings provide evidence on the antibody-mediated cross-reactivity of proteins from S. mitis and S. pneumoniae, which may have implications for development of effective and wide-range pneumococcal vaccines.

Commensal microbes are currently in the limelight in biomedical research because they play an important role in health and disease. Humans harbor an enormous diversity of commensals in various parts of the body, including the gastrointestinal and respiratory tracts. Advancement in metagenomic and other omic approaches, and development of suitable animal models have provided an unprecedented appreciation into the diversity of commensals, and the intricacies of their intimate communication with the host immune system. Most studies have focused on the host-commensal interaction in the gut, while less is known on this relationship in other sites of the body, such as the respiratory tract. In this article, we review emerging data from human and animal studies on the host responses to respiratory commensals, immune cross-reactivity between commensals and pathogens, and use of commensals as a vaccine delivery system. A better understanding of the delicate interplay between commensals and host may aid in efforts to develop effective vaccines and therapeutics.

Streptococcus mitis colonizes all niches of the human oral cavity from early infancy and throughout life. Monocytes patrol blood vessels, lymphoid and non-lymphoid tissues and migrate into infected tissue where they participate in the inflammatory cascade and immune regulation. Here, we studied the effect of S. mitis on monocytes. Transcriptome analysis of monocytes exposed to S. mitis (SmMo) revealed increased transcription of chemotactic factors (CCL2, CCL3, CCL20, CXCL1, CXCL2) and cytokines (IL1A, IL1B, IL6, IL23, IL36G, TNF), indicating that S. mitis may trigger recruitment of leucocytes and initiate inflammation. Increased transcription in SmMo of IL1B, IL6 and IL23 indicated that S. mitis may participate in the induction of Th17 responses and agreed with our earlier findings of S. mitis-mediated memory Th17 reactivity. Furthermore, S. mitis inhibited tetanus toxoid-specific CD4 T cell proliferation. This can be due to the increased secretion of IL-10 and expression of PD-L1 that was observed in SmMo. PGE2 can modulate IL-10 and PD-L1 expression, concomitant with that of CCR7, IL-12 and IL-23 that also were changed. This, along with increased SmMo transcription of PTGS2 (COX2) and PTGER4 (EP4), pointed to a role of PGE2. Measurement of PGE2 secretion by SmMo showed indeed a marked increase, and chemical inhibition of PGE2 production lowered the PD-L1 expression on SmMo. In conclusion, our findings show that S. mitis may trigger immune modulation by recruiting immune cells to the site of infection, while at the same time dampening the severity of the response through expression of IL-10, PGE2 and PD-L1.

Streptococcus mitis (S. mitis) is a pioneer commensal bacterial species colonizing many of the surfaces of the oral cavity in healthy individuals. Yet, not much information is available regarding its interaction with the host. We used examination of its transcriptional regulation in oral keratinocytes to elucidate some of its potential roles in the oral cavity. Transcription factor analysis of oral keratinocytes predicted S. mitis-mediated activation of aryl hydrocarbon receptor (AhR). Activation and functionality of AhR was confirmed through nuclear translocation determined by immunofluorescence microscopy and real-time polymerase chain reaction with reverse transcription analysis of CYP1A1, the hallmark gene for AhR activation. Addition of Streptococcus mutans or Streptococcus gordonii did not induce CYP1A1 transcription in the keratinocyte cultures. Introduction of an AhR-specific inhibitor revealed that S. mitis-mediated transcription of CXCL2 and CXCL8 was regulated by AhR. Elevated levels of prostaglandin E2 (enzyme-linked immunosorbent assay) in supernatants from S. mitis-treated oral epithelial cells were also attenuated by inhibition of AhR activity. The observed AhR-regulated activities point to a contribution of S. mitis in the regulation of inflammatory responses and thereby to wound healing in the oral cavity. The concept that the oral commensal microbiota can induce AhR activation is important, also in view of the role that AhR has in modulation of T-cell differentiation and as an anti-inflammatory factor in macrophages.

