Mycobacterial Heat Shock Protein Research Articles

Novel vaccines for the treatment of chronic HBV infection based on mycobacterial heat shock protein 70

Immunogenic peptide-based vaccines can raise significant cellular immune responses. Although cytotoxic T lymphocytes (CTL) peptide epitopes are generally poor immunogens, heat shock protein 70 from Mycobacterium tuberculosis (TBhsp70) can overcome this problem since it is a potent adjuvant that links innate and adaptive immune responses. Our goal is to use TBhsp70 as an adjuvant for development of therapeutic vaccines for chronic Hepatitis B virus infection (HBV). To this end, we genetically fused the HBV core 18–27 peptide (HBcAg (18–27)) as a CTL epitope to the C-terminus of TBhsp70 and expressed the resulting protein in methylotropic yeast Pichia pastoris GS115. At the same time, the TBhsp70-HBcAg (18–27) peptide complex was reconstituted in vitro. We investigated whether TBhsp70–peptide complex and TBhsp70–peptide fusion protein could generate antigen specific CTL responses in vitro. Dendritic cells (DC) from HLA-A2 + chronic HBV infection and healthy control pulsed with two vaccines were studied phenotypically by FACS analyses and functionally by cytokine release, and HBV-specific CTL response. Our results demonstrate that two vaccines can activate DC of chronic HBV infection and healthy control by upregulation CD40 and CD86, high production of IL-12p70 and TNF-α. Furthermore, autologous T cells with DC stimulated by two vaccines can produce IFN-γ and generate HBV-specific CTL response. However, capacity for CTL response and cytokines production from HBV infections remained inferior to that of healthy controls. Thus, the strategy of utilizing TBhsp70 may provide a novel design for the development of prophylactic and therapeutic vaccines.

Improved efficacy of DNA vaccination against breast cancer by boosting with the repeat beta-hCG C-terminal peptide carried by mycobacterial heat-shock protein HSP65

Studies have demonstrated that active-specific immunotherapy has potential for controlling mammary tumor progression. Human chorionic gonadotropin (hCG) is expressed and extremely sensitive, easily detectable and highly correlated with breast cancer. We developed a gene vaccine using a plasmid vector to deliver the six copies of 10-amino acid residues of β-hCG 109–118 and β hCG C-terminal 37-amino acid (CTP37). BALB/c female mice were immunized with a combination of pCR-HBc-X6-βhCGCTP37 DNA vaccine and HSP-X6-βhCGCTP37 protein vaccine. pCR-HBc-X6-βhCGCTP37 DNA vaccine were injected intramuscularly three times, on days −46,−25 and −11 and HSP-X6-βhCGCTP37 protein were applied two times, 21 and 14 days before tumor cell challenge. We assessed a combined DNA and protein vaccine for its effect of against murine EMT6 mammary tumor cells. In this study, animals vaccinated DNA vaccination boosting with the repeat β-hCG C-terminal peptide carried by mycobacterial heat-shock protein HSP65 induced higher avidity antibodies and effectively inhibited the growth of tumor, compared with treatment using DNA alone or BCG priming HSP-X6-βhCGCTP37 protein boosting. The data presented demonstrate that improve immunogenicity of DNA vaccination by boosting with the repeat β-hCG C-terminal peptide carried by mycobacterial heat-shock protein HSP65, which should prove useful in the development of new DNA vaccine against growth factors for cancer immunotherapy.

Mycobacterium tuberculosis complex in atherosclerosis.

