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Biomedical subjects

B L Rogers

Publications and source records attributed to B L Rogers.

At least 19 recordsLinked to original sources
PubMed1995

T cell epitope mapping of ragweed pollen allergen Ambrosia artemisiifolia (Amb a 5) and Ambrosia trifida (Amb t 5) and the role of free sulfhydryl groups in T cell recognition.

Ambrosia artemisiifolia (Amb a 5; Ra5S) and Ambrosia trifida (Amb t 5; Ra5G) are homologous allergens purified from short and giant ragweed pollen, respectively. Allergic human sera and hyperimmunized animal antisera directed against Amb a 5 or Amb t 5 show a high degree of species specificity, with little or no cross-reactivity between these two allergens, suggesting that the major Ab binding epitopes of Amb a 5 and Amb t 5 are distinct. Overlapping synthetic peptides derived from the allergen sequences were used to investigate the specificity of T cell responses in four strains of mice, BALB/c (H-2d), CBA (H-2k), C57BL/6 (H-2b), and A/J (H-2a). All four strains of mice responded to purified Amb a 5 and Amb t 5. Cross-reactivity was found at the T cell level between Amb a 5 and Amb t 5 in T cells from BALB/c, A/J, and CBA mice, but not in T cells from C57BL/6 mice. A T cell epitope from Amb a 5, residues 27-36 (PWQVVCYESS), was mapped using T cell hybridomas from BALB/c mice. A T cell epitope in Amb t 5 was mapped in the same strain to residues 24-34 (KYCVCYDSKAI). Disulfide bonds in Amb a 5 and Amb t 5 were found to be involved in T cell reactivity. Conversion of disulfide bridges into free sulfhydryl (SH) forms was required for the response of T cell hybridomas to peptide t5 (residues 27-40) from Amb t 5. Reduction of peptide a4 (residues 21-37) from Amb a 5 was essential for inducing the cross-reactivity observed with Amb t 5-specific T cell hybridomas. It is concluded that free sulfhydryl groups play a major role in the T cell recognition of cross-reactivity T cell epitopes within these related allergens.

Allergens↗
PubMed1995

IgE antibodies to recombinant forms of Fel d I: dichotomy between fluid-phase and solid-phase binding studies.

BACKGROUND: The major cat allergen Fel d I consists of two polypeptide chains linked by disulfide bonds, each of which has been expressed in bacteria. To investigate the antigenic structure of Fel d I, antibody binding to the native molecule and to each recombinant chain were compared. METHODS: Polyclonal human IgE and IgG antibodies and monoclonal antibodies (mAbs) to Fel d I were compared for binding to Fel d I, chain 1, or chain 2 by fluid-phase inhibition radioimmunoassay, RAST, and immunoabsorption. RESULTS: In the fluid-phase assay, neither recombinant chain significantly inhibited the binding of antibody to native Fel d I at concentrations of up to 10 micrograms/ml. Partial inhibition was observed when chain 1 was used, which inhibited the binding of two mAbs by 40% and 75%. In contrast, when the solid-phase RAST assay was used, IgE antibodies bound both chains with high specificity, and there was a good quantitative correlation between IgE antibody binding to Fel d I and both chain 1 (r = 0.58, p < 0.01) and chain 2 (r = 0.47, p < 0.01). Up to 70% of IgG or IgE anti-Fel d I antibodies could be absorbed by either chain 1 or chain 2, and both chains in combination produced similar absorption values in response to native Fel d I. Four mAbs were fully absorbed by chain 1, but not chain 2, and three mAbs were not absorbed by either chain. CONCLUSIONS: The results demonstrate a dichotomy between antibody binding to recombinant Fel d I chains, which may be explained by confirmational differences between the chains in the fluid phase or on solid supports. The results also suggest that chain 1 is an important site for mAb-defined B-cell epitopes on Fel d I.

Glycoproteins↗
PubMed1995

Differences between specificities of IgE and IgG4 antibodies: studies using recombinant chain 1 and chain 2 of the major cat allergen Felis domesticus (Fel d) I.

IgE- and IgG4 antibodies were compared for reactivity with recombinant chain 1 and chain 2 of the cat allergen Felis domesticus (Fel d) I. Recombinant chain 1 and chain 2 were coupled to sepharose and tested in IgE- and IgG4 radioallergosorbent test (RAST) experiments. Substantial IgE- and IgG4 binding was found. The fraction of Fel d I-specific antibody that bound to the recombinant chains was calculated. For chain 1, the mean value of this fraction was 0.30 for IgE and 0.23 for IgG4 (P = 0.05). For chain 2, the mean value of this fraction was 0.19 for IgE and 0.13 for IgG4 (P = 0.02). These results indicate that differences in fine specificity exist between IgE and IgG4 antibodies. Moreover, these findings support our results with chemically prepared peptides derived from these two chains and suggest that the B cells producing IgE antibodies are more likely to recognize a less 'native' form of Fel d I, compared with IgG4.

