Several pathologies of the oral cavity have been associated with stress, so we investigated salivary-induced aggregation during psychological stress. In addition, salivary total protein, alpha-amylase, and secretory immunoglobulin A (s-IgA) were assessed. In this longitudinal study, 28 dental students provided unstimulated whole saliva during 10 minutes before an academic examination and subsequently 2 weeks and 6 weeks later in a nonstress situation. The effect of whole saliva on the aggregation of Streptococcus gordonii (HG 222) was determined spectrophotometrically. The results shows a significant stress-mediated increase of salivary total protein concentration, alpha-amylase activity, amylase/protein ratio, alpha-amylase output, s-IgA concentration, and s-IgA output. There was also a trend for increased total protein output, whereas salivary flow rate was unchanged. The aggregation of S. gordonii in whole saliva collected before examination was 13.1%, whereas the aggregation in whole saliva collected during nonstress was 23.3%. This reduction was statistically significant (p < .01). Furthermore, the decrease in bacterial aggregation was related to the increase in state-anxiety (p < .05). The reduction in aggregation of S. gordonii under stress was not correlated with changes in salivary flow rate, s-IgA concentration, total protein concentration, or alpha-amylase activity. These results suggest that acute psychological stress exerts its influence on both salivary composition and salivary function. Reduced bacterial aggregation may be a contributing factor in the often reported relationship between stress and impaired oral health.

The lung scavenger receptor-rich protein glycoprotein-340 (gp-340) is present in bronchoalveolar lavage (BAL) fluids and saliva and mediates specific adhesion to and aggregation of bacteria. It also binds to surfactant proteins A and D (SP-A and -D). Prior studies demonstrated that SP-A and SP-D contribute to innate defense against influenza A virus (IAV). We now show that lung and salivary gp-340 inhibit the hemagglutination activity and infectivity of IAV and agglutinate the virions through a mechanism distinct from that of SP-D. As in the case of SP-A, the antiviral effects of gp-340 are mediated by noncalcium-dependent interactions between the virus and sialic acid-bearing carbohydrates on gp-340. Gp-340 inhibits IAV strains that are resistant to SP-D. Concentrations of gp-340 present in saliva and BAL fluid of healthy donors are sufficient to bind to IAV and inhibit viral infectivity. On the basis of competition experiments using competing saccharide ligands, it appears that SP-D does not entirely mediate that anti-IAV activity of BAL fluid and contributes little to that of saliva. Furthermore, removal of gp-340 from BAL fluid and saliva significantly reduced anti-IAV activity. Hence, gp-340 contributes to defense against IAV and may be particularly relevant to defense against SP-D-resistant viral strains.

Deleted in Malignant Brain Tumors 1 (DMBT1) at chromosome region 10q25.3-q26.1 has been proposed as a candidate tumor-suppressor gene for brain, digestive tract, and lung cancer. Recent studies on its expression in lung cancer have led to divergent results and have raised a controversial discussion. Moreover, DMBT1 has been implicated with epithelial protection in the respiratory tract. We thus wondered how a loss of its expression could be related to carcinogenesis in the lung. To address these issues, we investigated the DMBT1 expression and location in the normal lung and lung cancer. By reverse-transcription PCR, a down-regulation of the DMBT1 expression in lung cancer cell lines is commonly detected. Immunohistochemical studies in situ demonstrate that there are also low steady-state levels of DMBT1 in the normal respiratory epithelium. However, an up-regulation takes place in the tumor-flanking epithelium and upon respiratory inflammation. Lung carcinomas show increased DMBT1 expression compared to that of undiseased lung tissue, but decreased DMBT1 levels compared to that of tumor-flanking and inflammatory tissue. A switch from a lumenal secretion to a secretion to the extracellular matrix takes place during lung carcinogenesis. Our data may resolve the controversial discussion on its expression in lung carcinomas. We hypothesize that the changes of the DMBT1 expression and location do reflect a time course that may point to possible mechanisms for its role in epithelial cancer.

No abstract

Salivary agglutinin is a 300-400 kDa salivary glycoprotein that binds to antigen B polypeptides of oral streptococci, thereby playing a role in their colonization and the development of caries. A mass spectrum was recorded of a trypsin digest of agglutinin. A dominant peak of 1460 Da was sequenced by quadrupole time-of-flight (Q-TOF) tandem MS. The sequence showed 100% identity with part of the scavenger receptor cysteine-rich ('SRCR') domain found in gp-340/DMBT1 (deleted in malignant brain tumours-1). The mass spectrum revealed 11 peaks with an identical mass as a computer-simulated trypsin digest of gp-340. gp-340 is a 340 kDa glycoprotein isolated from bronchoalveolar lavage fluid that binds specifically to lung surfactant protein-D. DMBT1 is a candidate tumour suppressor gene. A search in the human genome revealed only one copy of this gene. The molecular mass, as judged from SDS/PAGE and the amino acid composition of agglutinin, was found to be nearly identical with that of gp-340. It was shown by Western blotting that monoclonal antibodies against gp-340 reacted with salivary agglutinin, and monoclonals against agglutinin reacted with gp-340. It was demonstrated that gp-340 and agglutinin bound in a similar way to Streptococcus mutans and surfactant protein-D. Histochemically, the distribution of gp-340 in the submandibular salivary glands was identical with the agglutinin distribution, as shown in a previous paper [Takano, Bogert, Malamud, Lally and Hand (1991) Anat. Rec. 230, 307-318]. We conclude that agglutinin is identical with gp-340, and that this molecule interacts with S. mutans and surfactant protein-D.

