PubMed Health⌕ Search

Biomedical subjects

K Huygen

Publications and source records attributed to K Huygen.

At least 73 records · Page 4Linked to original sources
PubMed1996

Immunogenicity and protective efficacy of a tuberculosis DNA vaccine.

Tuberculosis is the most widespread and lethal infectious disease affecting humans. Immunization of mice with plasmid DNA constructs encoding one of the secreted components of Mycobacterium tuberculosis, antigen 85 (Ag85), induced substantial humoral and cell-mediated immune responses and conferred significant protection against challenge with live M. tuberculosis and M. bovis bacille Calmette-Guérin (BCG). These results indicate that immunization with DNA encoding a mycobacterial antigen provides an efficient and simple method for generating protective immunity and that this technique may be useful for defining the protective antigens of M. tuberculosis, leading to the development of a more effective vaccine.

Animals↗
PubMed1995

Fibronectin-binding antigen 85 and the 10-kilodalton GroES-related heat shock protein are the predominant TH-1 response inducers in leprosy contacts.

Peripheral blood mononuclear cells from 27 healthy leprosy contacts were analyzed for lymphoproliferation and TH-1 cytokine secretion (interleukin-2 and gamma interferon) in response to heat shock proteins with molecular masses of 65, 18, and 10 kDa from Mycobacterium leprae and the 30-32-kDa antigen 85 (Ag 85) from Mycobacterium bovis BCG. Cells from 18 and 19 of 19 lepromin-positive contacts proliferated or produced TH-1 cytokines in response to the M. leprae 10-kDa protein and to Ag 85, respectively. Limiting-dilution analysis for two lepromin-positive contacts indicated that about one-third of M. leprae-reactive T cells displayed specificity to the M. leprae 10-kDa protein and Ag 85. The M. leprae 65- and 18-kDa proteins were less potent TH-1 response inducers: gamma interferon and interleukin-2 could be measured in 14 and 19 lepromin-positive contacts, respectively. In contrast, very low or undetectable proliferative and cytokine responses were found for 8 lepromin-negative contacts. Our data demonstrate that the fibronectin-binding Ag 85 and the 10-kDa GroES homolog are powerful mycobacterial TH-1 response inducers in the vast majority of lepromin-positive contacts and suggest that they might be valuable candidates for a future subunit vaccine.

Adolescent↗
PubMed1994

T cell reactivity against antigen 85 but not against the 18- and 65-kD heat shock proteins in the early stages of acquired immunity against Mycobacterium leprae.

T cell proliferation and interferon-gamma (IFN-gamma) production of peripheral blood mononuclear cells (PBMC) from 20 household contacts were tested against the 18- and 65-kD heat shock proteins from Mycobacterium leprae (ML18 and ML65 respectively) and antigen 85 from Myco. bovis bacille Calmette-Guérin (BCG) (Ag 85) during a 12-months follow-up study. Among the eight contacts that became positive, eight showed positive reactivity against Ag 85, 5/8 against ML65 and 4/8 against ML18 at the end of the study. Of the 16 contacts who were lepromin-positive either at first or second testing, all responded to Ag 85, 11 to ML 65, but only eight reacted to ML18 antigen. Contacts who were lepromin-positive at first testing developed responses to ML18 only at second testing. In contrast, among the four contacts that remained lepromin-negative during the follow up, three proliferated to Ag 85 either at first or second testing, but only one produced IFN-gamma against Ag 85 at the end of the study. These results demonstrated that T cell reactivity and particularly IFN-gamma secretion against Ag 85, but not against ML18 and ML65, might be a predominant mechanism in the early stages of acquired protective immunity against Myco. leprae.

Adolescent↗
PubMed1994

IgG humoral response against the antigen 85 complex homologues in leprosy.

