Brief report: fatal seronegative ehrlichiosis in a patient with HIV infection.
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AIDS-Related Opportunistic Infections↗
Biomedical subjects
B E Anderson
Publications and source records attributed to B E Anderson.
Receptor-ligand interactions between serum amyloid P component and model soluble immune complexes.
We report here that isolated human serum amyloid P (SAP) binds aggregates of human IgG (AAg), which are model soluble immune complexes. The binding interaction was specific with regard to AAg compared to monomeric IgG, saturable, of high affinity, and reversible. With SAP adsorbed to microtiter plate wells, protein binding assays of AAg preparations with m.w. values of 1.05 to 2.25 x 10(6) were performed. The assay results yielded binding isotherms and estimates of the dissociation constant values of SAP:AAg binding ranging between 0.60 and 1.9 nM. Using the same method, the dissociation constant of SAP binding of biotinylated AAg was estimated to be approximately 3.0 nM. Competitive protein binding assays using biotinylated AAg and unlabeled AAg or monomeric IgG were performed to determine the relative affinity (IC50) of SAP binding. The IC50 values ranged from 22 to 51 nM for different sizes of AAg. The IC50 determined for monomeric IgG was 10 microM, demonstrating a relative specificity of SAP binding for AAg. The binding interaction was reversible, the SAP:AAg complexes dissociating with a t1/2 of 125 min. AAg binding to solid phase-adsorbed SAP was not dependent upon the presence of several cations, including calcium, but was not supported by cuprous ion. The differential binding of AAg vs monomeric IgG reported here for SAP is similar to the other human immune complex binding proteins C1q, rheumatoid factor, and cellular Ig C-region receptors. These results indicate that SAP:AAg binding has the hallmarks of a receptor:ligand interaction and may have implications for the disposal of immune complexes in vivo.
Antigen-Antibody Complex↗
Blood group antigen expression on vaginal and buccal epithelial cells and mucus in secretor and nonsecretor women.
Blood group antigens on epithelial cells may influence bacterial adherence to mucosal surfaces. In the urinary tract the presence of these genetically determined carbohydrate structures may affect bacterial colonization of the vaginal mucosa and subsequent urinary tract infection. In previous studies the detection of ABH and Lewis antigen expression and distribution in tissues have made use of semiquantitative immunohistochemical staining techniques. To determine the pattern and intensity of blood group antigens on epithelial cells and in the mucus overlying them, we developed quantitative immunoassays that use monoclonal antibodies to detect changes in the expression and intensity of ABH and Lewis antigens on cells and in mucus. Vaginal and buccal cell specimens from 23 healthy women (15 secretors and 8 nonsecretors) with no history of urinary tract infections and known blood group types were analyzed for the expression of these antigenic determinants. The profile of ABH antigen expression was generally consistent with the ABO phenotype of the individual and appeared to be influenced by the secretor status; the levels of A, B and H determinants were higher for secretors than nonsecretors. Lewis antigens were detected on vaginal and buccal cells, and mucus. Le(a) and Le(x) antigen expression was greater on cells and mucus from nonsecretors, whereas the expression of Le(b) and Le(y) was greater on cells and mucus from secretors. Variability in antigen expression was observed among individuals with the same blood type and secretor status. The patterns of antigen expression were similar for the vaginal and buccal cell, and mucus samples of an individual but the amount of antigen generally differed for the various samples. These findings document the variation of blood group antigen expression on vaginal epithelial cells and mucus, which may have a significant role in susceptibility to urinary tract infections in women.
ABO Blood-Group System↗
Ehrlichia chaffeensis expresses an immunoreactive protein homologous to the Escherichia coli GroEL protein.
A clone expressing a 58-kDa protein reactive with human convalescent-phase serum was isolated from a recombinant library of Ehrlichia chaffeensis, the etiologic agent of human ehrlichiosis. Sequencing identified two open reading frames, one encoding a 10.3-kDa polypeptide consisting of 94 amino acids and another encoding a 58-kDa polypeptide consisting of 550 amino acids. The sequences of the 10.3- and 58-kDa polypeptides were homologous to those of the Escherichia coli GroES and GroEL heat shock proteins, respectively.
