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Bacterial attachment to urinary-tract epithelium is important in the pathogenesis of urinary-tract infection. Most pyelonephritogenic Escherichia coli bind specifically to epithelial-cell receptors, which are glycolipids of the globoseries and also antigens in the P blood-group system. Among 36 girls with recurrent pyelonephritis who did not have vesicoureteral reflux, we found that attaching bacteria were common and the P1 blood-group phenotype was present in 97 per cent, as compared with 75 per cent of 84 age-matched children without urinary-tract infection (P less than 0.01). In 32 girls with recurrent pyelonephritis who had reflux, attaching bacteria were rare, and the frequency of the P1 phenotype was not significantly higher than in controls (82 per cent, P greater than 0.05). In the group of patients with the P1 phenotype, 68 per cent of the urinary bacterial isolates from those without reflux, but only 25 per cent of isolates from those with reflux, bound to globotetraosylceramide, as determined by a receptor-coating technique (P less than 0.001). Our data suggest that, in the absence of reflux, the P1 blood group contributes to susceptibility to recurrent pyelonephritis due to bacteria that bind to the glycolipid receptors of the globoseries. In the presence of reflux, uroepithelial attachment does not seem to confer an advantage to bacteria that infect the kidney.

A total of 124 children aged 0.2 to 6 years were enrolled in a study of first time febrile urinary tract infection. The patient population was stratified in groups according to the stringency of criteria for fever and bacteriuria and the presence of concomitant disease. The major group of 88 patients consisted of children with fever greater than or equal to 38.5 degrees C measured at the hospital within 24 hours of diagnosis, bacteriuria verified by suprapubic bladder aspiration or repeated cultures of voided urine, but without concomitant disease. These children were mainly infected with attaching Escherichia coli specific for galactose alpha (1----4) beta galactose containing receptors and had laboratory evidence of inflammation. Another group of 11 children were distinguished with strictly defined bacteriuria and concomitant disease. These children were infected with nonattaching bacteria and had lower concentrations of C-reactive protein in serum and lower microsedimentation rates than the major group. Five of these children had a reduction in renal concentrating capacity. The study emphasizes the heterogeneity among patients with fever and bacteriuria but does not rule out the possibility of renal involvement in any subgroup.

Mucins are high-molecular-weight glycoproteins and major constituents of the mucus layer which covers the airway surface. We have studied the interactions between bacteria, mucins, and epithelial cells from the human respiratory tract. Nontypeable strains of Haemophilus influenzae were found to bind to purified airway mucins in suspension and on solid phase. Mucins in suspension inhibited the attachment of these strains to nasopharyngeal epithelial cells, while mucin coating of the cells enhanced their binding. In contrast, strains of Streptococcus pneumoniae and encapsulated and other nontypeable H. influenzae strains failed to interact with mucins. These H. influenzae strains used other strategies for adherence to epithelial cells. The type b strain 770235 attached via fimbriae but also expressed a subcapsular adhesin that was detected in a capsule- and fimbria-defective mutant. Mucin pretreatment of these bacteria did not inhibit adherence, but mucin pretreatment of epithelial cells inhibited adherence, probably by shielding of the receptors for these adhesins. Non-mucin-binding nontypeable and encapsulated H. influenzae strains would, therefore, adhere only after disruption of the mucus layer and exposure of cellular receptors. Differences in tissue toxicity and invasiveness among H. influenzae strains may also be influenced by the mucin interactions of the strains.

New cancer treatments should aim to destroy tumor cells without disturbing normal tissue. HAMLET (human alpha-lactalbumin made lethal to tumor cells) offers a new molecular approach to solving this problem, because it induces apoptosis in tumor cells but leaves normal differentiated cells unaffected. After partial unfolding and binding to oleic acid, alpha-lactalbumin forms the HAMLET complex, which enters tumor cells and freezes their metabolic machinery. The cells proceed to fragment their DNA, and they disintegrate with apoptosis-like characteristics. HAMLET kills a wide range of malignant cells in vitro and maintains this activity in vivo in patients with skin papillomas. In addition, HAMLET has striking effects on human glioblastomas in a rat xenograft model. After convection-enhanced delivery, HAMLET diffuses throughout the brain, selectively killing tumor cells and controlling tumor progression without apparent tissue toxicity. HAMLET thus shows great promise as a new therapeutic with the advantage of selectivity for tumor cells and lack of toxicity.

All living cells, whether in unicellular or multicellular organisms, surround themselves with a shell of carbohydrates. In mammals, epithelial surfaces, which are primarily exposed to other organisms, are particularly rich in carbohydrates. The carbohydrates are characterized by great structural diversity and variability related to individual, species, and cell type. Therefore, carbohydrates are good candidates to be involved in interactions of self with non-self. Microorganisms frequently express carbohydrate binding proteins that may interact specifically with host glycoconjugates (1). Early studies showed that NeuAc, Man, and GM I gangliosides act as receptors for influenza virus, Escherichia coli fimbriae, and cholera toxin, respectively (1). Evidence is now accumulating for the presence of a wide variety of such proteins with many different specificities. Host cell-bacterial interactions can be studied at three levels. At the molecular level, the bacterial binding activities and their specificity are identified and the interacting molecules characterized, i.e., a glycoconjugate on the host and an adhesin or toxin on the bacterium. At the cellular level, binding activities on cultured cells or organ cultures are studied in vitro. At the physiologic level, the biomedical relevance of the binding activities is assessed in animal models and by epidemiologic studies. The article by Dal Nogare in this issue of the journal (2) falls primarily in the latter two categories. Here we will comment on all three approaches, with emphasis on the glycoconjugates of the host. Other mechanisms of host-pathogen interaction are being discovered, such as interaction of bacterial saccharides with host proteins (lectins), protein-protein interactions, hydrophobic interactions, immunologic cross-reactivity between host and microbial antigens, and various other adaptations to the host environment (e.g., 3). However, these are beyond the scope of the present review. The molecular level. In the now "classical" model of adhesion for gram-negative bacteria, thin appendages (fimbriae, pili) on the bacterial surface interact with glycoconjugates on the host cell surface (1, 4). Improved molecular genetic and biochemical techniques, greater availability of purified complex glycoconjugates, and improved binding assays have now