Antigen 85 complex is the major protein component present in M. bovis BCG culture filtrate (CF). It consists of a family of three proteins: 85A, 85B and 85C. Combining isoelectric focusing and Western blot analysis, we have previously identified different antigenically related proteins present in the CF of other mycobacteria (M. tuberculosis, M. kansasii, M. avium, M. gordonae, M. fortuitum and M. phlei) using monoclonal antibodies (MoAbs) directed against the antigen 85 complex of M. bovis BCG. Humoral immune response directed against these cross-reactive homologues was analysed in sera from 20 patients with multibacillary leprosy (BL/LL), from 20 patients with paucibacillary leprosy (BT/TT) and from 15 healthy leprosy contacts. All the antigen 85 homologues identified in the seven CFs by MoAbs were also recognized by IgG present in sera from multibacillary leprosy patients, but not or very faintly in sera from paucibacillary leprosy patients or from healthy subjects. These results suggest that some of the M. leprae epitopes inducing a significant humoral response in multibacillary leprosy are common to the various 85 antigenically related proteins present in all mycobacterial species.

Antibodies, Bacterial↗
PubMed1994

Mapping of TH1 helper T-cell epitopes on major secreted mycobacterial antigen 85A in mice infected with live Mycobacterium bovis BCG.

TH1 cytokine secretion was examined in response to synthetic peptides of the 85A component of the major secreted, fibronectin-binding antigen 85 complex from Mycobacterium tuberculosis in seven different mouse strains infected with live M. bovis BCG. Twenty-eight overlapping 20-mer peptides covering the complete mature 295-amino-acid (AA) protein were synthesized. Significant interleukin-2 (IL-2) and gamma interferon (IFN-gamma) secretion could be measured following in vitro stimulation of spleen cells with these peptides. H-2d haplotype mice reacted preferentially against the amino-terminal half of the protein, i.e., against peptide 5 (AA 41 to 60) and especially against peptide 11 (AA 101 to 120), which contained an I-Ed binding motif. H-2b haplotype mice, on the other hand, reacted against peptides from both amino- and carboxy-terminal halves of the protein, peptide 25 (AA 241 to 260) being the most potent stimulator of IL-2 and IFN-gamma production. (BALB/c x C57BL/6)F1 animals with the H-2d/b haplotype weakly recognized peptides specific for both parental lines. Finally, CBA/J (H-2k) and major histocompatibility complex class II mutant B6.C.bm12 mice, carrying a mutant I-A beta bm12 allele on an H-2b background, reacted only very weakly to the 85A peptides. Reactive T cells isolated from lungs of BCG-infected H-2b haplotype mice recognized the same epitopes as spleen cells, especially peptide 25. These data confirm previous findings regarding the powerful IL-2 and IFN-gamma-inducing properties of antigen 85 during infection with live M. bovis BCG.

Amino Acid Sequence↗
PubMed1994

Structure of the Mycobacterium tuberculosis antigen 88, a protein related to the Escherichia coli PstA periplasmic phosphate permease subunit.

We report the cloning and sequencing of the gene coding for antigen 88 from Mycobacterium tuberculosis by using monoclonal antibodies to screen an expression library in lambda gt11. The gene encodes a 403-amino-acid-residue protein with a calculated molecular mass of 43,790 Da which contains seven putative transmembrane alpha-helical domains and presents a significant homology to the PstA protein of Escherichia coli. In its N-terminal region, it contains a 61-amino-acid region highly homologous to the fifth transmembrane helix of E. coli PstC. PstA and PstC are the two hydrophobic subunits of an E. coli periplasmic phosphate permease. Since the phosphate-binding subunit of this putative permease in M. tuberculosis has previously been characterized, i.e., the 38-kDa mycobacterial protein (also called protein antigen b, Ag 5, and Ag 78) homologous to PstS of E. coli, it seems likely that functional permeases analogous to the periplasmic permeases of gram-negative bacteria also exist in mycobacteria.

ATP-Binding Cassette Transporters↗
PubMed1994

T-cell-epitope mapping of the major secreted mycobacterial antigen Ag85A in tuberculosis and leprosy.

