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D P Harris

Publications and source records attributed to D P Harris.

14 recordsLinked to original sources
PubMed1992

T cell repertoire in tuberculosis: selective anergy to an immunodominant epitope of the 38-kDa antigen in patients with active disease.

It is generally accepted that both host protection and pathogenic reactions in tuberculosis are mediated by T lymphocytes. However, little is known about the structures and discreet functions of epitopes stimulating the immune response. In this study, proliferative responses of blood T lymphocytes to synthetic peptides derived from the sequence of the 38-kDa antigen from Mycobacterium tuberculosis have been investigated in 41 healthy individuals and in 36 patients with active tuberculosis. Of the healthy purified protein derivative (PPD)-positive donors, 90% responded to a permissively recognized peptide, 38.G (residues 350-359), located at the carboxy terminus of the molecule. Four other permissively recognized epitopes of this molecule (38.A, 38.I, 38.E, 38.K) were stimulatory for more than 50% of healthy PPD-positive individuals. Patients with lymphatic tuberculosis responded to these peptides in a similar manner. In contrast, we observed a selective anergy to stimulation with peptide 38.G in the majority of patients with pulmonary (11% responders) and nonlymphatic extrapulmonary tuberculosis (25% responders). The lack of responsiveness to 38.G was epitope specific since the degree of responsiveness to the other four permissively recognized peptide epitopes was similar for patients and PPD-positive controls. Using the PEPSCAN technology and truncated peptides, the core epitope of 38.G was localized to a peptide 10 amino acids long (HFQPLPPAVV). This minimal structure was capable of inducing a proliferative response in all healthy 38.G responders tested. The mechanisms influencing this epitope-specific anergy in patients could give new insights into the immunopathogenesis of tuberculosis.

Amino Acid Sequence↗
PubMed1992

Genetic control of immune responses to the 18-kDa protein of Mycobacterium leprae. Different TH1 subsets may be involved in proliferative and delayed-type hypersensitivity responses.

In vitro and in vivo responses to the 18-kDa protein of Mycobacterium leprae have been analysed in different strains of mice. Lymphocytes from BALB/cJ (H-2d), BALB.B (H-2b), B10.BR (H-2k), and B10.M (H-2f) mice primed with 18-kDa protein yielded high T cell proliferative responses, while those from C57BL/10J (H-2b) mice yielded lower responses. Both H-2 and non-H-2 genes contributed to the magnitude of responsiveness. F1 mice from high and low responder strains showed high responsiveness to the 18-kDa protein. Supernatants from lymph node cell cultures prepared from 18-kDa protein-immunised BALB/cJ, B10.BR, and C57BL/10J mice contained IL-2 but no IL-4, indicating that activated T cells from both high and low responder mice were of a TH1 phenotype. Cell cultures from low responder C57BL/10J mice produced less IL-2 than those from high responders. The low responsiveness to the 18-kDa protein in proliferative assays might be due to a low frequency of antigen-specific T cells in the C57BL/10J mouse strain. BALB/cJ, C57BL/10J, and F1 (BALB/cJ x B10.BR) mouse strains were tested for in vivo DTH reactions to the 18-kDa protein. All strains, including C57BL/10J, were high DTH responders. Although DTH effector cells and 18-kDa protein-specific proliferative T cells belong to the TH1 subset, our data comparing high and low responder status indicate that distinct TH1 subpopulations are stimulated in response to the 18-kDa protein of M. leprae.

Animals↗
PubMed1992

M. tuberculosis-complex specific T-cell stimulation and DTH reactions induced with a peptide from the 38-kDa protein.

An immunodominant T-cell-stimulatory epitope located near the carboxy terminus of the 38-kDa antigen from M. tuberculosis (38.G, residues 350-369) was found to be M. tuberculosis-complex specific. This was demonstrated by the presence of proliferative and delayed type hypersensitivity (DTH) responses in mice immunized with Mycobacterium tuberculosis and Mycobacterium bovis BCG, whereas mice immunized with M. avium or other non-tuberculous species of mycobacteria showed no such responses. Peptide 38.G stimulated the proliferation of peripheral blood lymphocytes from healthy purified protein derivative (PPD)-positive individuals but not from PPD-negative individuals. It also elicited DTH responses in M. tuberculosis sensitized mice and in PPD-positive healthy human volunteers. Peptide 38.G could therefore prove to be an important component in any new molecularly defined reagent used in the immunodiagnosis of tuberculous infection.

Amino Acid Sequence↗
PubMed1991

Murine T cell-stimulatory peptides from the 19-kDa antigen of Mycobacterium tuberculosis. Epitope-restricted homology with the 28-kDa protein of Mycobacterium leprae.

