Adhesion and invasion of Streptococcus pneumoniae to primary and secondary respiratory epithelial cells.

The interaction between Streptococcus pneumoniae (S. pneumoniae) and the mucosal epithelial cells of its host is a prerequisite for pneumococcal disease development, yet the specificity of this interaction between different respiratory cells is not fully understood. In the present study, three areas were examined: i) The capability of the encapsulated S. pneumoniae serotype 3 strain (WU2) to adhere to and invade primary nasal­derived epithelial cells in comparison to primary oral­derived epithelial cells, A549 adenocarcinoma cells and BEAS­2B viral transformed bronchial cells; ii) the capability of the unencapsulated 3.8DW strain (a WU2 derivative) to adhere to and invade the same cells over time; and iii) the ability of various genetically­unrelated encapsulated and unencapsulated S. pneumoniae strains to adhere to and invade A549 lung epithelial cells. The results of the present study demonstrated that the encapsulated WU2 strain adhesion to and invasion of primary nasal epithelial cells was greatest, followed by BEAS­2B, A549 and primary oral epithelial cells. By contrast, the unencapsulated 3.8­DW strain invaded oral epithelial cells significantly more efficiently when compared to the nasal epithelial cells. In addition, unencapsulated S. pneumoniae strains adhered to and invaded the A459 cells significantly more efficiently than the encapsulated strains; this is consistent with previously published data. In conclusion, the findings presented in the current study indicated that the adhesion and invasion of the WU2 strain to primary nasal epithelial cells was more efficient compared with the other cultured respiratory epithelial cells tested, which corresponds to the natural course of S. pneumoniae infection and disease development. The target cell preference of unencapsulated strains was different from that of the encapsulated strains, which may be due to the exposure of cell wall proteins.

Streptococcus pneumoniae Cell-Wall-Localized Phosphoenolpyruvate Protein Phosphotransferase Can Function as an Adhesin: Identification of Its Host Target Molecules and Evaluation of Its Potential as a Vaccine.

In Streptococcus pneumonia, phosphoenolpyruvate protein phosphotransferase (PtsA) is an intracellular protein of the monosaccharide phosphotransferase systems. Biochemical and immunostaining methods were applied to show that PtsA also localizes to the bacterial cell-wall. Thus, it was suspected that PtsA has functions other than its main cytoplasmic enzymatic role. Indeed, recombinant PtsA and anti-rPtsA antiserum were shown to inhibit adhesion of S. pneumoniae to cultured human lung adenocarcinoma A549 cells. Screening of a combinatorial peptide library expressed in a filamentous phage with rPtsA identified epitopes that were capable of inhibiting S. pneumoniae adhesion to A549 cells. The insert peptides in the phages were sequenced, and homologous sequences were found in human BMPER, multimerin1, protocadherin19, integrinß4, epsin1 and collagen type VIIα1 proteins, all of which can be found in A549 cells except the latter. Six peptides, synthesized according to the homologous sequences in the human proteins, specifically bound rPtsA in the micromolar range and significantly inhibited pneumococcal adhesion in vitro to lung- and tracheal-derived cell lines. In addition, the tested peptides inhibited lung colonization after intranasal inoculation of mice with S. pneumoniae. Immunization with rPtsA protected the mice against a sublethal intranasal and a lethal intravenous pneumococcal challenge. In addition, mouse anti rPtsA antiserum reduced bacterial virulence in the intravenous inoculation mouse model. These findings showed that the surface-localized PtsA functions as an adhesin, PtsA binding peptides derived from its putative target molecules can be considered for future development of therapeutics, and rPtsA should be regarded as a candidate for vaccine development.

High-fiber diet promotes weight loss and affects maternal behavior in vervet monkeys.

The dramatic increase in obesity in western societies has shifted the emphasis in nutrition research from the problems of undernutrition to the adverse consequences of being overweight. As with humans, Old World monkeys are at increased risk for type II diabetes and other chronic diseases when they gain excessive weight. To prevent overweight and obesity, promote animal health, and provide a more natural level of fiber in the diet, the standard commercial monkey chow diet at a vervet monkey breeding colony was changed to a higher fiber formulation in 2004. The new diet was also higher in protein and lower in carbohydrate and energy density than the standard diet. Because maternal behavior is known to be sensitive to differences in resource availability, data on weight and mother-infant interactions for 147 mothers with 279 infants born from 2000 through 2006 were assessed for effects of the diet change. The results showed that, even though food was provided ad libitum, the mean body weight of breeding females was 10% lower after the transition to the high-fiber diet. Behaviorally, mothers on the high-fiber diet were significantly more rejecting to their infants, and their infants had to play a greater role in maintaining ventral contact in the first few months of their lives. The effects of the diet change on maternal rejection were significantly related to the mother's body weight, with lower-weight mothers scoring higher in maternal rejection. These results demonstrate that maternal behavior is responsive to changes in maternal condition, and that beneficial changes in the diet may have unintended consequences on behavior.

Flamingo cadherin: a putative host receptor for Streptococcus pneumoniae.

Streptococcus pneumoniae fructose bisphosphate aldolase (FBA) is a cell wall-localized lectin. We demonstrate that recombinant (r) FBA and anti-rFBA antibodies inhibit encapsulated and unencapsulated S. pneumoniae serotype 3 adherence to A549 type II lung carcinoma epithelial cells. A random combinatorial peptide library expressed by filamentous phage was screened with rFBA. Eleven of 30 rFBA-binding phages inhibited 90% of S. pneumoniae adhesion to A549 cells. The insert peptide sequence of 9 of these phages matched the Flamingo cadherin receptor (FCR) when aligned against the human genome. A peptide comprising a putative FBA-binding region of FCR (FCRP) inhibited 2 genetically and capsularly unrelated pairs of encapsulated and unencapsulated S. pneumoniae strains from binding to A549 cells. Moreover, FCRP inhibited S. pneumoniae nasopharyngeal and lung colonization and, possibly, pneumonia development in the mouse intranasal inoculation model system. These data indicate that FBA is an S. pneumoniae adhesin and that FCR is its host receptor.

Adolescent impulsivity predicts adult dominance attainment in male vervet monkeys.

Adolescence is characterized by behavioral and physiological changes that prepare individuals for the transition to adulthood. The purpose of this study was to evaluate the effects of behavioral, morphological, neurobiological, and developmental characteristics of adolescent male vervets in predicting later dominance attainment. Thirty-six adolescent male vervets were tested for social impulsivity by means of the Intruder Challenge test while they were still living in their natal groups. Body weight and cerebrospinal fluid (CSF) metabolites of serotonin, dopamine, and norepinephrine were measured before they were introduced into new matrilineal breeding groups at age 5. Stable adult dominance rank was determined at age 6, 1 year following introduction. The results indicated that body weight, adolescent impulsivity, and levels of 5-hydroxyindoleacetic acid (5-HIAA) and homovanillic acid (HVA) in CSF predicted adult dominance attainment. As expected, males that were above average in body weight prior to introduction were significantly more likely to become dominant. Males that were high in impulsivity as adolescents, and low in 5-HIAA prior to introduction were more likely to achieve stable alpha male status 1 year following introduction. The combination of these three factors resulted in correct prediction of rank attainment for 92% (33/36) of the males. Two other factors-maternal dominance rank and a measure of social anxiety from the Intruder Challenge test-were not related to adult dominance attainment in this sample. These results support the idea that there are benefits of a high-risk, high-gain strategy is beneficial for adolescent and young adult male vervets. They also demonstrate that adolescent impulsivity is age-limited. Males that achieved high rank moderated their behavior as adults, and no longer scored high in impulsivity relative to their age peers.