In recent years, the results of some studies have revealed the possible potential role of several infectious agents in the inflammatory mechanism of atherosclerosis. The detection of specific antibodies against microorganisms such as and as well as Chlamydia pneumoniae and cytomegalovirus as well as antibodies directed to heat shock proteins in the sera of atherosclerotic patients and the presence of genomic material in atheromatous plaques all provide evidence supporting the presumptive role of infectious agents in atherosclerosis. There are some findings that can be accepted as clues for the possible involvement of Mycobacterium tuberculosis in atherosclerosis. These consist of the presence of high levels of mycobacterial heat shock protein 65 in atherosclerotic patients, and in animal studies, the detection of atherosclerotic changes in the vascular wall of animals vaccinated with recombinant heat shock protein 65, and Mycobacterium tuberculosis containing heat shock protein 65. The probable proatherogenic effect of the specific immune response to BCG-associated heat shock protein was also suggested. The mycobacterium cell wall contains a phospholipid, phosphatidylinositol, which was shown to have a procoagulant effect similar to that of a cytomegalovirus possessing phosphatidylserine, another phospholipid showing a procoagulant effect. These data suggest that Mycobacterium tuberculosis may also be involved in the pathogenesis of atherosclerosis.

Antagonists of Hsp16.3, a Low-Molecular-Weight Mycobacterial Chaperone and Virulence Factor, Derived from Phage-Displayed Peptide Libraries

The persistence of Mycobacterium tuberculosis is a major cause of concern in tuberculosis (TB) therapy. In the persistent mode the pathogen can resist drug therapy, allowing the possibility of reactivation of the disease. Several protein factors have been identified that contribute to persistence, one of them being the 16-kDa low-molecular-weight mycobacterial heat shock protein Hsp16.3, a homologue of the mammalian eye lens protein alpha-crystallin. It is believed that Hsp16.3 plays a key role in the persistence phase by protecting essential proteins from being irreversibly denatured. Because of the close association of Hsp16.3 with persistence, an attempt has been made to develop inhibitors against it. Random peptide libraries displayed on bacteriophage M13 were screened for Hsp16.3 binding. Two phage clones were identified that bind to the Hsp16.3 protein. The corresponding synthetic peptides, an 11-mer and a 16-mer, were able to bind Hsp16.3 and inhibit its chaperone activity in vitro in a dose-dependent manner. Little or no effect of these peptides was observed on alphaB-crystallin, a homologous protein that is a key component of human eye lens, indicating that there is an element of specificity in the observed inhibition. Two histidine residues appear to be common to the selected peptides. Nuclear magnetic resonance studies performed with the 11-mer peptide indicate that in this case these two histidines may be the crucial binding determinants. The peptide inhibitors of Hsp16.3 thus obtained could serve as the basis for developing potent drugs against persistent TB.

DNA vaccine using hemagglutinating virus of Japan-liposome encapsulating combination encoding mycobacterial heat shock protein 65 and interleukin-12 confers protection against Mycobacterium tuberculosis by T cell activation

We investigated the immunogenicity and protective efficacy of DNA vaccine combinations expressing mycobacterial heat shock protein 65 (Hsp65) and interleukin-12 (IL-12) using gene gun bombardment and the hemagglutinating virus of Japan (HVJ)-liposome method. A mouse IL-12 expression vector (mIL-12 DNA) encoding single-chain IL-12 proteins comprised of p40 and p35 subunits were constructed. In a mouse model, a single gene gun vaccination with the combination of Hsp65 DNA and mIL-12 DNA provided a remarkably high degree of protection against challenge with virulent Mycobacterium tuberculosis; bacterial numbers were 100-fold lower in the lungs compared to BCG-vaccinated mice. To explore the clinical use of the DNA vaccines, we evaluated HVJ-liposome encapsulated Hsp65 DNA and mIL-12DNA (Hsp65 + mIL-12/HVJ). The HVJ-liposome method improved the protective efficacy of the Hsp65 DNA vaccine compared to gene gun vaccination. Hsp65 + mIL-12/HVJ induced CD8 + cytotoxic T lymphocyte activity against Hsp65 antigen. Most importantly, Hsp65 + mIL-12/HVJ vaccination resulted in a greater degree of protection than that evoked by BCG. This protective efficacy was associated with the emergence of IFN-γ-secreting T cells and activation of proliferative T cells and cytokines (IFN-γ and IL-2) production upon stimulation with Hsp65 and antigens from M. tuberculosis. These results suggest that Hsp65 + IL-12/HVJ could be a promising candidate for a new tuberculosis DNA vaccine, which is superior to BCG vaccine.