Adolescent↗
PubMed1994

Potential therapeutic recombinant proteins comprised of peptides containing recombined T cell epitopes.

The complete primary structure of Fel d I2 has been determined and shown to be comprised of two separate polypeptide chains (designated chain 1 and 2). Overlapping peptides covering the entire sequence of both chains of Fel d I have been used to map the major areas of human T cell reactivity. The present study describes three non-contiguous T cell reactive regions of < 30 aa in length that were assembled in all six possible configurations using PCR and recombinant DNA methods. These six recombinant proteins comprised of defined non-contiguous T cell epitope regions artificially combined into single polypeptide chains have been expressed in E. coli, highly purified, and examined for their ability to bind to human cat-allergic IgE and for human T cell reactivity. Several of these recombined T cell epitope-containing polypeptides exhibit markedly reduced IgE binding as compared to the native Fel d I. Importantly, the human T cell reactivity to individual T cell epitope-containing regions is maintained even though each was placed in an unnatural position as compared to the native molecule. In addition, T cell responses to potential junctional epitopes were not detected. It was also demonstrated in mice that s.c. injection of T cell epitope-containing polypeptides inhibits the T cell response to the individual peptides upon subsequent challenge in vitro. Thus, these recombined T cell epitope-containing polypeptides, which harbor multiple T cell reactive regions but have significantly reduced reactivity with allergic human IgE, constitute a novel potential approach for desensitization to important allergens.

Allergens↗
PubMed1994

Cloning and sequencing of the Dermatophagoides pteronyssinus group III allergen, Der p III.

House dust mites are widely recognized as major factors involved in the triggering of allergic diseases such as asthma. It is now apparent that the group III allergens of the Dermatophagoides mite species may play a significant role in a number of house dust mite allergic cases. Natural Der p III was isolated by gel filtration of salt precipitated Dermatophagoides pteronyssinus extract and as reported previously ran as a doublet of Mr 28 and 30 K on sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Natural Der fIII was isolated by affinity purification with the 5A12 monoclonal antibody. Amino acid sequence data was generated for both these proteins which was used to construct DNA probes to screen a Dermatophagoides pteronyssinus cDNA library by hybridization and resulted in the isolation of a recombinant Der p III cDNA clone, P3WS1. The 1059 bp cDNA fragment included a 786 bp open reading frame which encodes a pre-pro region of 29 amino acids and a mature protein of 232 amino acids with a calculated Mr 24,985. A search of the BLAST protein database has confirmed that the Der pIII P3WS1 clone is approximately 50% homologous with other trypsin proteins. We have confirmed with both our natural protein sequence and the P3WS1 amino acid sequence data that the group III allergens are trypsin-like proteins.

Allergens↗
PubMed1993

Sequence of the proteinase-inhibitor cystatin homologue from the pollen of Ambrosia artemisiifolia (short ragweed).

The nucleotide sequence of a cDNA (designated IPC1/5) encoding a cystatin (Cyt) proteinase-inhibitor homologue from short ragweed (Ambrosia artemisiifolia) pollen was determined and compared to other plant and animal Cyt. The absence of disulfide bonds in the predicted translation product of the IPC1/5 sequence suggests that it most resembles family-I members of the Cyt superfamily. Significant amino acid (aa) sequence identity was found when comparing the translated sequence of IPC1/5 to rice seed Cyt, human keratocyte Cyt A and human liver Cyt B.

Allergens↗
PubMed1993

Native and recombinant Fel dI as probes into the relationship of allergen structure to human IgE immunoreactivity.

To delineate the relationship between the structural conformation and the stability of an allergen and its antigenicity, we have chosen the major allergen from cat dander, Fel dI. From protein sequence analysis data we have examined the structure of the naturally occurring Fel dI and we have found it to exist as an anti-parallel heterodimer. We have used ELISA, RAST, Western blot and histamine release techniques to compare the IgE reactivity of a set of cat allergic patient samples to purified, native Fel dI and the E. coli expressed chains 1 and 2. Results from these studies demonstrate a significant level of IgE reactivity to all forms when examined for direct binding. However, both blot and ELISA competition assays show a much higher reactivity to Fel dI in solution compared to the separate recombinant chains and this is supported by the histamine release data. Although native Fel dI chain 2 contains an N-linked carbohydrate moiety, this does not seem to play a role in the reactivity of IgE to chain 2. Denaturation of Fel dI with alkali conditions leads to a dramatic decrease in IgE reactivity, even though measurable changes to the backbone structure of the protein are minimal. One proposed explanation is that both chains possess a core region determined by their primary structures and that the major IgE epitopes are dependent upon them. The relative reactivity amongst these allergen forms varied with the method of analysis, implying that the conformational requirements for IgE antibody binding are best studied by the application of more than one experimental protocol. Results from these qualitative analyses afford insight into the allergenicity of this exceptionally stable cat pelt protein.