Amino Acid Sequence↗
Supplementation of growing cattle grazing warm-season grass with proteins of various ruminal degradabilities.
This study was conducted to determine in situ ruminal protein degradation and animal responses to ruminally degraded and escape protein supplementation of warm-season grass. Cattle grazed a mixed stand of primarily big bluestem (Andropogon gerardii Vitman) and switchgrass (Panicum virgatum L.) with some indiangrass (Sorghastrum nutans [L.] Nash) from the 1st wk of June to the 3rd wk of August. In 1987, 72 yearling steers (286 kg) were allotted randomly to three treatments: energy control (cornstarch-molasses mixture) or energy control plus .1 or .2 kg.animal-1.d-1 of escape protein. The total amount of a supplement fed per day was 1 kg. In 1988, 90 yearling heifers (240 kg) were allotted to five treatments: negative control (no supplement), energy control, energy control plus .14 kg.animal-1.d-1 of escape protein, energy control plus .18 kg.animal-1.d-1 of ruminally degraded protein, or .36 kg.animal-1.d-1 of protein supplied by a combination of the two protein sources. The total amount of a supplement fed per day was 1.7 kg. During 1987, the .2-kg level of escape protein produced the greatest gains (P < .10). In 1988, gains did not differ between the control and escape protein treatments. Ruminally degraded protein tended (P = .12) to increase gains (.09 kg/d) compared with the energy control. The combination treatment supported .13 kg/d more ADG (P < .10) than the negative and energy controls and the escape protein treatment. Ruminal ammonia concentrations in unsupplemented steers were low, with few values > 5 mg/dL. Based on in situ measurements, 42 to 54% of the forage protein escaped ruminal degradation.(ABSTRACT TRUNCATED AT 250 WORDS)
Animal Feed↗
Amblyomma americanum: a potential vector of human ehrlichiosis.
Polymerase chain reaction primers specific for Ehrlichia chaffeensis were used to amplify DNA from extracts of pooled ticks. Amplification was performed on extracts from 140 pools (1,579 total ticks) consisting of three tick genera collected from five states. The characteristic 389-basepair product was observed after amplification of extracts from seven different pools of adult Amblyomma americanum (117 pools, 1,462 ticks), but not from pools of nymphs. No specific product was observed after amplification of 20 pools (105 ticks) of Dermacentor variabilis and three pools of Ixodes scapularis (12 ticks). Ehrlichia chaffeensis was present in A. americanum at a minimum frequency of > or = 0.48%, suggesting that A. americanum may be a vector of human ehrlichiosis.
Animals↗
Ehrlichia ewingii sp. nov., the etiologic agent of canine granulocytic ehrlichiosis.
The 16S rRNA gene was amplified, cloned, and sequenced from the blood of two dogs that were experimentally infected with the etiologic agent of canine granulocytic ehrlichiosis. The 16S rRNA sequence was found to be unique when it was compared with the sequences of other members of the genus Ehrlichia. The most closely related species were Ehrlichia canis (98.0% related) and the human ehrlichiosis agent (Ehrlichia chaffeensis) (98.1% related); all other species in the genus were found to be phylogenetically much more distant. Our results, coupled with previous serologic data, provide conclusive evidence that the canine granulocytic ehrlichiosis agent is a new species of the genus Ehrlichia that is related to, but is distinct from, E. canis and all other members of the genus. We propose the name Ehrlichia ewingii sp. nov.; the Stillwater strain is the type strain.
Animals↗
Characterization of a novel Rochalimaea species, R. henselae sp. nov., isolated from blood of a febrile, human immunodeficiency virus-positive patient.