Chronic periodontitis (CP) and atherosclerotic and aortic aneurysmal vascular diseases (VD) are inflammatory conditions that share a number of predisposing factors. They have a complex genetic heritability and may share genetic risk factors, but a well-defined relationship is still not determined. In addition, distinct genetic patterns of predisposition have been associated with these diseases. Here, we investigated the association of polymorphisms in the IL-1 gene locus with CP in a case-case study analysing VD patients with or without CP. Seventy-four patients with VD of whom 36 had CP were genotyped for single nucleotide polymorphisms in the IL1A -889 (rs1800587), IL1B +3954 (rs1143634) and IL1B at -511 (rs16944) genes and for VNTR polymorphisms in the IL1RN gene. A significantly higher frequency (17%) for allele 1 (four repeats) of the IL1RN VNTR gene was found among the VD patients with CP compared to those without CP. In addition, the frequency of the IL1RN VNTR genotypes 1/1 (4/4 repeats) and 2/2 (2/2 repeats) were significantly higher and lower, respectively, in VD patients with CP. These findings suggest an association of genetic polymorphisms in the IL1-gene locus with risk for CP in patients with VD. The carriage of the risk genotypes, the development and the subsequent influence of CP on systemic health may constitute an additional burden in the pathogenesis of VD. This emphasizes the importance of effective periodontal treatment in patients with VD.

Nerve growth factor (NGF) and its different precursor forms are secreted into human saliva by salivary glands and are also produced by an array of cells in the tissues of the oral cavity. The major forms of NGF in human saliva are forms of pro-nerve growth factor (pro-NGF) and not mature NGF. The NGF receptors tropomyosin-related kinase A (TrkA) and p75 neurotrophin receptor (p75NTR) are widely expressed on cells in the soft tissues of the human oral cavity, including keratinocytes, endothelial cells, fibroblasts and leukocytes, and in ductal and acinar cells of all types of salivary glands. In vitro models show that NGF can contribute at most stages in the oral wound healing process: restitution, cell survival, apoptosis, cellular proliferation, inflammation, angiogenesis and tissue remodeling. NGF may therefore take part in the effective wound healing in the oral cavity that occurs with little scarring. As pro-NGF forms appear to be the major form of NGF in human saliva, efforts should be made to study its function, specifically in the process of wound healing. In addition, animal and clinical studies should be initiated to examine if topical application of pro-NGF or NGF can be a therapy for chronic oral ulcerations and wounds.

Objective Epithelial cells participate in wound healing by covering wounds, but also as important mediators of wound healing processes. Topical application of the phospholipid growth factor lysophosphatidic acid (LPA) accelerates dermal wound healing and we hypothesized that LPA can play a role in human oral wound healing through its effects on human oral keratinocytes (HOK). Design HOK were isolated from gingival biopsies and exposed to LPA. The LPA receptor profile, signal transduction pathways, gene expression and secretion of selected cytokines were analyzed. Results HOK expressed the receptors LPA 1 , LPA 5 and LPA 6 and LPA activated the ERK1/2, JNK and p38 intracellular pathways, substantiated by secretion of IL-6 and IL-8. The early (2 h) and intermediate (6 h) gene expression profiles of HOK after LPA treatment showed a wide array of regulated genes. The majority of the strongest upregulated genes were related to chemotaxis and inflammation, and became downregulated after 6 h. At 6 h, genes coding for factors involved in extracellular matrix remodeling and re-epithelialization became highly expressed. IL-36γ, not earlier known to be regulated by LPA, was strongly transcribed and translated but not secreted. Conclusions After stimulation with LPA, HOK responded by regulating factors and genes that are essential in wound healing processes. As LPA is found in saliva and is released by activated cells after wounding, our results indicate that LPA has a favorable physiological role in oral wound healing. This may further point towards a beneficial role for application of LPA on oral surgical or chronic wounds.

Nerve growth factor (NGF) is a pluripotent mediator that is present in a range of human tissues. Nerve growth factor was originally considered important only in neuronal homeostasis and pathophysiology, but later it was also implicated in the pathophysiology of inflammation, epithelial differentiation, and wound healing. In this study, the distribution of nerve growth factor beta (NGF-β) and pro-NGF, and their receptors - tyrosine kinase A (TrkA) and p75(NTR) - was examined in human parotid, submandibular, sublingual, and labial salivary glands by immunohistochemistry. Intercalated, striated, and collecting-ducts in all gland types showed strong staining for pro-NGF but only weak cytoplasmic or sparse nuclear staining for NGF-β. Tyrosine kinase A was strongly expressed in the ducts of all gland types, whereas p75(NTR) expression was mainly confined to collecting ducts. In acini, no or only weak cytoplasmic staining was found for all markers, and some nuclei stained positive for NGF-β, pro-NGF, and TrkA. Western blotting of saliva showed secretion of several forms of pro-NGF, while no mature NGF-β was detected. Salivary pro-NGF may play a role in oral wound healing.