Mycobacterium Tuberculosis Heat Shock Proteins Use Diverse Toll-like Receptor Pathways to Activate Pro-inflammatory Signals

Although the Toll-like receptors used by Mycobacterium tuberculosis membrane and secreted factors are known, the pathways activated by M. tuberculosis heat shock proteins are not. An efficient immune response against the intracellular pathogen M. tuberculosis is critically dependent on rapid detection of the invading pathogen by the innate immune system and coordinated activation of the adaptive immune response. Macrophage phagocytosis of M. tuberculosis is accompanied by activation of the transcription factor NF-kappaB and secretion of inflammatory mediators that play an important role in granuloma formation and immune protection during M. tuberculosis infection. The interaction between M. tuberculosis and the various Toll-like receptors is complex, and it appears that distinct mycobacterial components may interact with different members of the Toll-like receptor family. Here we show that recombinant, purified, mycobacterial heat shock proteins 65 and 70 induce NF-kappaB activity in a dose-dependent manner in human endothelial cells. Furthermore, we show that whereas mycobacterial heat shock protein 65 signals exclusively through Toll-like receptor 4, heat shock protein 70 also signals through Toll-like receptor 2. Mycobacterial heat shock protein 65-induced NF-kappaB activation was MyD88-, TIRAP-, TRIF-, and TRAM-dependent and required the presence of MD-2. A better understanding of the recognition of mycobacterial heat shock proteins and their role in the host immune response to the pathogen may open the way to a better understanding of the immunological processes induced by this important human pathogen and the host-pathogen interactions and may help in the rational design of more effective vaccines or vaccine adjuvants.

Vaccinating Rabbits with a Cholesteryl Ester Transfer Protein (CETP) B-Cell Epitope Carried by Heat Shock Protein-65 (HSP65) for Inducing Anti-CETP Antibodies and Reducing Aortic Lesions In Vivo

Rabbits were vaccinated with a recombinant protein vaccine of HSP65-CETPC comprising mycobacterial heat shock protein-65 (HSP65) and a cholesteryl ester transfer protein (CETP) B-cell epitope in alum adjuvant for inducing anti-CETP antibodies in vivo. After anti-CETP antibodies were successfully produced, rabbits were fed with a high-cholesterol diet for 15 weeks, and then the antiatherogenic effects of anti-CETP antibodies were evaluated. The results showed that the fraction of plasma cholesterol in HDL increased and the fraction of plasma cholesterol in LDL decreased in rHSP65-CETPC-immunized rabbits when compared with those in control animals. The average percentage of aortic lesions in the entire aorta area in rHSP65-CETPC-vaccinated rabbits was 23.8% less than in OVA-immunized rabbits (15.14% vs 19.86%) and 30.8% less than in rHSP65 immunized rabbits (15.14% vs 21.87%). The average thickness of hyperplastic coronary artery in rHSP65-CETPC immunized rabbits was 164 +/- 12 microm, significantly lower than in rHSP65-immunized rabbits (197 +/- 15 microm) and in OVA-immunized rabbits (206 +/- 15 microm). Taken together, vaccination with the rHSP65-CETPC vaccine could significantly attenuate atherosclerosis in a rabbit model. Thus, the chimeric protein of rHSP65-CETPC can be further developed into an antiatherosclerosis vaccine in the future.