Fifteen overlapping synthetic peptides, spanning the entire amino acid sequence of the Mycobacterium tuberculosis 19-kDa protein, were used to identify epitopes recognized by murine T cells. Five of the 15 peptides tested were able to elicit in vitro lymph node T cell proliferative responses in C57BL/10 mice primed by footpad inoculation with homologous peptide. Analysis in congenic strains of mice revealed H-2 restriction in the response to four peptides. However, one peptide, 19.7 (residues 61 to 80), induced T cell responses in all four haplotypes tested. This peptide was also unique in being able to stimulate lymph node cells from C57BL/10 mice immunized with recombinant 19-kDa protein, killed M. tuberculosis, or live bacillus Calmette Guerin infection. T cell lines specific for peptide 19.7 were of the CD4 phenotype. Significantly, sequence analysis revealed that residues 61 to 80 of the 19-kDa protein exhibited considerable homology with a single 20-amino acid sequence (residues 120 to 140), but not with any other region of the 28-kDa protein expressed in Mycobacterium leprae. This finding is the first evidence of epitope-restricted homology between otherwise structurally unrelated microbial Ag.

Amino Acid Sequence↗
PubMed1991

Identification of T cell stimulatory peptides from the 38-kDa protein of Mycobacterium tuberculosis.

T cell specificity to individual antigenic epitopes could determine the distinction between protective and pathogenic host reactions in tuberculous infections. Therefore, T cell stimulatory epitopes of the Mycobacterium tuberculosis 38-kDa lipoprotein, of known structure and specificity and of prominent immunogenicity, have been examined. To identify potential T cell epitopes, eight peptides, seven of which were predicted to form amphiphatic helices, were used for immunization of various inbred mice and for elicitation of in vitro T cell proliferative responses. Three different response patterns were observed. 1) Lymph node cells from mice immunized with peptide, recombinant 38-kDa Ag, killed M. tuberculosis strain H37Ra, or live Mycobacterium bovis bacillus Calmette Guerin infection responded to peptide 38.G (residues 350 to 369). Responses were observed in mice of H-2b, H-2d, and H-2k haplotypes. 2) Peptide 38.C (residues 201 to 220) induced proliferation of lymph node cells from 38-kDa protein-, but not from peptide-immunized mice. 3) Peptide 38.F (residues 285 to 304) only elicited a response of the homologous peptide-primed cells. Analysis of CD4+ T cell lines confirmed the distinct specificities and stimulatory features of peptides 38.F and 38.G. The described attributes of peptide 38.C and 38.G could be of potential interest for diagnostic evaluation in tuberculous infections.

Amino Acid Sequence↗
PubMed1990

Feasibility of auditory event-related potential measurement in brain injury rehabilitation.

Measurements of auditory event-related potentials (AERPs) from brain injury rehabilitation patients may provide information on neural function related to cognitive processes important to the recovery of social and intellectual skills. The present study investigated the feasibility of measuring AERPs from 50 brain injury rehabilitation inpatients at various stages of cognitive recovery including comatose to automatic-appropriate function. Patients from levels II through VII on the Rancho Los Amigos Scale of Cognitive Function were studied. Results indicated that waveforms showing N1, P2, N2, and P3 components could be recorded from individual patients at each of the RLAS levels we studied, except level IV where only 1 patient was tested. However, considerable variability in waveforms was also observed at each scale level. No statistically significant relationships were demonstrated between AERP components and all other evoked potential, central auditory, and audiometric test results for 30 patients at RLAS level VII (automatic-appropriate). Overall results suggested a need for research focused on electrophysiologic and behavioral measures that can be used in conjunction to better describe auditory function and prognosis in brain injury patients.

Adolescent↗
PubMed1989

The mapping of epitopes of the 18-kDa protein of Mycobacterium leprae recognized by murine T cells in a proliferation assay.

The 18-kDa protein of Mycobacterium leprae was purified from recombinant plasmids pUL108 and pML-3 grown in Saccharomyces cerevisiae and Escherichia coli, respectively. Significant lymphoproliferative responses were observed when T cells from immunized mice were challenged in culture with purified 18-kDa protein. Synthetic peptides have been prepared that span most of the 148 amino acid residues that constitute the sequence of the 18-kDa protein and used to map epitopes recognized by T cells. When mice were immunized with 18-kDa protein and lymph node cells subsequently prepared and challenged in microculture proliferative assays by using synthetic peptides, only one region of the intact protein appeared stimulatory. This T cell epitope was located between residues 116 and 121, adjacent to an epitope between residues 110 and 115 which we have previously shown to bind the L5 mAb. Immunization of mice with peptides, and subsequent challenge of lymph node cells in assays by using the 18-kDa protein as Ag revealed that residues 111-125 were the most effective in priming responses. Furthermore, the ability of 18-kDa primed lymph node cells to recognize determinants on both M. leprae and Mycobacterium tuberculosis indicates that in addition to possessing an M. leprae-specific B cell determinant, the 18-kDa protein contains a cross-reactive T cell epitope(s).

Amino Acid Sequence↗
PubMed1988

Genetic control of murine T cell proliferative responses to Mycobacterium leprae. V. Evidence for cross-reactivity between host antigens and Mycobacterium leprae.