Observational studies indicate that chronic periodontal disease is associated with adverse cardiovascular outcomes. The aim of this study was to determine whether initial periodontal treatment has a beneficial effect on systemic markers of inflammation and cardiovascular risk. One hundred and thirty-six adults with chronic periodontitis were allocated to either intervention or control groups in a 3-month randomized controlled intervention study. The intervention group received initial periodontal treatment, whereas the control group did not receive that treatment until after the study. Blood levels of cardiovascular risk factors, and of hematological, inflammatory, and metabolic markers, were measured at the beginning and the end of the study, and differences were calculated. Fibrinogen level was the primary outcome measure. Data for 61 persons in the intervention group and for 64 persons in the control group were available for statistical analysis. Compared with the control group, the intervention group showed a non-significant trend for a lower fibrinogen level. Significant increases in hemoglobin and hematocrit were seen after treatment, showing that initial periodontal treatment, a relatively simple and cost-effective intervention, has systemic effects.

Serum IgG1, IgG2, IgG3 and IgG4 antibody levels directed against lipopolysaccharide (LPS) from Bacteroides gingivalis were measured in the sera from systemically healthy subjects with and without periodontitis. An enzyme-linked immunosorbent assay was used that included coating of microtiter plates with LPS, and subsequent incubation with patient sera followed by mouse monoclonal subclass-specific antibodies, biotinylated sheep anti-mouse IgG and alkaline phosphatase conjugated to streptavidin. Anti-LPS IgG antibodies were dominated by IgG2, and moderate amounts only of IgG1, IgG3 and IgG4 were found. The periodontitis patients had significantly higher anti-LPS IgG1, IgG2 and IgG3 levels when compared to the subjects with healthy periodontium (p less than 0.05, Mann-Whitney test).

Polymorphisms in the interleukin-1 (IL1) gene have been suggested to influence transcription of IL1A (interleukin-1α) and IL1B (interleukin-1β) and thereby the pathophysiology of periodontitis. This case-control association study on 415 northern European Caucasian patients with aggressive periodontitis (AgP) and 874 healthy controls was conducted to examine 10 single-nucleotide polymorphisms (SNPs) in the genes of the IL1 cluster for association with IL1A, IL1B, CKAP2L (cytoskeleton-associated protein 2-like), and IL1RN (IL-1 receptor antagonist). The results do not support an association between variants in the IL1 gene cluster and AgP. This case-control study had at least 95% power to detect genuine associations with variants carrying relative risks of at least 1.5 for heterozygous carriers and 2.25 for homozygous carriers. Previous reports of an association between IL1 promoter SNPs and periodontitis might reflect subpopulation effects and have to be interpreted with care.

Aims To evaluate the expression of p75 neurotrophin receptor (p75(NTR)) in oral squamous cell carcinoma (OSCC). The results were related to tumour node metastasis (TNM) stage, World Health Organization (WHO) grade, invasive front grading (IFG) and prognosis. Methods and results Immunohistochemically, the expression of p75(NTR) was assessed in 53 T1-T2 OSCCs. Clinical data were recorded prospectively. The end-point was disease-free survival. All tumours expressed p75(NTR), and this expression, both in central/superficial tumour areas and at the invasive front, was associated with poor prognosis (P = 0.03 and P = 0.02) (log rank test). Tumours with marked cellular dissociation (IFG parameter) had more recurrences than tumours with collective tumour cell invasion (P = 0.03). In tumours showing both p75(NTR) at the invasive front and marked tumour cell dissociation, the average risk of recurrence was increased about 17 times (Cox regression analysis) compared with tumours with low p75(NTR) expression and collective invasion. Traditional prognostic systems were of no prognostic significance. Conclusion p75(NTR) was expressed in all OSCCs. p75(NTR) expression and the pattern of invasion were significantly associated with a poor prognosis in OSCCs, and both were better prognostic factors than traditional prognostic parameters. The combination of p75(NTR) expression and the pattern of invasion strongly increased precision in the identification of tumours with poor disease-free survival.