Allergens↗
PubMed1992

Expression and genomic structure of the genes encoding FdI, the major allergen from the domestic cat.

The genes encoding chain 1 (Ch1) and chain 2 (Ch2) of the major allergen of the domestic cat, Felis domesticus I, have been analyzed by genomic cloning and by polymerase chain reaction (PCR). Ch1 has two potential leader sequences, designated A and B. Analysis of a genomic clone encoding Ch1 demonstrated that one structural gene contains sequences corresponding to both leaders, which utilize different Met start codons. PCR analysis showed that genes encoding Ch1 and Ch2 are co-expressed in both the salivary glands and the skin, and that leader sequence A of Ch1 is utilized preferentially in both tissues. Ch2 was shown to have two dominant forms that are differentially expressed in the aforementioned tissues. The long form (Ch2L), composed of 92 amino acids (aa), is preferentially expressed in the salivary glands, while the short form (Ch2S), composed of 90 aa, is preferentially expressed in the skin. There is minor sequence polymorphism in both forms of Ch2. A genomic clone for Ch2 only contained sequences for Ch2S, suggesting that Ch2L is encoded by an exon not contained within this genomic clone.

Allergens↗
PubMed1992

Evaluation of the impact of weaning food messages on infant feeding practices and child growth in rural Bangladesh.

In rural Bangladesh, a community-based weaning intervention used volunteers to teach complementary feeding to families of 62 breast-fed infants aged 6-12 mo. Over 5 mo, treatment children gained on average 0.46 SD (approximately 460 g) more in weight-for-age (WAZ) than the 55 control subjects, and were approximately 0.5 kg heavier at the final measure. The differences were statistically significant (P < 0.001). The percent median weight-for-age (WAPM) of treatment children held steady at 76% of the National Center for Health Statistics' reference, whereas the WAPM of control subjects dropped from 78% to 72%. The increase in percentage points of severe malnutrition (below -3 WAZ) was only 5% in the treatment group compared with 26% in the control subjects. Treatment children consumed a significantly greater percent of their energy and protein requirements from complementary foods than did control subjects. The affordable complementary foods consisted mainly of cereal porridge with oil and brown sugar. These findings suggest that educational interventions teaching families to feed hygienic, simple, cheap, energy-enriched complementary foods to breast-fed infants after 5-6 mo can improve child growth, even under impoverished conditions.

Bangladesh↗
PubMed1992

Project director characteristics in the Elderly Nutrition Program.

The federally funded Elderly Nutrition Program (ENP) began in 1972, authorized under Title 7 of the Older Americans Act. Its purpose was to serve elders, targeting those in greatest social and economic need. This article describes the characteristics of the Nutrition Project Directors in the ENP through data gathered by a questionnaire completed by a random sample of 430 directors across the nation. One important finding was that directors of programs serving large numbers of low-income or minority elders tended to have less education and commanded lower salaries than directors serving fewer poor and minority elders. In addition, while a higher proportion of these directors were minority members, numbers of nonwhite Nutrition Project Directors remains low.

Educational Status↗
PubMed1991

Amino acid sequence of Fel dI, the major allergen of the domestic cat: protein sequence analysis and cDNA cloning.

The complete primary structure of Fel dI (International Union of Immunological Societies nomenclature), the major allergen produced by the domestic cat, Felis domesticus, was determined by protein sequence analysis and cDNA cloning. Protein sequencing of Fel dI from an immunoaffinity-purified extract of house dust revealed that the allergen is composed of two polypeptide chains. Degenerate oligonucleotides derived from the protein sequence were used in polymerase chain reaction amplification of cat salivary gland cDNA to demonstrate that the two chains are encoded by different genes. Chain 1 of Fel dI shares amino acid homology with rabbit uteroglobin, while chain 2 is a glycoprotein with N-linked oligosaccharides.

Allergens↗
PubMed1991

Complete sequence of the allergen Amb alpha II. Recombinant expression and reactivity with T cells from ragweed allergic patients.

This study defines the complete primary structure of Amb alpha II, an important allergen produced by short ragweed (Ambrosia artemisiifolia). The deduced amino acid sequence derived from the cDNA indicates that Amb alpha II shares approximately 65% sequence identity with the Amb alpha I multigene family of allergens. Full-length cDNA encoding Amb alpha I.1 and Amb alpha II have been expressed in E. coli and purified. An in-frame linker encoding polyhistidine has been added to the 5' end of the cDNA to facilitate purification using Ni2+ ion affinity chromatography, yielding greater than 90% pure recombinant protein in a single step. T cells from patients allergic to ragweed proliferate in response to pollen extract as well as purified recombinant Amb alpha I.1 and Amb alpha II. T cell lines established using either Amb alpha I.1 or II as the stimulating Ag exhibit a high level of cross-reactivity to both proteins. This result is entirely consistent with the extensive primary sequence identity shared by these two proteins. These data suggest that allergic humans recognize shared T cell epitopes on these two related molecules.