This study compared the repertoire of cytokines produced by epithelial cell lines and human peripheral blood monocytes in response to Escherichia coli. The A-498 and J82 urinary tract epithelial cell lines and human peripheral blood monocytes were exposed to E. coli Hu734. The cytokine content of single cells was detected by indirect immunofluorescence using monoclonal antibodies to interleukin-1 alpha (IL-1 alpha), IL-1 beta, tumor necrosis factor alpha (TNF-alpha), TNF-beta, IL-6, IL-8, and granulocyte macrophage-colony-stimulating factor, and the number of positive cells was used to quantitate the response. The J82 bladder cell line stained positive for IL-6, IL-8, and IL-1 alpha. The IL-8 and IL-6 response peaked at 2 h, while the number of IL-1 alpha-positive cells reached a peak 6 h after E. coli stimulation. The A-498 kidney cell line stained for IL-8 with a peak at 2 h and IL-6 with a peak at 6 h after E. coli stimulation. Peripheral blood monocytes stained for the cytokines IL-1 alpha, IL-1 beta, IL-8, IL-6, and TNF-alpha but not for TNF-beta and granulocyte macrophage-colony-stimulating factor after stimulation with E. coli. The results demonstrated that bacteria activated a cytokine response in the epithelial cell lines and monocytes. The epithelial cell lines had a more limited cytokine response profile than circulating monocytes, which may serve to limit the consequences of microbial exposure at the mucosal surface and help maintain the integrity of other tissue compartments.

Urine and serum interleukin (IL)-6 and IL-8 responses were higher in children with febrile urinary tract infection (n = 61) than in those with asymptomatic bacteriuria (n = 39). By univariate analysis, cytokine levels were related to age, sex, reflux, renal scarring, urine leukocytes, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and bacterial properties (P fimbriae but not hemolysin). Multivariate modeling showed that urine IL-6 responses were higher in girls than boys, increased with age, and were positively associated with CRP, ESR, serum IL-6, and urine leukocyte counts. The urine IL-8 response was not influenced by age, but it was influenced by P fimbriae and was associated with ESR, CRP, urine leukocytes, and female sex. The results show that cytokine responses to urinary tract infection vary with the severity of infection and that cytokine activation is influenced by a variety of host and bacterial variables.

The mechanism whereby attachment enhances Escherichia coli virulence in the urinary tract was studied by a detailed analysis of the host response to bacteriuria. Episodes of bacteriuria in 1473 children were followed prospectively from 1970 to 1984. To study the inflammatory response to the bacteriuric epidoses, we recorded body temperature, C-reactive protein, microsedimentation rate, urinary leukocyte count, and renal concentrating capacity. Bacterial isolates from each episode were identified and saved, and the adhesive capacity of 2669 E. coli strains was defined by their binding to galactose alpha 1----4galactose beta-containing receptors. Inflammatory response was significantly higher and renal concentrating capacity significantly lower during episodes caused by attaching strains. There was a linear relation between the number of indicators of inflammation and the proportion of galactose alpha 1----4galactose beta-binding strains present. Vesicoureteric reflux potentiated the inflammatory response. Attaching strains of E. coli thus appeared to be more capable of causing inflammation than were other bacteria. The potentiating effect of attachment on inflammation explains the over-representation of galactose alpha 1----4galactose beta-recognizing bacteria in patients with acute pyelonephritis.

HAMLET (human alpha-lactalbumin made lethal to tumor cells) is a tumoricidal complex consisting of partially unfolded protein and fatty acid and was first identified in casein fractions of human breast milk. The complex can be produced from its pure components through a modified chromatographic procedure where preapplied oleic acid binds with partially unfolded alpha-lactalbumin on the stationary phase in situ. Because native alpha-lactalbumin itself cannot trigger cell death, HAMLET's remarkable tumor-selective cytotoxicity has been strongly correlated with the conformational change of the protein upon forming the complex, but whether a recovery to the native state subsequently occurs upon entering the tumor cell is yet unclear. To this end, we utilize a recombinant variant of human alpha-lactalbumin in which all eight cysteine residues are substituted for alanines (rHLA(all-Ala)), rendering the protein nonnative and biologically inactive under all conditions. The HAMLET analogue formed from the complex of rHLA(all-Ala) and oleic acid (rHLA(all-Ala)-OA) exhibited equivalent strong tumoricidal activity against lymphoma and carcinoma cell lines and was shown to accumulate within the nuclei of tumor cells, thus reproducing the cellular trafficking pattern of HAMLET. In contrast, the fatty acid-free rHLA(all-Ala) protein associated with the tumor cell surface but was not internalized and lacked any cytotoxic activity. Structurally, whereas HAMLET exhibited some residual native character in terms of NMR chemical shift dispersion, rHLA(all-Ala)-OA showed significant differences to HAMLET and, in fact, was found to be devoid of any tertiary packing. The results identify alpha-lactalbumin as a protein with strikingly different functions in the native and partially unfolded states. We posit that partial unfolding offers another significant route of functional diversification for proteins within the cell.