The T-cell specific adapter protein (TSAd) encoded by the SH2D2A gene is up-regulated in activated human CD4+ T-cells in a cAMP-dependent manner. Expression of SH2D2A is important for proper activation of T-cells. Here, we show that SH2D2A expression is regulated both at the transcriptional and translational level. cAMP signaling alone induces TSAd-mRNA expression but fails to induce increased TSAd protein levels. By contrast, TCR engagement provides signals for both TSAd transcription and translation. We further show that cAMP signaling can prime T-cells for a more prompt expression of TSAd protein upon TCR stimulation. Our study thus points to a novel mechanism for how cAMP signaling may modulate T-cell activation through transcriptional priming of resting cells.

Trefoil factor 3 (TFF3) is a member of the mammalian TFF family. Trefoil factors are secreted onto mucosal surfaces of the entire body and exert different effects according to tissue location. Trefoil factors may enhance mucosal healing by modulating motogenic activity, inhibiting apoptosis, and promoting angiogenesis. Trefoil factor 3 is secreted from the submandibular gland and is present in whole saliva. The aim of this study was to assess the migratory and proliferative effects of TFF3 on primary oral human keratinocytes and oral cancer cell lines. The addition of TFF3 increased the migration of both normal oral keratinocytes and the cancer cell line D12, as evaluated by a two-dimensional scratch assay. By contrast, no increase in proliferation or energy metabolism was observed after stimulation with TFF3. Trefoil factor 3-enhanced migration was found to be driven partly by the extracellular signal-related kinase (Erk1/2) pathway, as shown by addition of the mitogen-activated protein kinase (MAPK) inhibitor PD 98059. Previous functional studies on trefoil peptides have all been based on cells from monolayered epithelium like the intestinal mucosa; this is the first report to show that normal and cancerous keratinocytes from stratified epithelium respond to TFF stimuli. Taken together, salivary TFF3 is likely to contribute to oral wound healing.

Background: Nerve growth factor (NGF) can through its receptors TrkA and p75NTR convey signals for cell survival, differentiation and death. The aim of this study was to examine whether NGF can play a role in the pathology of oral lichen (OL). Methods: Sections from biopsies taken from patients with erythematous (ERY) OL and from volunteers with normal oral mucosa (NOM) were immunostained with antibodies against NGF, proNGF, TrkA, phosphorylated Trk, p75NTR and phosphorylated Akt (pAkt) and expression of RNA coding for proNGF/NGF was investigated by in situ hybridization. Results: Both in ERY OL and NOM, cytoplasmic staining for NGF was seen in granular and upper spinous cell layers of the epithelium, whereas proNGF staining was seen in all epithelial cell layers. In situ hybridization showed that the proNGF protein was produced in the same cell layers. In OL, strong cytoplasmic stainings for TrkA and activated Trk (pTrk) were observed in all epithelial cell layers while these stainings were only weak in NOM. Basal keratinocytes in OL showed no or only weak cytoplasmic staining for p75NTR, but in NOM there was a clear cell membrane staining. In OL, strong cytoplasmic and intermittent nuclear staining for pAkt was observed in spinous, granular and superficial layers, while basal and parabasal keratinocytes were negative. This staining was weak or absent in the entire epithelium of NOM. Conclusions: TrkA upregulation and activation in OL is one of the pathways that can activate pAkt and thereby rescue epithelial cells from untimely cell death.

