Bacterial attachment to oropharyngeal epithelial cells in breastfed newborns

Placental transfer of maternally-derived IgA precludes the use of guthrie card eluates as a screening tool for primary immunodeficiency diseases

There is a need for neonatal screening tools to improve the long-term clinical outcome of patients with primary immunodeficiency diseases (PID). Recently, a PCR-based screening method for both TRECs and KRECs using Guthrie card samples has been developed. However, the applicability of these excision circle assays is limited to patients with severe T or B cell lymphopenia (SCID, XLA and A-T), whereas the most common forms of PID are not detected. Absence of serum IgA is seen in a major fraction of patients with immunological defects. As serum IgA in newborns is considered to be of fetal origin, eluates from routinely collected dried blood spot samples might thus be suitable for identification of children with PID. To assess the applicability of such screening assays, stored Guthrie card samples were obtained from 47 patients with various forms of primary immunodeficiency diseases (SCID, XLA, A-T, HIGM and IgAD), 20 individuals with normal serum IgA levels born to IgA-deficient mothers and 51 matched healthy newborns. Surprisingly, normal serum IgA levels were found in all SCID, XLA, A-T and HIGM patients and, additionally, in all those IgAD patients born to IgA-sufficient mothers. Conversely, no serum IgA was found in any of the 16 IgAD patients born by IgA-deficient mothers. Moreover, half of the IgA-sufficient individuals born by IgA-deficient mothers also lacked IgA at birth whereas no IgA-deficient individuals were found among the controls. IgA in neonatal dried blood samples thus appears to be of both maternal and fetal origin and precludes its use as a reliable marker for neonatal screening of primary immunodeficiency diseases.

The Use of Probiotics in Head and Neck Infections

Recurrent episodes of infections in the upper respiratory tract are very common. The pathogenesis behind these recurrences is still not well understood, but much attention has been paid to the adherence of the microorganisms to epithelial structures and to the protective function of the normal bacterial flora (bacterial interference). Thus, in vitro as well as in vivo studies have shown that both aerobic and anaerobic bacteria of the normal flora in the upper respiratory tract can hinder the growth of pathogens and the establishment of a renewed infection. Studies have shown that lack of interfering bacteria facilitates recurrence of these diseases. Recolonization with interfering alpha-streptococci has been performed successfully in acute streptococcal pharyngotonsillitis, as well as in acute otitis media. The number of recurrences has significantly been lowered in these diseases after recolonization with alpha-streptococci, which is the dominating normal bacteria in the upper respiratory tract. Several mechanisms have been proposed to be responsible for this interaction, such as competition of the adhering sites at the epithelial cells, production of hydrogen peroxide, competition for nutritients, and production of specific growth inhibiting factors such as bacteriocins. Other human components like lactoferrin are also important in the defense against microorganisms, and are important parts of the unspecific and specific immune system.

Intranasal immunization with lipoteichoic acid and cholera toxin evokes specific pharyngeal IgA and systemic IgG responses and inhibits streptococcal adherence to pharyngeal epithelial cells in mice

OBJECTIVE

Streptococcus (S.) pyogenes is common cause of acute tonsillitis. Lipoteichoic acid (LTA), which is a common constitute of the cell surface of most gram positive bacteria, is known to act as a substance of bacterial site for adherence to epithelium and antiserum to LTA is reported to inhibit bacterial attachment to epithelial cells in vitro. Cholera toxin subunit B (CT-B) is known to be a mucosal adjuvant. The purpose of this study is to investigate whether intranasal immunization with LTA and CT-B may be a possible candidate for vaccine formulation.

METHODS

Six-week-old male BALB/c mice were assigned to three experimental groups, mice immunized with LTA and CT-B, with LTA alone and with phosphate buffered saline (PBS) as a control. Immunizations were performed intranasally every 2 days for 2 weeks in every group. At the 21 days after immunization, sera, pharyngeal washings and pharyngeal epithelial cells were taken. The levels of serum IgG and pharyngeal IgA antibodies to LTA were measured by enzyme-linked immunosorbent assay (ELISA). The adherence rates of S. pyogenes pretreated by pharyngeal washings to pharyngeal epithelial cells from the mice were determined by in vitro adherence assay.

RESULTS

The serum anti-LTA IgG antibody levels of either mice immunized with LTA and CT-B or mice immunized with LTA alone were significantly higher than those of mice administered with PBS alone. The pharyngeal anti-LTA IgA antibody levels of the mice immunized with LTA and CT-B were significantly higher than those of either mice with LTA alone or mice with PBS alone. The streptococcal adherence rates to pharyngeal epithelial cells were significantly decreased by pretreatment with pharyngeal washings from the mice immunized with LTA and CT-B as compared with pretreatment with those from either mice with PBS or mice with LTA alone.

CONCLUSIONS

These data shows that intranasal immunization with LTA and CT-B evokes a good pharyngeal IgA response as well as systemic IgG response to LTA and inhibits streptococcal adherence to pharyngeal epithelial cells, suggesting that intranasal immunization with LTA and CT-B may be an effective approach to prevent streptococcal tonsillitis.