Allergens↗
PubMed1991

Multiple Amb a I allergens demonstrate specific reactivity with IgE and T cells from ragweed-allergic patients.

The relationship between the structure and abundance of an inhaled protein and its potential for causing an allergic response is unknown. This study analyzes Amb a I, a family of related proteins formerly known as Ag E, that comprise the major allergens of short ragweed (Ambrosia artemisiifolia). T cells isolated from ragweed allergic patients were shown to proliferate in response to purified Amb a I.1 protein from pollen in in vitro secondary cultures, demonstrating the presence of T cell stimulatory epitopes in Amb a I.1. Three recombinant forms of Amb a I (Amb a I.1, Amb a I.2, and Amb a I.3) obtained as cDNA derived from pollen mRNA were expressed in bacteria. All three recombinant forms were shown to be specifically recognized by pooled ragweed-allergic human IgE on immunoblots, confirming these gene products are important allergens. An examination of immunoblots probed with sera derived from allergic patients revealed a variation in IgE binding specificity. A minority of patients' IgE exclusively reacted with recombinant Amb a I.1, whereas most patients' IgE reacted with Amb a I.1 as well as Amb a I.2 and Amb a I.3 proteins. A detailed examination of the reactivity of T cells derived from 12 allergic patients to these recombinant Amb a I forms revealed that these allergens are all capable of stimulating T cell proliferation in in vitro assays. It is concluded that the allergic response to ragweed pollen in most allergic patients is composed of a reaction to multiple related Amb a I proteins at both the B and T cell levels.

Allergens↗
PubMed1991

Cloning of Amb a I (antigen E), the major allergen family of short ragweed pollen.

To determine the structure of Amb a I (previously called antigen E), the major allergen from short ragweed, cDNA from pollen was cloned into lambda gt11 and lambda gt10. One of the three distinct clones isolated from the lambda gt11 library by screening with anti-denatured Amb a I antibodies was used to screen both libraries for other Amb a I sequences. Multiple clones were isolated and sequenced and proved to be highly homologous but nonidentical. The clones could be divided into three groups based on sequence similarity, and in accordance with the International Union of Immunological Societies-approved nomenclature (Marsh, D. G., Goodfriend, L., King, T. P., Lowenstein, H., and Platts-Mills, T. A. E. (1986) Bull. WHO 64, 767-770) they have been designated Amb a I.1, Amb a I.2, and Amb a I.3. Clones within a group have greater than 99% identity, and similarity among groups is 85-90% at the nucleotide level. The amino acid sequence of four peptides (isolated from antigen E obtained from the Research Resources Branch of the National Institutes of Health) containing 132 amino acids was identical to one of the clones (Amb a I.1). The presence of multiple naturally occurring isoelectric forms of Amb a I was demonstrated by two-dimensional gel electrophoresis and Western blotting. Southern blot analysis demonstrates the presence of multiple Amb a I-related sequences in the ragweed genome. Amb a I is therefore not a single molecule but rather a family of closely related proteins.

Allergens↗
PubMed1991

Sequence polymorphism of Amb a I and Amb a II, the major allergens in Ambrosia artemisiifolia (short ragweed).

Two of the major allergens in the pollen of short ragweed are Amb a I and Amb a II (formerly antigen E and antigen K, respectively). The genes for Amb a I and Amb a II have recently been cloned, and it was shown that Amb a I is a family of proteins with at least three distinct polymorphic family members. This study addresses the number of individual Amb a I and Amb a II family members, the polymorphism in each family member and the expression of these genes in ragweed plants from different geographical locations. This work led to the cloning and characterization of a fourth Amb a I family member, designated Amb a I.4.

Allergens↗
PubMed1989

School Breakfast Program and school performance.

To test the hypothesis that participation in the School Breakfast Program by low-income children is associated with improvements in standardized achievement test scores and in rates of absence and tardiness, children in grades 3 through 6 were studied in the Lawrence, Mass, public schools, where the School Breakfast Program was begun at the start of the second semester 1986-1987 school year. The changes in scores on a standardized achievement test and in rates of absence and tardiness before and after the implementation of the School Breakfast Program for children participating in the program were compared with those of children who also qualified but did not participate. Controlling for other factors, participation in the School Breakfast Program contributed positively to the 1987 Comprehensive Tests of Basic Skills battery total scale score and negatively to 1987 tardiness and absence rates. These findings suggest that participation in the School Breakfast Program is associated with significant improvements in academic functioning among low-income elementary school children.

Absenteeism↗