Oral keratinocytes are connected via cell-to-cell adhesions to protect underlying tissues from physical and bacterial damage. Lysophosphatidic acids (LPAs) are a family of phospholipid mediators that have the ability to regulate gene expression, cytoskeletal rearrangement, and cytokine/chemokine secretion, which mediate proliferation, migration, and differentiation. Several forms of LPA are found in saliva and gingival crevicular fluid, but it is unknown how they affect human oral keratinocytes (HOK). The aim of the present study was therefore to examine how different LPA forms affect the expression of adhesion molecules and the migration and proliferation of HOK. Keratinocytes were isolated from gingival biopsies obtained from healthy donors and challenged with different forms of LPA. Quantitative real-time RT-PCR, immunocytochemistry, and flow cytometry were used to analyze the expression of adhesion molecules. Migration and proliferation assays were performed. Lysophosphatidic acids strongly promoted expression of E-cadherin and occludin mRNAs and translocation of E-cadherin protein from the cytoplasm to the membrane. Occludin and claudin-1 proteins were up-regulated by LPA. Migration of HOK in culture was increased, but proliferation was reduced, by the addition of LPA. This indicates that LPA can have a role in the regulation of the oral epithelial barrier by increasing the expression of adhesion molecules of HOK, by promotion of migration and by inhibition of proliferation.

Objectives: Limited attention has been given to the role mast cells may play in periodontal diseases. Background: Mast cells are indeed found abundantly below and within several types of mucosal epithelia. On the basis oftheir proteinase content, mast cells are divided into connective tissue (CT) and mucosal phenotypes. The CT phenotype contains both tryptase and chymase (MC T C ), while the mucosal phenotype contains only tryptase (MC T ). The in vivo significance of different mast cell phenotypes has not yet been fully established. Mast cells are able to phagocytose, process and present antigens as effectively as macrophages. Results: Recently mast cells were found in high numbers in chronically inflamed gingival tissue taken from patients with chronic marginal periodontitis (CMP). The number of mast cells was found to be even higher in HIV + patients with CMP. Furthermore, mast cells also express strongly matrix metalloproteinases (MMPs), which are key enzymes in degradation of gingival extracellular matrix. Mast cells may release preformed cytokines directing local innate and adaptive immune responses. The present review will focus on possible roles for mast cells in periodontal diseases. Conclusions: We certainly feel that this is a key cell in inflamed periodontal tissue and its role in periodontitis needs to be revisited.

Background: In situ detection of DNA fragmentation by TdT (terminal deoxynucleotidyl transferase)-mediated dUTP nick end labeling (TUNEL) is a widely used technique to identify apoptotic cells in the terminal phases of cell death. Several studies have shown that there are statistically increased numbers of TUNEL+ cells within the epithelium of oral lichen (OL). It was suggested that this indicates an increased rate of apoptosis among basal and suprabasal keratinocytes in OL epithelium. The aim of this study was to identify the TUNEL+ cells in the epithelium of erythematous (ERY) OL and normal oral mucosa (NOM). Methods: Sections of biopsies from NOM and ERY OL were processed for TUNEL combined with immunostaining for pan-cytokeratin or for cell markers specifically expressed by different leukocytes. Results: In NOM, TUNEL+ keratinocytes were almost exclusively seen in the outermost epithelial layers. This labeling was absent in ERY OL. In the basal and lower spinous layers, more TUNEL+ cell nuclei were seen in ERY OL as compared with NOM, in accordance with previous studies. The present observations show, however, that only very few of these cells were keratinocytes, but rather were CD4+ lymphocytes and CD68+ macrophages. There was no difference between the numbers of TUNEL+ keratinocytes in basal and lower spinous layers in ERY OL and NOM epithelium. No intraepithelial CD8+ lymphocytes, Langerhans cells, or mast cells were found to be TUNEL+. Conclusion: The findings indicate that the pathologic changes in ERY OL epithelium cannot be explained by increased prevalence of terminal keratinocyte cell death identified by TUNEL.