Isolation of a Rochalimaea-like organism from a febrile patient infected with human immunodeficiency virus was confirmed. Analysis of 16S rRNA gene sequences, together with polymerase chain reaction and restriction endonuclease length polymorphism analysis of a portion of the citrate synthase gene, demonstrated that the agent is closely related to members of the genus Rochalimaea and that the isolate is genotypically identical to the presumptive etiologic agent of bacillary angiomatosis. However, the same genotypic analyses readily differentiated the new isolate from isolates of other recognized Rochalimaea species as well as other genera of bacteria previously suggested as putative etiologic agents of bacillary angiomatosis and related syndromes. We propose that the novel species be referred to as Rochalimaea henselae sp. now.
Adult↗
Detection of the etiologic agent of human ehrlichiosis by polymerase chain reaction.
Polymerase chain reaction (PCR) primers derived from a variable region of the 16S rRNA gene sequence were used to amplify DNA specifically from Ehrlichia chaffeensis (the recently proposed name for the etiologic agent of human ehrlichiosis). The 389-bp product defined by the specific primers was not detected when DNA samples from any of the other recognized species of Ehrlichia were used as amplification templates. When the PCR was applied to five suitable blood specimens obtained from patients subsequently shown to be serologically positive for E. chaffeensis, all five were positive. The same technique was applied to a total of six control blood specimens, three from febrile patients who had no serologic evidence of infection with Ehrlichia or Rickettsia species and three from patients diagnosed with Rocky Mountain spotted fever, and all six were negative. A chemiluminescent, group-specific oligonucleotide probe was shown to hybridize only with the PCR products obtained upon amplification of the five blood specimens from patients serologically diagnosed as having human ehrlichiosis. The results indicate that PCR, coupled with a nonisotopic method of confirming the identity of the PCR product, is a highly specific and efficient method of detecting the agent of human ehrlichiosis in blood. The results also suggest that E. chaffeensis is the sole etiologic agent of human ehrlichiosis in the United States. The technique was also applied to four ticks that were positive by direct immunofluorescence for Ehrlichia species, and one tick was PCR positive, indicating that E. chaffeensis DNA can be detected in ticks harboring this organism, although the sensitivity may be low.
Animals↗
Identification of Ehrlichia chaffeensis morulae in cerebrospinal fluid mononuclear cells.
We report a case of ehrlichiosis in a 72-year-old man who developed extreme lethargy, acute renal failure requiring hemodialysis, and respiratory insufficiency requiring intubation. Lumbar puncture performed on the second day of hospitalization revealed significant cellular pleocytosis. Ehrlichia morulae were tentatively identified in mononuclear cells in routinely processed Wright-stained cytospin preparations of cerebrospinal fluid (CSF). Identification was confirmed by a specific immunocytochemical staining procedure. Subsequent identification specifically as Ehrlichia chaffeensis morulae was established by polymerase chain reaction analysis, which revealed E. chaffeensis-specific DNA in CSF, bone marrow, and blood samples; by indirect fluorescent-antibody analysis, the patient developed an antibody titer of 32,768 against E. chaffeensis antigen. The patient responded to intravenous therapy with doxycycline and dexamethasone. Subsequently, neurologic, hematologic, renal, and pulmonary status had returned to baseline at follow-up 12 weeks after admission. To our knowledge, this is the first identification of E. chaffeensis morulae in CSF cells in an infected patient.
Aged↗
A biotin-streptavidin enzyme immunoassay for detection of antibodies to porcine granulosa cell antigens.
A colorimetric solid-phase enzyme immunoassay has been developed which quantifies antibodies to porcine granulosa cell membrane antigens in rabbits immunized with porcine granulosa cells. A cell-free, particulate membrane preparation of porcine granulosa cells was used as coating antigen. A biotinylated second antibody in conjunction with a streptavidin-beta-galactosidase conjugate was utilized to amplify reactivity. The enzyme beta-galactosidase was used due to high background obtained using peroxidase, presumably due to endogenous peroxidase activity of the tissue. Sigmoidal serum dilution curves were obtained with immune rabbit sera indicating that absorbance was related to the concentration of antibodies. Assay activity was reduced by preincubation of immune serum with granulosa cell membranes. Sera from ovariectomized or pre-immune rabbits did not yield any specific binding in the assay. This assay has potential applicability for quantifying antiovarian and antigranulosa cell antibodies in women suspected of having autoimmune premature ovarian failure.
