New sensitive method for the measurement of lysozyme and lactoferrin to explore mucosal innate immunity. Part II: time-resolved immunofluorometric assay used in HIV patients with oral candidiasis

VEN-120, a Recombinant Human Lactoferrin, Promotes a Regulatory T Cell [Treg] Phenotype and Drives Resolution of Inflammation in Distinct Murine Models of Inflammatory Bowel Disease

BACKGROUND AND AIMS

Inflammatory bowel disease [IBD] is characterised by a disruption of immune homeostasis, which is tightly regulated to protect against harmful pathogens yet not react to commensal antigens. Animal studies indicate that regulatory T cells [Treg] modulate the immune response to prevent IBD development. Lactoferrin [LF] is an endogenous anti-inflammatory pleiotropic protein secreted at high concentrations in colostrum and at mucosal sites. However, the effect of LF on specific T lymphocyte populations has not been studied. Here, we identify a novel mechanism by which a recombinant human LF, VEN-120, regulates T cell populations in health and disease.

METHODS

Two murine models of intestinal inflammation, the dextran sodium sulphate colitis model and the TNFΔARE/+ model of ileitis, were used to study the anti-inflammatory and T cell modulating ability of VEN-120. Flow cytometry was used to evaluate T cell populations within the lamina propria and mesenteric lymph nodes, and to evaluate the effect of VEN-120 on CD4+ T cells in vitro.

RESULTS

VEN-120 reduced inflammation in both models of IBD, accompanied by increased Tregs in the intestinal lamina propria. Treatment of CD4+ T cells in vitro resulted in an upregulation of Treg genes and skewing towards a Treg population. This in vitro T cell skewing translated to an increase of Treg homing to the intestinal lamina propria and associated lymph tissue in healthy mice.

CONCLUSIONS

These data provide a novel immunological mechanism by which VEN-120 modulates T cells to restrict inflammatory T cell-driven disease.

Infection Transmission by Saliva and the Paradoxical Protective Role of Saliva

Saliva is produced by both major (parotid and submandibular and sublingual) and minor (located in the mouth) glands, with different constituents and properties between the two groups. In the mouth saliva is a colorless, odorless, tasteless, watery liquid containing 99% water and 1% organic and inorganic substances and dissolved gases, mainly oxygen and carbon dioxide. Salivary constituents can be grouped into proteins (e.g., amylase and lysozyme), organic molecules (e.g., urea, lipids, and glucose mainly), and electrolytes (e.g., sodium, calcium, chlorine, and phosphates). Cellular elements such as epithelial cells, leukocytes and various hormones, and vitamins have also been detected. The composition of saliva is modified, depending on factors such as secreted amount, circadian rhythm, duration and nature of stimuli, diet, and medication intake, among others.

Lactoferrin levels in gingival crevicular fluid and saliva of HIV-infected patients with chronic periodontitis

AIM

This study compared lactoferrin (LF) levels in the gingival crevicular fluid (GCF) and saliva between HIV-infected and noninfected patients with chronic periodontitis.

METHODS

For each subject, LF levels were analyzed in one shallow site (SS; PD ≤3 mm), one deep site (DS; PD >5 mm) and in resting whole saliva. Two groups, 28 HIV-infected and 10 noninfected, were selected.

RESULTS

Although the salivary LF levels were higher in HIV-infected than in noninfected individuals, especially in AIDS patients, this was not statistically significant (P > 0.05). Subgingival LF levels for SS and DS were lower among HIV-infected individuals, although AIDS patients showed the lowest levels. Age, smoking, gender, T CD4 lymphocytes levels and viral load did not influence subgingival LF levels, neither for SS nor for DP. Positive fungal culture was observed in 24 HIV-infected patients, but only observed in one in the control group. Overall, LF concentration was significantly higher in DS than SS, both in HIV-infected and noninfected individuals (P < 0.05) and salivary LF levels were always higher than GCF levels.

CONCLUSION

The data indicate that LF levels in the GCF and saliva are not different between HIV-infected and noninfected patients with chronic periodontitis.

Effect of mobile phone use on salivary concentrations of protein, amylase, lipase, immunoglobulin A, lysozyme, lactoferrin, peroxidase and C-reactive protein of the parotid gland

BACKGROUND

The possibility of side effects associated with the electromagnetic waves emitted from mobile phones is a controversial issue. The present study aimed to evaluate the effect of mobile phone use on parotid gland salivary concentrations of protein, amylase, lipase, immunoglobulin A, lysozyme, lactoferrin, peroxidase and C-reactive protein.