CD4+ T Cell-Mediated Antigen-Specific Immunotherapy in a Mouse Model of Cervical Cancer

A major agenda for tumor immunology is the generation of specific immune responses leading to the destruction of incipient and frank neoplasia. In this report, we show that a novel HPV16 E7 fusion protein can produce objective therapeutic responses against incipient cervical cancer in genetically engineered mice that express in the cervix the HPV16 early region genes implicated as causative agents in human cervical cancer. Although nonresponsive toward the HPV16 E7 oncoprotein in the CD8+ T-cell compartment by virtue of MHC haplotype, the mice were capable of mounting an induced CD4+ T-cell response against E7, and in addition developed spontaneous anti-E7 antibodies. HPV16/CD4-/- mice showed increased tumor burden indicative of CD4-mediated immune surveillance. Seeking to enhance the CD4 response, we immunized mice bearing incipient cervical cancer with a recombinant protein fusing E7 with a mycobacterial heat shock protein. The incidences of cervical carcinoma and of high-grade dysplasia (CIN 3) were consequently reduced by comparison to control mice. Thus, an HPV16 E7 immunogen holds promise for noninvasive treatment and prevention of human cervical cancer.

Novel recombinant BCG and DNA-vaccination against tuberculosis in a cynomolgus monkey model

We have developed two novel tuberculosis (TB) vaccines: a DNA vaccine combination expressing mycobacterial heat shock protein 65 (Hsp65) and interleukin-12 (IL-12) by using the hemagglutinating virus of Japan (HVJ)-liposome (HSP65 + IL-12/HVJ) and a recombinant BCG harboring the 72f fusion gene (72f rBCG). These vaccines provide remarkable protective efficacy in mouse and guinea pig models, as compared to the current by available BCG vaccine. In the present study, we extended our studies to a cynomolgus monkey model, which is currently the best animal model of human tuberculosis, to evaluate the HSP65 + IL-12/HVJ and 72f rBCG vaccines. Vaccination with HSP65 + IL-12/HVJ as well as 72f rBCG vaccines provided better protective efficacy as assessed by the Erythrocyte Sedimentation Rate, chest X-ray findings and immune responses than BCG. Most importantly, HSP65 + IL-12/HVJ resulted in an increased survival for over a year. This is the first report of successful DNA vaccination and recombinant BCG vaccination against M. tuberculosis in the monkey model.

CD134 as target for specific drug delivery to auto-aggressive CD4+ T cells in adjuvant arthritis

T cells have an important role during the development of autoimmune diseases. In adjuvant arthritis, a model for rheumatoid arthritis, we found that the percentage of CD4+ T cells expressing the activation marker CD134 (OX40 antigen) was elevated before disease onset. Moreover, these CD134+ T cells showed a specific proliferative response to the disease-associated epitope of mycobacterial heat shock protein 60, indicating that this subset contains auto-aggressive T cells. We studied the usefulness of CD134 as a molecular target for immune intervention in arthritis by using liposomes coated with a CD134-directed monoclonal antibody as a drug targeting system. Injection of anti-CD134 liposomes subcutaneously in the hind paws of pre-arthritic rats resulted in targeting of the majority of CD4+CD134+ T cells in the popliteal lymph nodes. Furthermore, we showed that anti-CD134 liposomes bound to activated T cells were not internalized. However, drug delivery by these liposomes could be established by loading anti-CD134 liposomes with the dipalmitate-derivatized cytostatic agent 5'-fluorodeoxyuridine. These liposomes specifically inhibited the proliferation of activated CD134+ T cells in vitro, and treatment with anti-CD134 liposomes containing 5'-fluorodeoxyuridine resulted in the amelioration of adjuvant arthritis. Thus, CD134 can be used as a marker for auto-aggressive CD4+ T cells early in arthritis, and specific liposomal targeting of drugs to these cells via CD134 can be employed to downregulate disease development.

