Mycobacterial Heat Shock Protein Research Articles

Identification of individual DNA molecule of Mycobacterium tuberculosis by nested PCR-RFLP and capillary electrophoresis

The improvement of sensitivity and differentiation in rapidly identifying a small amount of mycobacteria in sputum has significant implications for reducing tuberculosis transmission. We previously applied the conventional PCR and capillary electrophoresis (CE) to establish the restriction fragment length polymorphism (RFLP) pattern of mycobacterial 65-kDa heat shock protein ( hsp65) gene from colony specimens. However, the previous analysis did not provide enough sensitivity for sputum specimens in which the limitation of analysis might be hindered by PCR inhibitors and primer-dimers formation during amplification. In the current study, nested PCR (nPCR) had been redesigned for PCR-RFLP analysis (PRA) of mycobacterial hsp65 gene using CE. The results show both Mycobacterium tuberculosis complex and mycobacteria other than tuberculosis could be identified in the presence of PCR inhibitors. The interference due to primer-dimers was also minimized. Based on the Poisson distribution, the repeatability of single DNA molecule detection was greatly affected by sampling probability and might be improved significantly by increasing the sample loading. The PRA using nPCR and CE is not only able to detect the individual mycobacterial DNA molecule but also potentially differentiate the species.

Phase I trial of DNA-hsp65 immunotherapy for advanced squamous cell carcinoma of the head and neck

Considering that mycobacterial heat-shock protein 65 (hsp65) gene transfer can elicit a profound antitumoral effect, this study aimed to establish the safety, maximum-tolerated dose (MTD) and preliminary efficacy of DNA-hsp65 immunotherapy in patients with advanced head and neck squamous cell carcinoma (HNSCC). For this purpose, 21 patients with unresectable and recurrent HNSCC were studied. Each patient received three ultrasound-guided injections at 21-day intervals of: 150, 600 or 400 microg of DNA-hsp65. Toxicity was graded according to CTCAE directions. Tumor volume was measured before and after treatment using computed tomography scan. The evaluation included tumor mass variation, delayed-type hypersensitivity response and spontaneous peripheral blood mononuclear cell proliferation before and after treatment. The MTD was 400 microg per dose. DNA-hsp65 immunotherapy was well tolerated with moderate pain, edema and infections as the most frequent adverse effects. None of the patients showed clinical or laboratory alterations compatible with autoimmune reactions. Partial response was observed in 4 out of 14 patients who completed treatment, 2 of which are still alive more than 3 years after the completion of the trial. Therefore, DNA-hsp65 immunotherapy is a feasible and safe approach at the dose of 400 microg per injection in patients with HNSCC refractory to standard treatment. Further studies in a larger number of patients are needed to confirm the efficacy of this novel strategy.

Real-time Quantitative PCR in the Diagnosis of Tuberculosis in Formalin-fixed Paraffin-embedded Pleural Tissue in Patients From a High HIV Endemic Area

The aim of the study was to improve the diagnosis of pleural tuberculosis (TB) based on formalin-fixed biopsies from patients living in high TB and human immunodeficiency virus (HIV) endemic areas. A real-time polymerase chain reaction (real-time PCR) assay targeting a segment of the gene for mycobacterial 65-kd heat shock protein was developed and evaluated on pleural biopsies from 25 patients clinically diagnosed as having TB, on the basis of the good response to treatment, and from 11 controls. A nested polymerase chain reaction (N-PCR) assay for the repetitive genetic sequence insert IS6110, common to Mycobacterium tuberculosis complex organisms, was performed for comparison. When compared with N-PCR, the real-time PCR assay gave a sensitivity and specificity of 83% and 72%, respectively. When compared with clinical diagnosis, the sensitivity and specificity of real-time PCR (68% and 73%, respectively) was comparable with the sensitivity and specificity of the N-PCR assay (64% and 82%, respectively). There were no major differences in the diagnostic validity for the confirmed TB/HIV coinfected patients compared with the results from the whole TB group. In conclusion, the overall accuracy of the real-time PCR assay was comparable with that of the N-PCR and both were equally useful as diagnostic tools in the setting of a HIV coinfection. The real-time PCR has the additional advantage of a short turn-around time, low risk of sample contamination, and offers the possibility to quantify bacterial load, making it a powerful tool for the rapid diagnosis of TB pleuritis.

Enhanced Immunogenicity of Peptide P277 by Heat Shock Protein HSP65 Vector Carrying Tandem Repeats of P277 to Prevent Type 1 Diabetes in NOD Mice

The peptide P277 contains a target epitope for diabetogenic T cells and it has been used as an ideal target antigen to develop vaccines against type 1 diabetes. A major problem in developing P277 vaccine is its low immunogenicity. Recent applications involving multiple copies of self-peptide in linear alignment and conjugation with carrier proteins appear to increase the immune response. In this study, we designed a method based on isocaudamer technique to repeat tandemly the 24-residue sequence P277, then 6 tandemly repeated copies of the peptide P277 were fused to mycobacterial heat-shock protein 65 to construct a fusion protein HSP65-6xP277 as an immunogen. We examined the effect of the tandem repeats of the peptide P277 in eliciting an immune response by comparing the immunogenicity of the three immunogens: P277, HSP65-P277 and HSP65-6xP277. Immunization of mice with the fusion protein HSP65-6xP277 elicited much higher levels of specific anti-P277 antibodies than with P277 and HSP65-P277, which should suggest that multiple tandem repeats of a certain epitope is an efficient method to overcome the low immunogenicity of self-peptide antigens and the immunogen HSP65-6xP277 might be further developed to a vaccine against type 1 diabetes.