T cell proliferative responses to Mycobacterium leprae were measured by immunization of mice at the base of the tail with Ag and challenging lymphocytes from draining lymph nodes in culture with M. leprae. C57BL/10J and B10.BR mice were identified as low responder mice and the congenic strains B10.M, B10.Q, and B10.AKM as high responders whereas F1 (high x low) hybrid mice were found to be low responders. The cellular basis of low responsiveness did not appear to result from a defect in Ag-presenting cells or the activation of suppressor T cells by M. leprae. The influence of the environment in which T cells developed on responsiveness to M. leprae was analyzed in chimeric mice prepared by irradiating F1(C57BL/10J x B10.M) mice and reconstituting with bone marrow from C57BL/10J, B10.M, or F1 donors. Six weeks later, chimeric mice were immunized with M. leprae, lymph node cells were subsequently prepared, and H-2 phenotyped and challenged in culture with M. leprae Ag. T cell proliferative responses were found to be low in all cases, similar to those observed using lymph node cells from F1 hybrid mice. These results suggested that high responder B10.M lymphocytes developing in the irradiated F1 mice became tolerized to antigenic determinants found on M. leprae. This implied cross-reactive epitopes existed between some mouse strains and M. leprae. Low responsiveness to M. leprae in low responder and F1 hybrid mice may result from tolerance to H-2-encoded Ag that show cross-reactivity with M. leprae.

Animals↗
PubMed1988

Antigenic proteins of Mycobacterium leprae. Complete sequence of the gene for the 18-kDa protein.

Recombinant clones expressing antigenic determinants of the 18-kDa protein antigen from Mycobacterium leprae recognized by the L5 monoclonal antibody were isolated from a lambda gt11 expression library and their nucleotide sequences determined. All clones expressed the M. leprae-specific determinant as part of a large fusion protein with Escherichia coli beta-galactosidase. The deduced amino acid sequence of the coding region indicated that all the lambda gt11 recombinant clones contained an incomplete M. leprae gene sequence representing the carboxy-terminal two-thirds (111 amino acids) of the 18-kDa gene and coding for a peptide of m.w. 12,432. Subsequent isolation and sequencing of a 3.2kb BamHI-PstI DNA fragment from a genomic M. leprae cosmid library permitted the deduction of the complete 148 amino acid sequence with a predicted m.w. of 16,607. A second open reading frame 560 bases downstream from the 18-kDa coding sequence was found to code for a putative protein of 137 amino acids (m.w. = 15,196). Neither this nor the 18-kDa amino acid sequence displayed any significant homologies with any proteins in the GENBANK, EMBL, or NBRF data bases. Crude lysates from recombinant lambda gt11 clones expressing part of the 18-kDa protein have been reported to stimulate the proliferation of some M. leprae-specific helper T cell clones. Thus, it is significant that the complete 18-kDa sequence contains five short peptides predicted to be possible helper T cell antigenic epitopes based on their propensity to form amphipathic helices. Although three of these occur within the 111 amino acid carboxy-terminal peptide expressed by lambda gt11 clones, the most highly amphipathic peptide is found in the amino-terminal region not present in the lambda gt11 recombinants.

Amino Acid Sequence↗
PubMed1988

A simple microcomputer interface for tail-flick determination.

An inexpensive means of tail-flick latency data acquisition and analysis using an Apple IIe microcomputer and three simple interface circuits is described. Descriptions of the software and hardware are provided with schematics and program listings. The measurement, storage, and analysis of the data are integrated in one system.

Animals↗
PubMed1987

Residential treatment of disturbed delinquents: description of a centre and identification of therapeutic factors.

Residential treatment for disturbed, particularly delinquent, adolescents has been described several decades ago by the founders and leaders of institutions. Theoretical considerations in treatment were prominent. The importance of structured milieu and the control of aggression came to acquire recognition. This study describes a structured centre, known to be effective in treating disturbed delinquents, using data gathered over twelve years of clinical work, observation and research. Factors considered essential in defining this institution are isolated and made compatible with the factors indicated by Rutter in his review of the residential treatment of delinquents. These factors are being used in a further study which compares the effectiveness of different types of facilities for a range of diagnostic categories.

Adolescent↗
PubMed1986

A psychometric evaluation of a residential treatment facility: an illustration of an interpretable research design without a control group.

This paper reports on the interim results of an evaluation study which followed a group of disordered-delinquent adolescents discharged from a long-term residential treatment program. Findings from the first cohort of adolescents tested at admission and discharge with the Tennessee Self-Concept Scale (TSCS) indicate statistically significant improvement in all the areas of self-concept, significant decreases in all areas of psychopathology, and no systematic response set at either testing. The research design is unique in that, without a control group, competing interpretations of treatment effectiveness have been ruled out. Using design features, clinical observation, and common sense, four competing explanations of the favorable results have been eliminated. Both the instrument and research design are of interest to those undertaking evaluation research in underfunded settings where control groups are difficult to obtain due to financial or logistical problems.

Adolescent↗