Diarrhea in neonates, followed as a cohort, and their families was studied prospectively. The families were followed for an average of 16.3 months. Stool and serum specimens were obtained at least every three months. Stool specimens were examined for viruses by electron microscopy and cultured for enteropathogens, and serum specimens were tested for antibodies to rotavirus and Norwalk virus. During the study, 237 episodes of gastroenteritis were observed in 104 infants and their 62 siblings. Rotavirus, detected 82 times in 72 children, was by far the most common enteropathogen. It was associated with gastrointestinal symptoms in 72% (with diarrhea in 65%). Rotavirus diarrhea occurred mostly in winter months and was significantly more frequently associated with respiratory symptoms than were diarrheas with other etiologies. Rotavirus infection was uncommon in the first six months of life, but by two years of age, 62% of the infants had had at least one infection. Neither breast feeding nor the presence of antibody to rotavirus in cord blood appeared to be protective.

Chlamydia trachomatis proteins were electrophoresed and then transferred to nitrocellulose paper to detect chlamydial proteins which bind to eucaryotic cell membranes. Resolved polypeptides of C. trachomatis serovars J and L2 were reacted with iodinated HeLa cell membranes and autoradiographed. Infectious elementary bodies of both serovars possess 31,000-and 18,000-dalton proteins which bind to HeLa cells. In contrast, noninfectious reticulate bodies do not possess eucaryotic cell-binding proteins. Both proteins are antigenic when reacted with hyperimmune rabbit antisera in immunoblots and antisera raised against the 31,000-and 18,000-dalton proteins are inhibitory to chlamydia-host cell association. In addition, these antisera exhibit neutralizing activity. Our data suggest that these putative chiamydial adhesins play a key role in the early steps of chlamydia-host cell interaction and that antibody directed against them may be protective.Chlamydiae are obligate intracellular parasites which have been linked to an expanding spectrum of human disease (12,23). The infectious forms of the organism, elementary bodies (EB), attach to host cells and, once ingested, initiate a unique developmental cycle (24). The intracellular reticulate bodies (RB) are noninfectious, larger, and more fragile than EB and display differences in their protein profile (10).Although chlamydiae appear to be internalized by an endocytic-like process (3,25,27), neither a chlamydial adhesin nor a host cell receptor has yet been identified. Information that EB are ingested more efficiently than are Escherichia coli or latex spheres implicates a specific mechanism for chlamydial attachment and uptake (3). Although a chlamydial ligand has not been characterized, the finding that EB cell walls attach to and are ingested by host cells nearly as efficiently as are whole EB (18) implicates cell wall components as putative adhesins. Earlier information that attachment is inhibited by heating EB provides evidence that the adhesin is a protein (2, 3). However, heat inhibition was only partial and was not observed with a serovar A Chlamydia trachomatis strain (17). Antiserum to whole EB inhibits attachment (3), but antibody to the major outer membrane (OM) protein does not affect either attachment or uptake of EB (4). To elucidate the initial steps of association between chlamydiae and host cells the objective of the present study was the identification and preliminary characterization of adhesin(s). We utilized a procedure which allows the detection of separated bacterial polypeptides on nitrocellulose that bind to eucaryotic cell membranes to identify putative adhesins on the surface of C. trachomatis. MATERIALS AND METHODSGrowth and purification of chlamydiae. C. trachomatis serovars L2/434/Bu (L2) and J/UW-36 (J) were grown in HeLa 229 cells as described by Kuo et al. (15). Cultures were harvested at 48 h for EB or 18 h for RB, and cells were removed with sterile glass beads. The cell suspension was sonicated and submitted sequentially to differenti...

Our results demonstrate marginally significant prevalence of C pneumoniae DNA in patients with CAD compared with healthy subjects (P=0.082). In contrast, the prevalence of IgG seropositivity among the 2 groups did not reach statistical significance (P=0.306). We also provide unequivocal evidence for the presence of C pneumoniae DNA predominantly among the circulating CD3+ T-cell population.