Lymphoproliferation and gamma interferon (IFN-gamma) secretion in response to 28 overlapping 20-mer synthetic peptides covering the complete sequence of the mature (295-amino-acid) 85A component of the major secreted, fibronectin-binding antigen 85 complex from Mycobacterium tuberculosis and Mycobacterium bovis BCG (MTAg85A) was examined by using peripheral blood mononuclear cell (PBMC) cultures from healthy tuberculin- and lepromin-positive volunteers and from patients with tuberculosis and leprosy. Peptide recognition was largely promiscuous, with a variety of human leukocyte antigen haplotypes reacting to the same peptides. PBMC from all tuberculin-positive subjects reacted to Ag85, and the majority proliferated in response to peptide 6 (amino acids 51 to 70), peptides 13, 14, and 15 (amino acids 121 to 160), or peptides 20 and 21 (amino acids 191 to 220). PBMC from tuberculosis patients demonstrated a variable reactivity to Ag85 and its peptides, and the strongest proliferation was observed against peptide 7 (amino acids 61 to 80). MTAg85A peptides were also recognized by PBMC from healthy lepromin-positive volunteers and paucibacillary leprosy patients (again in a promiscuous manner), but despite a 90% homology between the 85A proteins of M. leprae and M. tuberculosis, the peptides recognized were different. PBMC from lepromin-positive healthy contacts reacted against peptide 2 (amino acids 11 to 30), peptide 5 (amino acids 41 to 60), and peptides 25 and 26 (amino acids 241 to 270). PBMC from paucibacillary patients reacted preferentially against peptide 1 (amino acids 1 to 20) and peptide 5. Multibacillary patients were not reactive to Ag85 or the MT85A peptides. IFN-gamma production was generally detected simultaneously with positive lymphoproliferative responses, although peptide 1 mostly stimulated proliferation and peptides 27 and 28 mostly elicited an IFN-gamma response. In conclusion, regions 41 to 80 and 241 to 295 demonstrated powerful and promiscuous T-cell-stimulatory properties, resulting in proliferative responses and IFN-gamma secretion, respectively, in the majority of reactive subjects tested in this study. These results could be of value in the development of a subunit vaccine for tuberculosis and leprosy.

Amino Acid Sequence↗
PubMed1994

Evolution of cellular and humoral response against Tuberculin and antigen 85 complex during intravesical treatment with BCG of superficial bladder cancer.

Prophylactic treatment with Bacillus Calmette-Guerin (BCG) is an established and effective therapy of bladder cancer. The antitumor effect of BCG seems to be largely related to cellular immunological mechanisms, although its precise mode of action is unknown. Antitumor response of BCG seems to be initiated by the attachment of BCG to bladder wall via Fibronectin (FN). The cellular immune response against Tuberculin PPD and the major secreted BCG antigen (Fibronectin-binding AG 85 complex) has been tested in a control group of 20 untreated bladder tumor patients and before and after 6 weekly intravesical BCG instillations in a group of 20 superficial bladder tumor patients. A major increase in the lymphoproliferative response against PPD and AG 85 was observed in respectively 66% and 57% of the treated patients. In contrast, no detectable antibody response (IgA, IgM, IgG) was observed against AG 85 complex after BCG treatment. On the other hand, antibodies against Tuberculin increased in 13 of 20 patients. This study seems to demonstrate a specific cellular immune activation against AG 85 Fibronectin-binding complex during BCG treatment of superficial bladder tumors. Humoral response against the AG 85 is not activated after BCG treatment. Further studies are needed to elucidate the role of AG 85 in the cellular intravesical penetration of BCG. Presence or absence of cellular response against this antigen could be of clinical value.

Administration, Intravesical↗
PubMed1994

IgG response to purified 65- and 70-kDa mycobacterial heat shock proteins and to antigen 85 in leprosy.

