ABSTRACT
The trophozoites of Giardia lamblia possess several protein antigens, predominant among them a protein of approximately 32,000 Da. In the present study, we used monospecific antibodies that recognize this protein to demonstrate its presence on a variety of G. lamblia isolates from human and animal sources. Immune electron microscopy was used to localize 32-kDa antigen on the trophozoite membrane and disk. Immunofluorescent assays employing monospecific antibodies confirmed the presence of 32-kDa antigen on the membrane and disk and its absence on flagella or nuclei. The N-terminal 17 amino acids of the 32-kDa antigen are identical to alpha-1-giardin, a protein component of microribbons on the ventral disk. These results suggest that the 32-kDa immunodominant trophozoite antigen is alpha-1-giardin.
Subject(s)
Antigens, Protozoan/isolation & purification , Cytoskeletal Proteins/isolation & purification , Giardia lamblia/immunology , Immunodominant Epitopes/isolation & purification , Protozoan Proteins/isolation & purification , Amino Acid Sequence , Animals , Antibodies, Protozoan , Antibody Specificity , Antigens, Protozoan/genetics , Antigens, Protozoan/immunology , Cell Movement , Cytoskeletal Proteins/genetics , Cytoskeletal Proteins/immunology , Fluorescent Antibody Technique , Giardia lamblia/ultrastructure , Glycosylation , Immunodominant Epitopes/genetics , Immunodominant Epitopes/immunology , Microscopy, Immunoelectron , Molecular Sequence Data , Protein Processing, Post-Translational/drug effects , Protozoan Proteins/genetics , Protozoan Proteins/immunology , Sequence Analysis , Tunicamycin/pharmacologyABSTRACT
OBJECTIVE: This study investigated the relationship between colonization and fungemia. DESIGN: This was a prospective study involving surveillance cultures of the nares, base of umbilicus, point of entry of umbilical catheter and parenteral fluids. Blood cultures were done when sepsis was suspected. All Candida albicans isolates were typed using restriction enzyme analysis of DNA. SETTING: Patients were from the neonatal intensive care unit of a tertiary care hospital. POPULATION STUDIED: Twenty-nine very low birthweight infants. MAIN RESULTS: Eleven babies were colonized with C albicans and five of these babies developed fungemia, including five of seven who were colonized at the point of entry of the umbilical catheter. Three different strains of C albicans caused fungemia. In four of the five patients, initial catheter entry site isolates were identical to the subsequent blood isolates. Occasionally, infants were colonized with more than one strain of C albicans. CONCLUSIONS: Preceding colonization with C albicans and, in particular, colonization at the site of entry of umbilical vascular catheters are risk factors for subsequent development of C albicans fungemia. Fungemic and colonizing isolates are usually identical to one another by DNA typing.
ABSTRACT
Giardia duodenalis is a common intestinal parasite in most parts of the world. In Canada it is associated with both endemic and epidemic infections that are often transmitted by the waterborne route. Although G. duodenalis strains have been isolated from several animals, the role of other mammals in human infection is unclear. We have isolated and cultured G. duodenalis trophozoites from domestic and wild animals in Alberta and compared them with a human isolate by protein gel electrophoresis and immunoblot analysis. All strains examined share a similar polypeptide profile and important protein antigens. Prominent antigens of 62, 52, 38, and 31 kilodaltons are conserved. The 52- and 31-kilodalton proteins are the major surface-exposed trophozoite components. The high degree of antigenic sharing among strains from different hosts suggests that there may be a wide range of potential reservoirs for G. duodenalis infections.
Subject(s)
Antigens, Protozoan/analysis , Giardia/immunology , Alberta , Animals , Arvicolinae , Autoradiography , Dogs , Electrophoresis, Polyacrylamide Gel , Giardia/isolation & purification , Humans , Immunologic Techniques , Rodentia , SheepABSTRACT
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 chlamydial adhesins play a key role in the early steps of chlamydia-host cell interaction and that antibody directed against them may be protective.