Background: Mast cells are a prominent cell type in the gingival infiltrate in periodontitis. In this study we examined the expression by gingival mast cells of matrix metalloproteinases, MMP-1, MMP-2, MMP-8 and the tissue inhibitors of metalloproteinases, TIMP-1 and TIMP-2. Methods: Gingival specimens from 12 human immunodeficiency virus-negative (HIV–) and 15 HIV-positive (HIV+) patients with chronic marginal periodontitis (CMP), and from 10 HIV– and four HIV+ controls with clinically healthy gingiva (HG) were examined after double immunofluorescence staining for mast cell tryptase, combined with antibodies for MMP-1, MMP-2, MMP-8 or their inhibitors TIMP-1 and TIMP-2. Results: In the HIV+CMP, HIV+HG and HIV–CMP groups, all mast cells expressed MMP-1 and MMP-8, whereas a smaller proportion (40–60%) in the HIV–HG controls displayed such staining. The former groups also displayed a significantly higher proportion (39–64%) of mast cells expressing MMP-2 as compared with the HIV–HG group (21–31%). All groups displayed similar proportions of TIMP-1 expressing mast cells (86–100%), whereas significantly increased proportions of TIMP-2+ mast cells were seen in the HIV+CMP, HIV+HG and HIV–CMP groups (18–25%) as compared with the HIV–HG group (8–13%). Mast cells were the cell type that most prominently expressed MMP-1 and MMP-8. MMP-2 expression was also strong in mast cells, but was also similarly expressed in other cell types. Conclusion: The chronically inflamed periodontal lesions in the present study appeared with little evidence of mast cell degranulation. The results show, however, that mast cells in inflamed gingiva have the potential to degrade extracellular matrix if appropriately triggered.

Chronic marginal periodontitis is an inflammatory condition in which the supporting tissues of the teeth are destroyed. Interferon (IFN)-gamma is a cytokine that plays a pivotal role in the defense against infection, and mutations in the gene coding for the ligand binding chain (alpha, R1) of the IFN-gamma receptor (IFNGR1) confer suseptibility on infections caused by poorly virulent mycobacteria. Using an intronic (CA)n polymorphic microsatellite marker within the IFNGR1 gene we investigated whether genetic polymorphisms are associated with periodontitis. In 62 periodontitis patients and 56 healthy controls we found a total of 13 polymorphisms, 11 of which were found in the periodontitis patients and 9 in the controls. Although we observed a trend towards an association with disease for allele 192, there were no significant differences in allele frequency between patients and controls. We therefore cannot find any evidence to suggest that IFNGR1, as a single dominant gene, contributes to susceptibility to periodontitis. However, in combination with the environmental risk factor, smoking, the same allelic marker was significantly associated [OR = 5.56 (1.16OR36.31), P=0.014, Pcorr=0.027] with periodontitis. Our results support the multigene-environment interaction model of disease susceptibility to periodontitis.

When injected subcutaneously, mouse plasmacytoma (MOPC315) grew rapidly in situ, and metastatic cells became detectable first in the lymph nodes (LNs) and bone marrow, and later in the liver and lungs. We studied MOPC315 cell migration by tracking metastatic cells labelled with green fluorescent protein (GFP). We measured the levels of their chemokine receptor mRNA (by semiquantitative and real-time quantitative reverse transcriptase-polymerase chain reaction (RT-PCR), because chemokines can regulate organ predilection of metastasis. Freshly sorted metastatic cells and tumour cell lines derived from the liver of BALB/c mice overexpressed functional CCR6 and CCR7 molecules compared with primary tumour. Preincubation with the CCR6 ligand (CCL20) induced liver-sorted tumour cells to preferentially colonize the liver, demonstrating an association between liver metastasis and CCR6 expression in the mouse. Because the liver is a common site for metastasis, second only to draining LNs, we wished to ascertain whether this finding could be generalized, i.e. whether other cancers can use the similar mechanism of metastasis to the liver, and whether it holds true for humans. We found that CCR6 is overexpressed in small liver metastases of colon, thyroid and ovarian carcinomas compared with normal liver. Because human liver constitutively expresses CCL20, it could attract and select CCR6+ cancer cells. We suggest that chemotaxis via CCR6 might be a common mechanism by which malignant cancers metastasize to the liver. As metastasis in patients with cancer poses the biggest peril for survival, inhibition of CCR6 signalling, either during or after medical or surgical treatment, might be useful in preventing liver metastasis.

Background: Common clinical forms of oral lichen planus (OLP) and oral lichenoid reactions (OLR) are erythematous (ERY) or reticular (RET). The purpose of this study was to find histopathological changes that differ between these forms. Methods: Epithelial thickness, epithelial proliferation rate, apoptosis, and HLA-DR expression were compared among 10 reticular and 12 erythematous lesions, and 11 normal oral mucosa samples (NOM). Results: The epithelium in ERY was thinner than in NOM, whereas RET showed values between ERY and NOM. Cell proliferation increased significantly in ERY as compared with RET and NOM, with no difference between RET and NOM. Relative numbers of epithelial cell nuclei displaying visible chromatin condensation were reduced in ERY form. Conclusions: The markedly increased cell proliferation in ERY supports the notion that this form displays a higher disease activity as compared to RET. It can therefore be important to study each disease form separately.