METHODS

Stimulated salivary samples were collected simultaneously from both parotid glands of 86 healthy volunteers. Salivary flow rate and salivary concentrations of proteins, amylase, lipase, lysozyme, lactoferrin, peroxidase, C-reactive protein and immunoglobulin A, were measured. Data were analysed using t-tests and one-way analyses of variance.

RESULTS

Salivary flow rate and parotid gland salivary concentrations of protein were significantly higher on the right side compared to the left in those that predominantly held mobile phones on the right side. In addition, there was a decrease in concentrations of amylase, lipase, lysozyme, lactoferrin and peroxidase.

CONCLUSION

The side of dominant mobile phone use was associated with differences in salivary flow rate and parotid gland salivary concentrations, in right-dominant users. Although mobile phone use influenced salivary composition, the relationship was not significant.

Adaptive HIV-specific B cell-derived humoral immune defenses of the intestinal mucosa in children exposed to HIV via breast-feeding

Background

We evaluated whether B cell-derived immune defenses of the gastro-intestinal tract are activated to produce HIV-specific antibodies in children continuously exposed to HIV via breast-feeding.

Methods

Couples of HIV-1-infected mothers (n = 14) and their breastfed non HIV-infected (n = 8) and HIV-infected (n = 6) babies, and healthy HIV-negative mothers and breastfed babies (n = 10) as controls, were prospectively included at the Complexe Pédiatrique of Bangui, Central African Republic. Immunoglobulins (IgA, IgG and IgM) and anti-gp160 antibodies from mother’s milk and stools of breastfed children were quantified by ELISA. Immunoaffinity purified anti-gp160 antibodies were characterized functionally regarding their capacity to reduce attachment and/or infection of R5- and X4- tropic HIV-1 strains on human colorectal epithelial HT29 cells line or monocyte-derived-macrophages (MDM).

Results

The levels of total IgA and IgG were increased in milk of HIV-infected mothers and stools of HIV-exposed children, indicating the activation of B cell-derived mucosal immunity. Breast milk samples as well as stool samples from HIV-negative and HIV-infected babies exposed to HIV by breast-feeding, contained high levels of HIV-specific antibodies, mainly IgG antibodies, less frequently IgA antibodies, and rarely IgM antibodies. Relative ratios of excretion by reference to lactoferrin calculated for HIV-specific IgA, IgG and IgM in stools of HIV-exposed children were largely superior to 1, indicating active production of HIV-specific antibodies by the intestinal mucosa. Antibodies to gp160 purified from pooled stools of HIV-exposed breastfed children inhibited the attachment of HIV-1NDK on HT29 cells by 63% and on MDM by 77%, and the attachment of HIV-1JRCSF on MDM by 40%; and the infection of MDM by HIV-1JRCSF by 93%.

Conclusions

The intestinal mucosa of children exposed to HIV by breast-feeding produces HIV-specific antibodies harbouring in vitro major functional properties against HIV. These observations lay the conceptual basis for the design of a prophylactic vaccine against HIV in exposed children.

Salivary IgA to cariogenic bacteria in HIV-positive children and its correlation with caries prevalence and levels of cariogenic microorganisms

The interrelationship of HIV infection, dental caries and mucosal immune responses remains controversial. In our study population of 40 HIV-infected and 40 healthy control children (ages 2-5 years) there was a significantly higher prevalence of dental caries in HIV-infected children (P<0.05). The extent of caries correlated with the severity of HIV disease. To determine whether the immunosuppression that ensues after HIV infection could contribute to the increased caries prevalence, the concentrations of total IgA and IgA specific to cariogenic bacteria (Streptococcus mutans, Streptococcus sobrinus and Lactobacillus acidophilus) were determined in whole saliva by enzyme-linked immunosorbent assay. Levels of the same bacteria were also quantified in saliva using checkerboard DNA-DNA hybridization. A significantly increased level of total salivary IgA was found in the HIV-positive population (P < 0.05), but there were comparable titers of specific IgA to cariogenic bacteria in HIV-positive and healthy controls. The microbiological assessment also demonstrated similar levels of cariogenic microorganisms in both groups. We conclude that HIV-positive children appear to maintain the capacity to mount a mucosal immune response to cariogenic microorganisms, at least until late stages of disease.