Cellular and humoral immune responses to mycobacterial heat shock protein-65 and its human homologue in Takayasu's arteritis

Expression of heat shock protein (HSP)-65 as well as infiltration of T-cells in arterial lesions and raised levels of circulating antibodies against mycobacterial HSP65 (mHSP65) led us to the concept that mHSP65 or its human homologue (hHSP60) might be involved in the etiopathogenesis of Takayasu's arteritis (TA). Therefore, we investigated mHSP65 and hHSP60 reactive peripheral blood T-cell subsets by BrdU incorporation assay and flow cytometry as well as investigating the different isotypes of anti-mHSP65 and hHSP60 antibodies by ELISA. Eighty-four percent (22/26) of the TA patients were observed to show T-cell proliferation to mHSP65 and hHSP60 whereas only 16% (3/18) healthy controls showed such proliferation (P <0.001). Both HSPs induced proliferation of exclusively CD4+ T-cells and not CD8+ T-cells. We also observed a significantly higher prevalence of only the IgG isotype reactive to mHSP65 and hHSP60 in TA as compared to HC (mHSP65: 92% TA versus 11% HC, P <0.0001 and hHSP60: 84% versus 22%, P <0.001). Our data show a significant correlation between mHSP65 and hHSP60 reactive T-cells (CD3+: r=0.901; CD4+: r=0.968) as well as anti-mHSP65 and anti-hHSP60 IgG antibodies (r=0.814) suggesting an infection induced autoimmunity in TA, possibly induced by molecular mimicry between mHSP65 and hHSP60 or other tissue specific antigens.

Low levels of antibodies against E. coli and mycobacterial 65kDa heat shock proteins in patients with inflammatory bowel disease

The aim of the present study was to support and extend our initial observation, where we found low levels of antibodies against mycobacterial 65kD heat shock proteins in patients with inflammatory bowel disease (IBD). For this purpose we tested a new group of 124 patients with IBD, and beside measuring antibodies to Mycobacterium bovis 65kD heat shock protein (Hsp65) and human 60kD heat shock protein (Hsp60) as described previously, we also determined IgG antibody levels to Hsp65 from E. coli, called GroEL. seventy-four patients with Crohn's disease (CD) (30 males, 44 females, 33 (27-45) years old, median (interquartile range)) and 50 patients with ulcerative colitis (UC) (22 males, 28 females, 38 (30-50) years old) were involved in the study. 110 healthy subjects (34 males, 76 females, 47 (37-53) years old) served as controls. Study subjects were consecutive patients referred to an IBD center for complex treatment of the disease. Methods and statistical analysis: The amounts of IgG-type antibodies reacting with proteins of the chaperonin 60 family were assessed by ELISA. Since the antibody levels to heat-shock proteins as variables were not normally distributed, non-parametric Mann-Whitney test and Dunn post hoc test were used for group comparisons. Median levels of anti-GroEL (7,5 (3,5-18,3)) and anti-Hsp65 (4,8 (2,1-7,85)) were significantly (GroEL p = 0,008; and Hsp65 p < 0,001) lower in the IBD patients than in the healthy subjects (GroEL: 10,0 (5,4-31,0); Hsp65: 7,04 (4,66-12,77)). However this difference was found to be restricted to the CD patients (GroEL: 7,5 (3,7-14,2); p < 0,05; Hsp65: 4,35 (1,90-6,94); p < 0,001). We did not find difference in the concentration of anti-human Hsp60 IgG levels between patients (Hsp60: 45,5 (24,9-69,0)) and healthy controls (38,4 (21,6-69,4). Regarding the serum concentrations of each antibody tested there was no significant difference between the active and inactive stage of disease. Our present findings support conclusion of our previous work, antibody levels not only for Mycobacterium bovis hsp65 but for E. coli GroEl were found to be decreased as well. In contrast no changes in the concentrations of human anti-hsp60 antibodies were observed. These findings indicate that production of antibodies to 65 kDa bacterial heat shock proteins is selectively impaired in IBD.

Exacerbation of rheumatoid arthritis following Helicobacter pylori eradication: disruption of established oral tolerance against heat shock protein?