Persons who smoke display a less pronounced increase of gingival bleeding in the experimental gingivitis model as compared with non-smokers. The aim of the present study was to investigate whether this could partly be explained by differences in levels of parotid total secretory IgA (S-IgA) or parotid S-IgA reactive with selected oral microorganisms. Parotid saliva samples were obtained from 11 smoking and 14 non-smoking volunteers, at baseline, after 5 and 14 days of full mouth experimental gingivitis. Output levels of total S-IgA and of specific S-IgA reactive with cell extracts from Actinobacillus actinomycetemcomitans, Actinomyces naeslundii, Campylobacter rectus, Fusobacterium nucleatum, Porphyromonas gingivalis, Prevotella intermedia, Prevotella nigrescens, Peptostreptococcus micros, Streptococcus gordonii and Streptococcus mutans were determined in the samples by means of ELISA. Smokers and non-smokers were found to have similar output levels (microg/min) of total S-IgA, and the values did not significantly change during the experimental gingivitis trial. Parotid salivary outputs (units/min) of the bacteria-specific S-IgA at baseline and at days 5 and 14, were not different between smokers and non-smokers; no changes were observed during the experimental gingivitis trial. The present observations indicate that total S-IgA and bacteria-specific S-IgA in saliva are not main factors that can explain the less pronounced increase of gingival bleeding in the experimental gingivitis model in smokers as compared with non-smokers.

Background HIV infection increases susceptibility for marginal periodontitis, with horizontal and rapid loss of periodontal soft tissues and alveolar bone. Objectives To examine whether numbers, distribution and some properties of mast cells, neutrophils and macrophages are normal in chronically inflamed gingiva of HIV-positive patients. Methods Gingival biopsies were stained for mast cell tryptase and chymase, neutrophil elastase, CD68, human transforming growth factor beta(1), HLA-DR, Fc gamma RI, Fc gamma RII and Fc gamma RIII and calprotectin. Results Patients at all stages of HIV infection showed radically increased numbers of mast cells and neutrophils throughout the connective tissue, and of macrophages below the oral gingival epithelium (P Conclusion HIV infection is associated with increased numbers of mast cells, macrophages and neutrophils in the chronic periodontal lesion. This may predispose for tissue destruction through the release of inflammatory mediators and effector molecules. The unusually heavy cell infiltrate throughout the gingival connective tissue may contribute to the diverging pattern of periodontal tissue loss in HIV-positive patients.

Antigen-presenting cells (APCs) from subcutaneous mouse MOPC315 plasmacytoma phagocytosed immunoglobulin G–coated magnetic beads, enabling efficient isolation within 2 hours by magnetic separation (APC-MB). Cell morphology was heterogeneous, with some of the cells having dendrites. The surface phenotype of purified tumor APCs-MB was CD11b+, CD11c+, CD40+, CD80+, CD86+, and MHC class II+. Tumor APCs-MB expressed messenger RNA for fractalkine and ABCD-1 chemokines, and for CC-type chemokine receptors CCR5 and CCR7, indicating the presence of mature dendritic cells (DCs). Visualized at a single cell level within 4 hours after disruption of the tumor, APCs-MB induced rapid Ca++ mobilization in MHC class II–restricted tumor idiotype (Id)–specific cloned CD4+ T cells. In long-term assays, tumor APCs-MB induced proliferation of naive T cells from Id-specific T-cell receptor transgenic mice. The results suggest that tumor APCs-MB represent a heterogeneous cell population that includes myeloid-derived DCs of various stages of maturation. A considerable fraction (≥ 15%) of DCs is spontaneously primed with tumor-specific antigen.