Animals↗
A method for identifying a proposed carbohydrate-binding motif of proteins.
An examination of the binding sites of four carbohydrate binding proteins (Escherichia coli lactose repressor, E. coli arabinose-binding protein, yeast hexokinase A and Concanavalin A) revealed certain similarities of amino acid sequences and residues forming hydrogen bonds and hydrophobic interactions with the bound carbohydrate. These were: (i) Asx-Asx, hydrogen bonding to the pyranose ring oxygen and anomeric-OH group; (ii) Arg-X-X-X-(Ser/Thr), or the reverse sequence, with the Arg hydrogen bonding to the pyranose ring oxygen; (iii) Lys-(Ser/Thr)-X-X-Asp, or the reverse sequence and with interchange of the Lys-(Ser/Thr) positions, with hydrogen bonding of either or both the Lys and Asp residues to the -OH groups at carbons 2, 3, 4 or 6; (iv) a diaromatic sequence with possible hydrophobic interactions to the faces of the pyranose ring structure. An algorithm was devised to search the amino acid sequences of a large number of proteins, those known to bind carbohydrates as well as those without known carbohydrate-binding activities, for the four amino acid sequence criteria. The algorithm incorporated a weighted distance value (WDV) to assess the approximate distance between any two criteria, with the WDV being based on the predicted secondary structure of the protein amino acid sequence. When the algorithm using criteria 1 and 2 plus the WDV was applied to the sequences of 125 proteins, the method indicated the presence of the potential carbohydrate-binding site motif for 42% of proteins with known carbohydrate binding, only 8% of proteins were predicted as false positives, and the accuracy of the method was calculated to be 61.6%.(ABSTRACT TRUNCATED AT 250 WORDS)
Algorithms↗
Isolation and characterization of an Ehrlichia sp. from a patient diagnosed with human ehrlichiosis.
A new disease was recognized in the United States in 1986. The etiologic agent, although not previously isolated from a human, appeared to be serologically related to Ehrlichia canis, a canine leukotropic rickettsia. We obtained blood specimens from 27 febrile patients with a history of tick exposure. Leukocytes from 24 patients not treated with tetracycline were placed onto a monolayer of DH82 cells. We performed indirect immunofluorescence on sera from all 27 febrile patients as well as sera from 12 patients with previously diagnosed ehrlichiosis. Intractoplasmic inclusions were first observed in culture 35 days after the addition of infected blood from one patient. Partial sequencing of the rRNAs from the human isolate and E. canis indicated that they are 98.7% related. Positive indirect immunofluorescence reactions to the human isolate were obtained for all 12 previously diagnosed patients and for 33% of the 27 febrile patients. Two patients were seropositive for the human isolate but not for E. canis. No sera were positive for E. canis and negative for the human isolate. We report the isolation of a previously unrecognized Ehrlichia sp. that appears to be the etiologic agent of human ehrlichiosis. Serologic data (range of antibody titers, 256 to 32,768) in combination with rRNA sequencing indicated that the newly isolated Ehrlichia sp. is similar, but not identical, to E. canis.
Adult↗
Ehrlichia chaffeensis, a new species associated with human ehrlichiosis.
