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M J Colston

Publications and source records attributed to M J Colston.

At least 109 records · Page 6Linked to original sources
PubMed1988

HLA-DR4 restricted lymphocyte proliferation to a Mycobacterium tuberculosis extract in rheumatoid arthritis and healthy subjects.

The ability of an antigenic extract of Mycobacterium tuberculosis to induce proliferation of PMBC from rheumatoid arthritis (RA) patients and normal controls was examined. The subjects were further classified as bearing or not bearing the HLA-DR4 phenotype, since this specificity is regarded as a genetic determinant commonly associated with RA. The mycobacterial extract induced significantly higher proliferative responses in lymphocytes from all HLA-DR4 positive as compared to HLA-DR4 negative subjects regardless of whether they had RA or not. This response was maximal at day 6 of incubation and could be abrogated by anti-DR/DQ mAb added to the culture. SDS-PAGE of this extract revealed three major protein bands located at Mr 14, 47, and 65 kDa. After fractionation, Western blotting, and resuspension of protein-laden nitrocellulose particles, only the 14- and 47-kDa proteins retained the original proliferative capacity of the mycobacterial extract. The band separating with a Mr of 47 kDa was found to be the most strongly associated with the HLA-DR4 restricted lymphocyte proliferation, and represents a newly identified M. tuberculosis Ag of relevance in T cell responses. These data provide insight into the pathogenic potential of certain bacterial Ag which could trigger or perpetuate inflammatory disorders when presented in the appropriate genetical background.

Antigens, Bacterial↗
PubMed1988

The processing and presentation of mycobacterial antigens by human monocytes.

The processing and presentation of whole irradiated Mycobacterium tuberculosis (Mtb gamma) and its purified protein derivative (PPD) by the peripheral blood monocytes from healthy Bacillus Calmette Guérin (BCG)-vaccinated individuals was investigated. To study processing and presentation as events distinct from T cell recognition and proliferation, monocytes were pulsed with antigens for varying time intervals and fixed. The kinetics of presentation indicate that up to 2 h was required for effective presentation of PPD and 2-4 h for Mtb gamma, and that the ability to activate T cells declined as the time interval for which pulsing occurred was increased, so that responses were abolished by 8-10 h. Prefixed monocytes could not present Mtb gamma and PPD to T cells indicating that processing was an essential requisite. Lysosomotropic agents chloroquine, monensin, and leupeptin inhibited the presentation of these antigens suggesting the role of lysosomes/endosomes in processing. Furthermore, monocytes incubated with optimal concentration of antigens for different lengths of time released determinants which were still antigenic but circumvented the need for any further processing. Addition of nonprimed syngeneic monocytes, both untreated or paraformaldehyde fixed to cells which had been pulsed and fixed, restored the responses even at the later time periods when responses were not detected. This second interaction of the monocyte with T cells was not major histocompatibility complex restricted in that the addition of monocytes from another donor was equally effective.

Antigen-Presenting Cells↗
PubMed1988

Partial nucleotide sequence of 16S ribosomal RNA isolated from armadillo-grown Mycobacterium leprae.

Ribosomal RNA (rRNA) was isolated from Mycobacterium leprae recovered from infected tissue of the Nine-banded Armadillo, and nucleotide sequences near the 3' end of the 16S species were determined by primer extension in the presence of dideoxynucleotides. Previously published data for bacterial 16S rRNAs show a pattern of conserved and non-conserved sequences that fit a common secondary structure. Our data for M. leprae fits this general pattern.

Animals↗
PubMed1988

Heterologous expression of the 65-kilodalton antigen of Mycobacterium leprae and murine T-cell responses to the gene product.

The gene encoding the immunodominant 65-kilodalton antigen of Mycobacterium leprae was subcloned from a lambda gt11 clone into the high-copy-number plasmid pUC8. Escherichia coli containing these recombinants produced large amounts of the antigen, which was purified by polyacrylamide gel electrophoresis in the presence of urea. The ability of E. coli to recognize the mycobacterial promoter was confirmed by constructing additional clones in which the gene is flanked by transcriptional terminators from phage fd. A similar approach was used to demonstrate the expression of this gene in Streptomyces lividans. Mice immunized with killed M. leprae showed cell-mediated immune reactivity to the purified 65-kilodalton protein which stimulated both in vitro lymphoproliferative and in vivo delayed-type hypersensitivity responses.

Animals↗
PubMed1987

Immunological activity of a 14-kilodalton recombinant protein of Mycobacterium tuberculosis H37Rv.