A 62-year-old Japanese woman with RA received an eradication therapy against Helicobacter pylori in November 1999. Eight weeks later, successful eradication was confirmed by negative results for rapid urease test, pathologic findings, and a fall in anti-H. pylori IgG antibody titer. During the course, parameters for RA activity were exacerbated: C-reactive protein 1.1-4.2 mg/dL, rheumatoid arthritis precipitation antigen 2560-5120 dils., erythrocyte sedimentation rate 52-123 mm/h, and complements CH50 50 to over 60 U/mL. Lansbury index increased from 70% to 105%. Two more weeks later, the patient noticed right shoulder pain. She also complained of bilateral gonalgia two months later, and physical examination revealed increased fluid in the knee joints. Prednisolone was required to control the disease activity. The results of this case suggested that RA patients might experience a deleterious effect on the disease activity following H. pylori eradication possibly through disruption of the established oral tolerance against stress protein such as mycobacterial heat shock protein 65.

É possível uma vacina gênica auxiliar no controle da tuberculose?

Vacinas de DNA, ainda em fase de experimentação e testes clínicos, podem se tornar uma importante ferramenta de combate a doenças infecciosas para as quais, até hoje, não existe prevenção segura e eficaz, como a tuberculose. Nos últimos anos vários estudos têm sido dedicados ao desenvolvimento de vacinas de DNA que codificam proteínas de micobactérias, entre as quais destacam-se as que codificam o antígeno 85 (Ag 85) e a proteína de choque térmico de 65 kDa (hsp65). Estes dois antígenos foram os mais estudados apresentando resultados bastante satisfatórios em ensaios pré-clínicos e com grande volume de dados registrados na literatura. Além de proteger contra infecção experimental por Mycobacterium tuberculosis virulenta, a vacina DNA-hsp65 também apresenta atividade terapêutica, ou seja, é capaz de curar os animais previamente infectados, inclusive aqueles com bacilos resistentes a múltiplas drogas. Esta vacina, hoje em avaliação clínica no Brasil também para o tratamento de câncer, é capaz de induzir a produção de citocinas de padrão Th1 tal como IFN- interferon-gama, associadas ao controle da doença. Além disso, a vacina de DNA-hsp65 é capaz de estimular clones de células CD8 citotóxicos e CD4 que podem ser caracterizados como células de memória sendo responsáveis por conferir imunidade duradoura contra a infecção. Quando utilizada na terapia da infecção, a vacina de DNA-hsp65 faz com que haja uma mudança no padrão de resposta imune, induzindo a secreção de citocinas de padrão Th1 criando um ambiente favorável à erradicação do bacilo. Os resultados demonstram ainda que a via de administração e a formulação na qual a vacina é administrada exerce fundamental influência no padrão e duração da resposta imune desencadeada. O conjunto de resultados hoje disponíveis mostra que uma vacina de DNA contra a tuberculose contribuirá de maneira significativa no controle desta doença.

The regulatory C-terminal determinants within mycobacterial heat shock protein 65 are cryptic and cross-reactive with the dominant self homologs: implications for the pathogenesis of autoimmune arthritis.

The 65-kDa mycobacterial heat shock protein (Bhsp65) has been invoked in the pathogenesis of both adjuvant arthritis (AA) in the Lewis rat (RT.1(l)) and human rheumatoid arthritis. Arthritic Lewis rats in the late phase of AA show diversification of the T cell response to Bhsp65 C-terminal determinants (BCTD), and pretreatment of naive Lewis rats with a mixture of peptides representing these neoepitopes affords protection against AA. However, the fine specificity and physiologic significance of the BCTD-directed T cell repertoire, and the role of homologous self (rat) hsp65 (Rhsp65), if any, in spreading of the T cell response to Bhsp65 have not yet been examined. We observed that T cells primed by peptides comprising BCTD can adoptively transfer protection against AA to the recipient Lewis rats. However, these T cells can be activated by preprocessed (peptide) form of BCTD, but not native Bhsp65, showing that BCTD are cryptic epitopes. The BCTD-reactive T cells can be activated by the naturally generated (dominant) C-terminal epitopes of both exogenous and endogenous Rhsp65 and vice versa. Furthermore, certain individual peptides constituting BCTD and their self homologs can also induce protection against AA. These results support a model for the diversification of T cell response to Bhsp65 during the course of AA involving up-regulation of the display of cryptic BCTD coupled with spontaneous induction of T cell response to the cross-reactive dominant C-terminal epitopes of Rhsp65. The identification of disease-regulating cryptic determinants in Ags implicated in arthritis provides a novel approach for immunotherapy of rheumatoid arthritis.