IgG antibody response to mycobacterial heat-shock proteins (hsp) (the 70-kDa antigen from Mycobacterium tuberculosis and M. bovis BCG; the 65-kDa antigen from M. leprae and M. bovis BCG) and to the fibronectin-binding antigen 85 from M. bovis BCG was analyzed in a dot-blot assay in plasma from leprosy patients and their contacts. Most plasma--whatever the status of the subjects--reacted to the hsp 70; 8 of 9 (89%) of paucibacillary patients recognized the 65 mycobacterial hsp but only 2 of 9 (22%) recognized the antigen 85. In contrast, 12 of 12 (100%) of multibacillary patients reacted with the antigen 85 and only 4 of 12 (33%) reacted to the hsp 65 from M. leprae. On the one hand, 7 of 25 (28%) of the lepromin-positive contacts and 2 of 9 (22%) of the lepromin-negative contacts recognized the antigen 85. On the other hand, 11 of 25 (44%) of the lepromin-positive contacts but only 1 of 9 (11%) of the lepromin-negative contacts reacted to the hsp65 from M. leprae. Finally, very few (10%) of the lepromin-positive controls showed a positive reaction to the M. leprae 65-kDa antigen, the BCG 65-kDa antigen, and the 85-kDa antigen of BCG. Thus, differences in binding to the hsp65 from M. leprae and to antigen 85 could be helpful in distinguishing different forms of the disease.

Antibodies, Bacterial↗
PubMed1993

Successful alpha-2b-interferon therapy for chronic neutrophilic leukemia.

The authors report two patients with characteristic features of chronic neutrophilic leukemia (CNL) treated with alpha-2b-interferon (IFN) (Schering-Plough). At initiation of therapy, both patients had progressive disease and presented with large tumors. A rapid reduction of the tumor mass and a long-term stabilisation of the myeloproliferative disorder was obtained (therapy duration 16 and 26 months, respectively, and presently ongoing). In one patient, the dose of IFN could be significantly reduced during maintenance without relapse. Neither presented infectious or hemorrhagic complications under therapy. Alpha-2b-interferon is active and safe in CNL, even pretreated and progressive. It can also correct the neutrophil and natural killer functional defects frequently observed in CNL.

Aged↗
PubMed1993

TH2 activated cells prevent experimental autoimmune uveoretinitis, a TH1-dependent autoimmune disease.

Mercuric chloride (HgCl2) injections protect (Lewis x Brown-Norway) F1 (F1) rats against experimental autoimmune uveoretinitis (EAU) induced by immunization with the retinal S antigen (S-Ag); in contrast HgCl2-injected F1 rats develop EAU following transfer of lymph node (LN) cells from rats immunized with S-Ag alone. In the present study we demonstrate that the ability of LN cells from rats protected against EAU to transfer the disease into naive F1 rats was considerably reduced. These LN cells neither produced interleukin (IL)-2 nor (interferon (IFN)-gamma but exhibited mRNA for IL-4. In contrast, LN cells from diseased rats easily transferred EAU into naive F1 rats, produced significant IL-2 and IFN-gamma levels but barely exhibited mRNA for IL-4. Furthermore protected rats predominantly produced IgG1 anti-S-Ag antibodies, while diseased rats produced IgG2b anti-S-Ag antibodies and the increase in expression of MHC class II molecules on B cells was higher in protected rats than in diseased rats. These data suggest that (1) to exert a protective effect, HgCl2 must act at an early stage of differentiation of precursors of S-Ag specific T cells, and (2) this effect is related to the preferential activation of TH2 cells to the detriment of uveitogenic TH1 cells. Finally, these results indicate that activation of TH2 cells protect from a TH1-dependent autoimmune disease.

Animals↗
PubMed1993

IL-6 production in response to purified mycobacterial heat-shock proteins and to antigen 85 in leprosy.

IL-6 production was examined in PBMC cultures from healthy leprosy contacts and from leprosy patients stimulated with the purified mycobacterial 18-, 65-, and 70-kDa heat-shock proteins (hsp) and the secreted fibronectin-binding antigen 85 (Ag85). In lepromin-negative contacts, the 70-kDa hsp was the only antigen capable of eliciting significant IL-6 production. In lepromin-positive contacts, Ag85, the 65- and the 70-kDa hsp induced substantial IL-6 titers. IL-6 levels induced with the 70-kDa antigen were about fourfold higher than with the 65-kDa hsp or with Ag85. The 18-kDa antigen did not induce any IL-6 in these healthy contacts. PBMC from tuberculoid leprosy patients produced even more elevated levels of IL-6, and PBMC from lepromatous leprosy patients produced extremely high levels of IL-6. All antigens were capable of inducing IL-6 in leprosy patients. Highest levels were found in cultures stimulated with the 65-kDa hsp, and lowest levels were in cultures stimulated with the 18-kDa hsp.