A 14-kilodalton peptide antigen from Mycobacterium tuberculosis was isolated from an Escherichia coli lambda gt 11 recombinant DNA clone and was identified by Western blotting (immunoblotting) with monoclonal antibody TB68. Immunization of mice and guinea pigs with the recombinant peptide (rTB68) induced in vitro lymphoproliferative responses in draining lymph node lymphocyte cultures as well as in vivo delayed-type hypersensitivity reactions. Moreover, rTB68 was found both to induce and to cross-react with Mycobacterium leprae immune lymphocytes, but did not generate protective effects against live M. leprae challenge in mice. These findings showed that a 14-kilodalton peptide which has been characterized as specific for M. tuberculosis on the basis of B-cell recognition was capable of generating cell-mediated immune responses and moreover contained T-cell epitopes which were cross-reactive with M. leprae antigens.

Antigens, Bacterial↗
PubMed1987

Limiting dilution analysis of the human T cell response to mycobacterial antigens from BCG vaccinated individuals and leprosy patients.

The number of peripheral blood T lymphocytes responding to soluble mycobacterial antigens from Mycobacterium tuberculosis purified protein derivative (PPD) and M. leprae (MLS) was estimated by limiting dilution analysis. Antigen-induced lymphocyte activation was measured by means of [3H]TdR incorporation on day 10 of culture in the presence of suboptimal concentrations of interleukin 2 (IL-2). In the peripheral blood of BCG-vaccinated individuals from the UK, the frequency of T lymphocytes responding to PPD was 1.5 to 4 times greater than to MLS. Frequencies between 1/1970 and 1/13, 982 were observed in response to PPD and between 1/4097 and 1/24, 717 in response to MLS. A proportion of cells in the peripheral blood were also observed to respond to IL-2 only. The frequency of cells observed in limiting dilution analysis for PPD and MLS reflected the relative amounts of proliferation to these two antigens in bulk culture lymphocyte transformation tests. Use of PPD-specific T cell lines suggested that the responsiveness observed to M. leprae antigens in BCG-vaccinated individuals was due to cross-reactivity with antigens shared with M. bovis BCG. In tuberculoid leprosy, the frequency of peripheral blood T lymphocytes responding to M. leprae antigens was either greater than or similar to the frequency of T cells responding to PPD. In contrast, limiting dilution analysis of T lymphocytes from the peripheral blood of lepromatous leprosy patients revealed the complex regulatory heterogeneity of this group. In some patients M. leprae responsive T cells were detected in the presence of exogenous IL-2.

Antigens, Bacterial↗
PubMed1986

Adenylate kinase activity in Mycobacterium leprae.

Adenylate kinase (ATP:AMP phosphotransferase, EC 2.7.4.3) was detected in partially purified preparations of cell-free extracts of Mycobacterium leprae. The apparent Km values of M. leprae adenylate kinase for ADP and Mg2+ were 1 X 10(-4) M, respectively. The enzyme was heat-labile: loss of activity by 80% at 45 degrees C and over 90% at 60 degrees C occurred within 5 min. M. leprae adenylate kinase was distinct from armadillo adenylate kinase in respect of affinity for substrate and heat-sensitivity.

Adenylate Kinase↗
PubMed1986

Investigation of antigen cross-reactivity of Mycobacterium leprae-reactive murine T-cell lines and clones.

Inguinal lymph node lymphocytes from BALB/c mice immunized intradermally with 10(8) 60Co-irradiated Mycobacterium leprae were cloned by limiting dilution culture. In general, cloned T-cell lines exhibited helper type activity producing interleukin-2, macrophage activation factor and gamma-interferon and lines were further characterized in terms of their cross-reactivities with other species of mycobacteria. M. leprae clones derived after a period of in vitro restimulation were found to cross-react with other species of mycobacteria probably recognizing non-specific or closely related common cell wall associated mycobacterial determinants. On the other hand, lines established by cloning directly from immune mice appeared more M. leprae-specific, exhibiting antigen-dependent lymphokine production and proliferation in vitro.

Animals↗
PubMed1985

Measurement of ATP generation and decay in Mycobacterium leprae in vitro.

The intracellular ATP content of Mycobacterium leprae isolated from armadillo tissue was approximately 1.5 X 10(-16) g per bacillus. During in vitro incubation of bacilli at 4 degrees C, 33 degrees C or 37 degrees C there was an exponential decrease in ATP content, the rate depending on the medium and the temperature. M. leprae incorporated phosphate into ATP and into other nucleotide materials during in vitro incubation.

Adenosine Triphosphate↗