The bacterial 16S rRNA genes from blood samples of two patients with human ehrlichiosis and from an isolate recovered from one of the patients were amplified by using the polymerase chain reaction. The amplimers were then cloned and sequenced. The 16S rRNA gene sequence was also determined for Ehrlichia canis (two strains), E. equi, E. phagocytophila (two strains), and E. sennetsu (two strains). These sequences, along with a previously published 16S rRNA gene sequence of E. risticii, were compared. The 16S rRNA gene sequences were identical for all three sources of the human ehrlichiosis agent. The sequence comparisons indicate that the human ehrlichiosis agent is a new species most closely related to E. canis (98.2%) and more distantly related to other Ehrlichia spp. We propose that this species be named Ehrlichia chaffeensis sp. nov., with the Arkansas strain as the type strain.
Base Sequence↗
Nucleotide sequence of the P34 gene from Rickettsia rickettsii.
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Amino Acid Sequence↗
An immune complex selective affinity matrix utilizing a synthetic peptide.
A synthetic peptide possessing an amino acid sequence patterned on the globular head region of human complement component 1 subcomponent q (C1q) was tested for immunoglobulin binding. The peptide designated complementary binding peptide 2 (CBP2) was able to inhibit Staphylococcus aureus Protein A and human C1q from binding rabbit immunoglobulin at peptide concentrations for 50% inhibition of 1 and 10 microM, respectively. When attached to a solid-phase matrix in a column, CBP2 was able to bind immune complexes consisting of horseradish peroxidase plus rabbit antiperoxidase antibody or alkali-aggregated human immunoglobulins. A 1:4 mixture of immune complex to free immunoglobulin when passed over the CBP2 column demonstrated selective immune complex binding. Further controls established that CBP2 was in fact binding the immunoglobulin component of the immune complexes in a reversible fashion. The immune complex specificity of the column suggested a functional affinity was forming when CBP2 interacted with immune complexes. The possibility that the sequence of CBP2 is part of the immunoglobulin binding site of human C1q is discussed.
Amino Acid Sequence↗
A possible receptor-binding function for the N-terminus of connective tissue activating peptide III.
Connective tissue activating peptide III (CTAP-III) is an 85-residue peptide which has been purified from platelets and shown to possess mitogenic activity toward a variety of fibroblastic cell lines. beta-Thromboglobulin (beta TG) is an 81-residue peptide which is derived from CTAP-III by cleavage of the N-terminal tetrapeptide Asn-Leu-Ala-Lys which results in the loss of mitogenic activity. The near-UV CD spectra for the two proteins indicated that the conformations as well as the electronic environments of the two disulfide bonds, and also of the single aromatic tyrosine residue, were similar in CTAP-III and beta TG. However, differences in the far-UV CD spectra of these proteins indicated a substantial decrease in alpha-helical content for beta TG (29%) as compared to CTAP-III (38%). Structure prediction analysis also suggested that the longer N-terminal segment of CTAP-III may form an alpha-helix. The N-terminal region of beta TG, which lacks this tetrapeptide, was predicted to be in an unordered, or possibly a turn, conformation. This predicted structural difference appears to be due to the high helix-forming potential of the N-terminal tetrapeptide Asn-Leu-Ala-Lys in CTAP-III. These results suggest a possible structural role for the N-terminal region of CTAP-III in the expression of the biologic activities of this protein. On the basis of these studies, a reasonable hypothesis to account for the difference in mitogenic activity between beta TG and CTAP-III is that the N-terminal region must be helical for receptor binding to occur.
Amino Acid Sequence↗
Ventral arc of the os pubis: anatomical and developmental considerations.
The ventral arc is a ridge of bone which may occur on the ventral surface of the corpus of the os pubis in adult females. Recently, this feature of the human public bone has regained attention as being of value in ascribing sex. The ventral arc should not be confused with a somewhat similar crest that can occur in adult males, which is characterized by a different position and configuration than that of the ventral arc. The corpus is the site of both muscular and ligamentous attachments. The tissues correlated with adult bony morphology and its development in females and males during growth are described. The primary research question addresses the factors involved in the determination of bony differences between the sexes. Sexual dimorphism in bony features of the ventral aspect of the human os pubis relates to muscular origin and to differential growth patterns between males and females.
Adolescent↗