Antigens, Bacterial↗
PubMed1993

The major secreted antigen complex (Ag 85) from Mycobacterium bovis bacille Calmette-Guérin is associated with protective T cells in leprosy: a follow-up study of 45 household contacts.

T cell proliferation and interferon (IFN)-gamma secretion were analyzed in 45 leprosy contacts stimulated with antigen 85 (Ag85), the major culture filtrate antigen from Mycobacterium bovis bacille Calmette-Guérin. All 14 Mitsuda reaction-positive contacts reacted to Mycobacterium leprae and Ag85. Three Mitsuda reaction-negative contacts reacted weakly to M. leprae and Ag85. The other 28 Mitsuda reaction-negative contacts did not react to M. leprae, but 9 reacted to Ag85. Thirty-four contacts were retested 16 months later. Eleven contacts initially positive by the Mitsuda test remained lepromin positive and reactive to M. leprae and Ag85. Fourteen contacts initially negative by the Mitsuda test converted, and all reacted in vitro to M. leprae and Ag85. Finally, 9 contacts remained Mitsuda test-negative, and 7 were unreactive to Ag85. In vitro reactivity to Ag85 at baseline in Mitsuda test-negative contacts was associated with subsequent conversion to lepromin reactivity in 7 of 9 subjects. These data suggest that reactive T cells against Ag85 develop very early during M. leprae infection and that Ag85 is a potentially protective T cell immunogen.

Adolescent↗
PubMed1993

Anti-renin T cells trigger normal B cells to produce anti-renin antibodies and normalize blood pressure in spontaneously hypertensive rats.

Spontaneously hypertensive (SH) rats immunized with mouse renin produce anti-renin antibodies, responsible for down-modulation of blood pressure, associated with an infiltration of kidneys by mononuclear cells. In this work, anti-renin T cells from SH rats immunized with renin have been stimulated in vitro, and we have studied in vitro and in vivo their effect on anti-renin antibody production by normal syngeneic B cells. We show that, in vitro, renin-activated T cells induce a renin-specific antibody response without addition of exogenous renin. Anti-renin T cells injected into naive SH rats trigger normal B cells to secrete high amounts of monospecific anti-renin IgG antibodies as early as day 5. These antibodies interfere with the homeostasis of the renin-angiotensin system leading to the normalization of blood pressure without any nephritis. These results show that anti-renin B cells are either not tolerant per se or in a reversible state of anergy. Our results also suggest that anti-renin B cells constitutively express renin-derived peptides in such a way that they may be stimulated by activated anti-renin T cells; these cells express IL-4 mRNA indicating that IL-4 could play a role in the differentiation of B cells.

Animals↗
PubMed1993

T-cell stimulation with purified mycobacterial antigens in patients and healthy subjects infected with Mycobacterium leprae: secreted antigen 85 is another immunodominant antigen.

Peripheral blood leucocytes from 9 paucibacillary and 12 multibacillary leprosy patients, from 18 healthy controls and from 34 healthy leprosy contacts were stimulated with three mycobacterial heat shock proteins with respective molecular weights of 70, 65 and 18 kDa and with the secreted 30-32 kDa protein, also called antigen 85. Antigen 85 was found to be the most powerful T-cell antigen (as measured by lymphoproliferation and IFN-gamma secretion), eliciting a positive response in all (100%) paucibacillary patients and in all lepromin-positive controls and contacts. The three heat shock proteins (hsp) were less active T-cell stimuli. Reactivity to the 70 kDa hsp was found in only 44% of the paucibacillary patients, in 80% of the lepromin-positive controls and in 60% of the lepromin-positive leprosy contacts. The 65 kDa hsp stimulated T cells in 89% of the paucibacillary patients and in 80% of the lepromin-positive controls and contacts. Responsiveness to the 18 kDa hsp, finally, was clearly more frequent in tuberculoid leprosy patients (78%) than in lepromin-positive controls (40%) or lepromin-positive leprosy contacts (4%). T-cell reactivity of 8 lepromin-negative controls, of 9 lepromin-negative contacts and of 12 multibacillary leprosy patients was low to all the antigens tested. Although proliferative and IFN-gamma responses were generally closely related, some subjects demonstrated a dissociation of these two immune parameters. Our data confirm previous findings on the powerful T-cell stimulatory properties of antigen 85 during M. leprae infection and suggest that this antigen is indeed a potentially protective T-cell immunogen.