The T cells specific for the carboxyl-terminal determinants of self (rat) heat-shock protein 65 escape tolerance induction and are involved in regulation of autoimmune arthritis.

Immunization of Lewis rats with heat-killed Mycobacterium tuberculosis H37Ra leads to development of polyarthritis (adjuvant-induced arthritis; AA) that shares several features with human rheumatoid arthritis (RA). Immune response to the 65-kDa mycobacterial heat-shock protein (Bhsp65) is believed to be involved in induction of AA as well as in experimental modulation of this disease. However, the understanding of several critical aspects of the pathogenesis of AA in the Lewis rat has severely been hampered by the lack of information both regarding the level as well as epitope specificity of tolerance to the mammalian self (rat) homologue of Bhsp65, 65-kDa rat heat-shock protein (Rhsp65), and about the functional attributes of the T cell repertoire specific for this self protein. In this study, we established that tolerance to Rhsp65 in the Lewis rat is incomplete, and that the residual T cells primed upon challenge with this self hsp65 are disease regulating in nature. We also have defined the T cell epitopes in the C-terminal region within Rhsp65 that contribute predominantly to the immune reactivity as well as the AA-protective effect of this self protein. Furthermore, the T cells primed by peptides comprising these C-terminal determinants can be efficiently restimulated by the naturally generated epitopes from endogenous Rhsp65, suggesting that self hsp65 might also be involved in natural remission from acute AA. These novel first experimental insights into the self hsp65-directed regulatory T cell repertoire in AA would help develop better immunotherapeutic approaches for autoimmune arthritis.

Elevated antibody levels against Chlamydia pneumoniae, human HSP60 and mycobacterial HSP65 are independent risk factors in myocardial infarction and ischaemic heart disease

The relative significance of traditional risk factors, chronic infections and autoimmune processes in the development of acute myocardial infarction (AMI) has not been fully elucidated. We compared serum IgG antibody titres to various pathogens, i.e. Chlamydia pneumoniae (Cpn), cytomegalovirus (CMV) and herpes simplex virus type 1 (HSV-1), and to the potential autoantigens human heat shock protein 60 (hHSP60) and mycobacterial heat shock protein 65 (mHSP65), in serum samples obtained from patients 3–48 h after AMI ( n=40) or stable effort angina (SEA, n=43), and from controls ( n=46). The strongest association was observed between AMI and the elevated level of hHSP60 antibodies. The association between AMI and the level of Cpn antibodies was also significant. High levels of hHSP60 and Cpn antibodies represented independent risk factors for the development of AMI, but the simultaneous presence of high levels of antibodies to Cpn and hHSP60 suggested a joint effect on the relative risk of AMI (OR=12.0–21.1). The antibody titres to mHSP65 were higher in the SEA group than in the controls, and the simultaneous presence of high levels of Cpn and mHSP65 antibodies meant an increased risk among the SEA patients. The antibody titres to CMV or HSV-1 were similar in the three groups. In conclusion, these results demonstrate associations of AMI with high levels of anti-hHSP60 and anti-Cpn antibodies, and of SEA with the level of anti-mHSP65 antibodies, these being independent risk factors.

Mycobacterial heat shock protein 70 induces interleukin-10 production: immunomodulation of synovial cell cytokine profile and dendritic cell maturation.