Background: HIV-seropositive (HIV+) patients become increasingly susceptible to periodontal diseases as HIV infection proceeds. We have previously shown that HIV+ patients with chronic marginal periodontitis (CMP) have remarkably increased numbers of gingival plasma cells in the connective tissue underlying the oral gingival epithelium, but depressed specific serum IgG levels towards periodontopathogenic bacteria. Langerhans cells (LC) and keratinocytes (KC) are antigen-presenting cells that are important in promoting immune responses. Method: In this study we examined, by means of immunofluorescence, the distribution and numbers of LC and activated KC in biopsies taken from inflamed periodontal sites in HIV+, HIV− patients with CMP. Results: In the pocket epithelium in both patient groups, basal layer KC expressed HLA-DR molecules. In the oral gingival epithelium of HIV+ patients, basal layer KC also expressed HLA-DR molecules and numbers of LC were decreased as compared with HIV− persons. Conclusion: The findings suggest that the oral gingiva in HIV+ patients may be affected by inflammation.

Aims: In this study, we have examined the occurence of FcαRI-bearing cells in gingival tissue, gingival fluid and blood, in search for possible roles of IgA and FcαRI in periodontal lesions. Methods: Gingival biopsies from inflamed and healthy sites were obtained from patients with chronic marginal periodontitis. Sections of inflamed gingiva were examined by immunofluorescence techniques and compared to sections from healthy sites. Smears were made from blood and gingival crevicular fluid and similarly studied. Results: Dense infiltrates of neutrophils with strong expression of FcαRI (and FcγRIII) were found in connective tissue and epithelium of the apical part of periodontal pockets from diseased sites. In contrast, only few such cells were found in healthy gingiva from the same patients. Neutrophils in gingival fluid, tissue and blood expressed FcαRI with similar intensity, whereas the expression of FcγRIII was significantly decreased in gingival crevicular fluid. Considerable numbers of bacteria from gingival plaque were found to be covered by IgA. Conclusion: It is suggested that FcαRI on neutrophils may play an important role in elimination of IgA-opsonized bacteria, both in periodontal tissue and the adjacent pockets.

Multiple myelomas produce tumor-specific antigen (TSA) in the form of idiotype (Id) on monoclonal Ig. CD4+T cells can recognize Id-peptide on MHC class II molecules and protect against challenges with MOPC315 cells, which are, as common for myelomas, class II-negative. The present study explains these previous results by demonstrating that Id can be transferred from myeloma cells to antigen-presenting cells (APC), which present processed Id-peptide on their class II molecules to Id-specific T cell receptor-transgenic (TCR-TG) CD4+T cells. Id-primed tumor APC were heterogeneous, the majority being dendritic cells with class II+, CD11b+CD11c+CD40+CD80+CD86+markers. The APC were localized beneath CD31+endothelial cells of tumor microvessels, and their frequency declined with tumor progression. The APC could stimulate Id-specific naive TCR-TG, short-term polarized TCR-TG, and cloned CD4+T cells to proliferate and produce cytokinesin vitro. Furthermore, small MOPC315 tumors established in Id-specific TCR-TG mice contained clusters of activated (CD69+CD25+) and proliferating (BrdUrd+) Id-specific transgenic CD4+blasts. The activated Id-specific T cells were located adjacent to Id-primed dendritic cells in the tumor. Thus, a TSA can be transferredin vivofrom myeloma, and possibly other types of cancer cells to APC for MHC class II presentation to CD4+T cells.

Mycloma cells secrete monoclonal immunoglobulin (Ig), called myeloma protein. The variable (V) regions of myeloma proteins are unique to each plasma cell tumor, and therefore contain highly tumor-specific antigenic determinants called idiotopes (Id). T cells with specificity for Id are thought to be of importance in eradication of multiple myeloma. In ongoing clinical trials, myeloma patients are vaccinated against the Id of their own myeloma protein, with the aim of inducing Id-specific T cells. However, this strategy will only succeed if Id-specific T cells are present in patients, and are able to respond. In an experimental animal model, we have shown that [d-specific T cells become progressively deleted as the myeloma protein serum concentration exceeds 50 microg/ml. This indicates that the ability of multiple myeloma patients to respond to Id-vaccination might be seriously handicapped. We suggest that Id-vaccination should be reserved for eradication of minimal residual disease, e.g. after high-dose chemotherapy and stem-cell transplantation.