Antigens, Bacterial↗
PubMed1993

Influence of genes from the major histocompatibility complex on the antibody repertoire against culture filtrate antigens in mice infected with live Mycobacterium bovis BCG.

C57BL/10 and C57BL/6 mice (H-2b); B10 congenic mice with f, k, p, q, r, and s H-2 haplotypes; B10 mice with recombinant g2, o2, a, h2, h4, i5, and bq1 H-2 haplotypes; and B6 mice with major histocompatibility complex (MHC) mutant bm1 and bm13 (class I) and bm12 (class II) haplotypes were infected intravenously with 4 x 10(6) CFU of live Mycobacterium bovis BCG and examined by Western immunoblot analysis for serum antibodies against BCG culture filtrate antigens, following a boost injection with live BCG or with BCG culture filtrate. Parental B10 and B6 mice reacted very intensely with three culture filtrate protein bands with estimated molecular masses of 37, 38, and 40 kDa. Response against the 40-kDa protein was stronger following a boost injection with live BCG than following a boost with culture filtrate. Sera from mice with f, p, i5, bm1, and bm13 haplotypes reacted strongly, with both the 37-38- and 40-kDa antigens, and sera from mice with q and bq1 haplotypes showed a somewhat weaker reaction. Sera from mice with r, s, and bm12 haplotypes reacted against the 37-38-kDa antigen but not against the 40-kDa antigen, and sera from mice with the h2 haplotype reacted only with the 40-kDa antigen but not with the 37-38-kDa antigen. Sera from mice with the k, g2, o2, a, and h4 haplotypes showed, at most, a very weak reaction with the 37-38- and 40-kDa antigens. These results demonstrate that MHC genes profoundly affect the antibody repertoire used against culture filtrate antigens in mice infected with live M. bovis BCG. In particular, as shown in mice with the recombinant H-2 haplotype and in class II mutant bm12 mice, the I-A heterodimer controls the recognition of the immunodominant 40-kDa antigen. By using crossed immunoelectrophoresis, this 40-kDa antigen was identified as antigen 88 according to the reference system of Closs et al. for BCG antigens.

Animals↗
PubMed1993

Detection of mycobacterial antigens present in short-term culture media using particle counting immunoassay.

Particle counting immunoassay (PACIA) was compared with the BACTEC system for detecting mycobacterial growth after short-term culture and was used to identify M. tuberculosis. The latex particles were coated with polyclonal anti-BCG or with specific 2A1-2 monoclonal antibodies. Bottles containing nonradioactive Middlebrook 7H9 liquid medium and BACTEC 12B vials were inoculated with equal amounts of mycobacteria from four reference strains (M. tuberculosis, M. kansasii, M. avium, and M. xenopi). Using anti-BCG, PACIA detected mycobacterial antigens 3 to 6 days before the BACTEC system. M. tuberculosis was differentiated from the other mycobacteria using 2A1-2. Seventeen clinical samples were also studied. In the same 10, the two techniques detected mycobacteria, PACIA with anti-BCG after 9 days and BACTEC 1 to 5 days later. For 9 of the 10 samples, PACIA with 2A1-2 detected M. tuberculosis after 20 days, a result confirmed with the AccuProbe system. M. xenopi was biochemically identified in Specimen 10. Nonmycobacterial diseases were diagnosed in the 7 remaining unreactive specimens. We conclude that PACIA detects mycobacterial growth earlier than BACTEC and that M. tuberculosis can be distinguished from other mycobacteria in PACIA performed with specific monoclonal antibodies.

Antibodies, Monoclonal↗