Cytokines are key modulators of the immune responses that take place in the inflamed synovium of arthritis patients. Consequently, substances that can reverse the inflammatory profile of the inflamed joint are potential tools for clinical management of the disease. Mycobacterial heat shock protein 70 (MTBHSP70) has been found to protect rats from experimentally induced arthritis through the induction of interleukin (IL)-10-producing T cells. In this study, we have demonstrated that MTBHSP70 induces IL-10 production in synoviocytes from arthritis patients and peripheral blood monoculear cells (PBMCs) from both patients and healthy controls. IL-10 production was accompanied by a decrease in tumour necrosis factor (TNF)-alpha production by synovial cells. Separation studies showed that the target cells were mainly monocytes. Accordingly, we observed that MTBHSP70 delayed maturation of murine bone marrow-derived dendritic cells. Our results suggest that MTBHSP may act on antigen-presenting cells (APCs) to modulate the cytokine response in arthritis and support an anti-inflammatory role for this protein, suggesting that it may be of therapeutic use in the modulation of arthritis.

Association of Serum Antibodies to Heat-Shock Protein 65 With Coronary Calcification Levels

Previous studies demonstrated an association between antibodies to mycobacterial heat-shock protein 65 (mHSP65) and carotid artery thickening. We examined whether mHSP65 antibodies are associated with levels of coronary calcification that appear to reflect preclinical coronary artery disease (CAD). Serum specimens from 201 healthy asymptomatic subjects (52% male; mean age, 56.6 years) undergoing electron-beam computed tomographic imaging were used to measure levels of mHSP65 and human HSP60 antibodies and antibodies to several infectious pathogens. We found that 84% of the study subjects had anti-mHSP65 IgG antibodies. Mean titers of mHSP65 antibodies were higher (1:394 versus 1:267, P=0.012) in individuals with than in those without elevated levels of coronary calcium (calcium score > or =150). Increasing titers of mHSP65 antibodies were significantly associated, in a dose-response manner, with elevated levels of coronary calcification. Individuals with the highest titers of mHSP65 antibodies (> or =1:800) had an adjusted odds ratio (OR) of 14.3 for having elevated coronary calcium (P=0.004). Association of mHSP65 antibodies with elevated coronary calcification levels was independent of CAD risk factors after multivariate adjustment (P=0.037). Interestingly, mHSP65 antibody titers were correlated with Helicobacter pylori infection (P=0.004), which maintained significance after adjustment for CAD risk factors and seropositivities to other pathogens (adjusted OR, 3.1; 95% CI, 1.4 to 6.6). No association was found between antibodies to human HSP60 and levels of coronary calcification. Antibodies to mHSP65 are associated with elevated levels of coronary calcification and correlated with H pylori infection, suggesting that pathogen-triggered autoimmunity plays a role in early atherosclerosis.

Impairment of vascular function following BCG immunisation is associated with immune responses to HSP-60 in the cholesterol-fed rabbit

An immune response to heat shock protein (HSP)-60/65 has recently been implicated in atherogenesis. The aim of this study was to determine whether this effect may be mediated by impairment of endothelial function. Rabbits were injected with bacillus Calmette-Guerin (BCG) vaccine ( n=12) or saline ( n=12). A further injection of BCG or saline was administered after 2 weeks. After a further 2 weeks, animals were fed either a 0.25–1% cholesterol diet or a chow diet for 16 weeks. Blood cholesterol levels were maintained at 10–12 mmol/l by altering the dietary cholesterol content. Plasma levels of anti-mycobacterial antibodies rose following BCG immunisation, but anti-HSP antibodies developed only in the BCG-immunised, cholesterol-fed rabbits. Aortic endothelium from cholesterol-fed, but not chow-fed, rabbits stained positively for HSP-60, independently of the immunisation protocol. Endothelial function was impaired in the BCG immunised, cholesterol-fed rabbits as measured by acetylcholine-mediated relaxation of isolated non-atherosclerotic carotid artery rings ( P<0.05). This impairment was positively associated with the level of plasma anti-HSP-60 antibodies ( P<0.01). These results suggest that BCG immunisation impairs endothelial responses, at least in part, by immune responses against mycobacterial and vascular HSP.