Deleted in malignant brain tumors 1 (DMBT1) at 10q25.3-q26.1 has been proposed as a candidate tumor-suppressor gene for brain and epithelial cancer. DMBT1 encodes a multifunctional mucin-like protein presumably involved in epithelial differentiation and protection. The gene consists of highly homologous and repeating exon and intron sequences. This specifically applies to the region coding for the repetitive scavenger receptor cysteine-rich (SRCR) domains and SRCR-interspersed domains (SIDs) that constitutes the major part of the gene. This particular structure may previously have interfered with the delineation of DMBT1 alterations in cancer. Uncovering these, however, is of mechanistic importance. By a combined approach, we conducted a detailed mutational analysis, starting from a panel of 51 tumors, including 46 tumor cell lines and five primary tumors. Alterations in the repetitive region were present in 22/31 (71%) tumors that were investigated in detail. Six tumors showed presumably de novo mutations, among these three with point mutations in combination with a loss of heterozygosity. However, none of the alterations unambiguously would be predicted to lead to an inactivation of DMBT1. We define seven distinct DMBT1 alleles based on variable numbers of tandem repeats (VNTRs). At least 11 tumors exclusively harbored these VNTRs. The data suggest that the SRCR/SID region defines a complex multi-allele system that has escaped previous analyses and that represents the major basis for the variability of DMBT1 in cancer. DMBT1 thus compares to mucins rather than to conventional tumor suppressors.

Salivary agglutinin is a 300–400kDa salivary glycoprotein that binds to antigen B polypeptides of oral streptococci, thereby playing a role in their colonization and the development of caries. A mass spectrum was recorded of a trypsin digest of agglutinin. A dominant peak of 1460Da was sequenced by quadrupole time-of-flight (Q-TOF) tandem MS. The sequence showed 100% identity with part of the scavenger receptor cysteine-rich (‘SRCR’) domain found in gp-340/DMBT1 (deleted in malignant brain tumours-1). The mass spectrum revealed 11 peaks with an identical mass as a computer-simulated trypsin digest of gp-340. gp-340 is a 340kDa glycoprotein isolated from bronchoalveolar lavage fluid that binds specifically to lung surfactant protein-D. DMBT1 is a candidate tumour suppressor gene. A search in the human genome revealed only one copy of this gene. The molecular mass, as judged from SDS/PAGE and the amino acid composition of agglutinin, was found to be nearly identical with that of gp-340. It was shown by Western blotting that monoclonal antibodies against gp-340 reacted with salivary agglutinin, and monoclonals against agglutinin reacted with gp-340. It was demonstrated that gp-340 and agglutinin bound in a similar way to Streptococcus mutans and surfactant protein-D. Histochemically, the distribution of gp-340 in the submandibular salivary glands was identical with the agglutinin distribution, as shown in a previous paper [Takano, Bogert, Malamud, Lally and Hand (1991) Anat. Rec. 230, 307–318]. We conclude that agglutinin is identical with gp-340, and that this molecule interacts with S. mutans and surfactant protein-D.

Objective: Biochemical host defenses at mucosal sites, such as the oral cavity, play a key role in the regulation of microbial ecology and the prevention of infectious disease. These biochemical factors have distinct features, some of which benefit the host and some that benefit bacteria. We investigated the effects of acute stress on the salivary levels of the carbohydrate structure sulfo-Lewis a (sulfo-Le a ), which is linked to the mucosal glycoprotein MUC5B. Sulfo-Le a was recently identified as an adhesion molecule for Helicobacter pylori; therefore, we also measured saliva-mediated adherence (ex vivo) of H. pylori. The oral cavity is suspected to be involved in the transmission of H. pylori. Methods: Saliva was collected from 17 undergraduates before (baseline), during (stress), and after (recovery) exposure to a video showing surgical procedures. In addition, blood pressure, an impedance cardiogram, and an electrocardiogram were recorded. Results: During stressor exposure, participants reported increased state anxiety. In addition, stroke volume increased and heart rate decreased. The stressor induced a strong increase in salivary sulfo-Le a concentration (U/ml), sulfo-Le a output (U/min), sulfo-Le a /total protein ratio (U/mg protein), and saliva-mediated adherence (ex vivo) of H. pylori. As expected, sulfo-Le a concentration correlated with the adherence of H. pylori (r ϭ 0.72, p Ͻ .05). It was demonstrated that the observed adherence was induced by MUC5B and that the carbohydrate structure sulfo-Le a contributed to this process. Conclusions: Our study demonstrated a direct link between stress-mediated biochemical changes and altered host-microbe interactions in humans. Increased bacterial adherence may be a contributing factor in the observed relationship between stress and susceptibility to infectious disease.