Regulation of autoimmune arthritis by the pro-inflammatory cytokine interferon-γ

The pathogenesis of T cell-mediated diseases like rheumatoid arthritis (RA) has typically been explained in the context of the Th1–Th2 paradigm: the initiation/propagation by pro-inflammatory cytokines, and downregulation by Th2 cytokines. However, in our study based on the adjuvant-induced arthritis (AA) model of RA, we observed that Lewis (LEW) (RT.1 l) rats at the recovery phase of AA showed the highest level of IFN-γ in recall response to mycobacterial heat-shock protein 65 (Bhsp65), whereas AA-resistant Wistar-Kyoto (WKY) (RT.1 l) rats secreted high levels of IFN-γ much earlier following disease induction. However, no significant secretion of IL-10 or TGF-β was observed in either strain. Furthermore, pre-treatment of LEW rats with a peptide of self (rat) hsp65 (R465), which induced T cells secreting predominantly IFN-γ, afforded protection against AA and decreased IL-17 expression by the arthritogenic epitope-restimulated T cells. These results provide a novel perspective on the pathogenesis of autoimmune arthritis.

新しい結核ワクチンの開発

We have developed a novel tuberculosis (TB) vaccine ; a combination of the DNA vaccines expressing mycobacterial heat shock protein 65 (HSP65) and interleukin 12 (IL-12) delivered by the hemagglutinating virus of Japan (HVJ)-liposome or-envelope (HSP65+IL-12/HVJ). This vaccine provided remarkable protective efficacy in mouse and guinea pig models compared to the BCG vaccine, on the basis of an induction of the CD8 positive CTL activity against TB antigens and improvement of the histopathological tuberculosis lesions, respectively. The Elispot assay showed that HSP65+IL-12 DNA/ HVJ vaccine induced a greater number of IFN-gamma producing T cells than BCG in the mouse model. Furthermore, we extended our studies to a cynomolgus monkey model, which is currently the best animal model of human tuberculosis. This novel vaccine provided a higher level of the protective efficacy than BCG based upon the assessment of mortality, the ESR, body weight, chest X-ray findings and immune responses (IFN-gamma, IL-2, IL-6 production , and lymphocyte proliferation of cynomolgus monkey). The combination of HSP65+IL-12/HVJ and BCG by the priming-booster method showed a synergistic effect in the TB-infected cynomolgus monkey (100% survival). In contrast, 33% of monkeys from BCG Tokyo alone group were alive (33% survival). These data indicate that our novel DNA vaccine might be useful against Mycobacterium tuberculosis for human clinical trials.

Mycobacterial Heat Shock Proteins as Vaccines - A Model of Facilitated Antigen Presentation

Heat shock proteins (hsps) are a highly conserved family of proteins, first recognized by their upregulated expression in response to host exposure to raised temperatures. Further study has revealed that they have numerous functions in the cell, primarily as chaperones mediating both the correct folding of nascent polypeptide chains and the dissolution of aggregated protein complexes. The energy requirement for this chaperone activity is provided by the ATPase activity found in most families of hsps and thus the peptide binding capacity is controlled by ATP hydrolysis. The structural consequence of this is that hsps isolated in situ are found complexed to chaperoned peptides (hspCs). Much previous work has implicated hsps in the immune response to pathogens and recent studies have shown that the interaction of hsps with antigen presenting cells, such as dendritic cells (DCs), mediates the integration of the innate and acquired immune responses. This central role for hspCs in immunity is facilitated by their dual function in both innate immunity, with the induction of cytokines and the maturation of DCs mediated by the hsp component, and acquired immunity, with the trafficking of antigens chaperoned in hspCs for antigen presentation by the mature DCs.

Novel vaccination (HVJ-liposome/HSP65 DNA+ IL-12 DNA against Tuberculosis) (47.15)

Abstract We have developed a novel tuberculosis (TB) vaccine; a combination of the DNA vaccines expressing mycobacterial heat shock protein 65 (HSP65) and interleukin 12 (IL-12) delivered by the hemagglutinating virus of Japan (HVJ)-liposome (HSP65+IL-12/HVJ). This vaccine provided remarkable protective efficacy in BALB/C mouse and guinea pig models compared to the BCG vaccine, on the basis of an induction of the CTL activity and improvement of the histopathological tuberculosis lesions, respetively. This vaccine strongly induced CTL against HSP antigen and M.tuberculosis antigens Furthermore, we extended our studies to a cynomolgus monkey model, which is currently the best animal model of human tuberculosis. This novel vaccine provided a higher level of the protective efficacy than BCG based upon the assessment of mortality, the ESR and immune responses. The combination of HSP65 + IL-12/HVJ and BCG by the priming-booster method showed a synergistic effect in the TB-infected cynomolgus monkey (100% survival). In contrast, the survival of the BCG Tokyo group was 33%. These data indicate that our novel DNA vaccine might be useful against M.tuberculosis for human clinical trials. [H-17-Shinko-5] of Research on Emerging and Re-emerging Infectious Diseases in Health Sciences Research grants from Japan.

Protection against autoimmune arthritis induced by hsp65-mediated tolerance involves enhanced production of both IFN-γ and antigen-specific antibodies (128.23)

Abstract Induction of antigen-specific immune tolerance is a desired goal of many therapeutic approaches against autoimmune diseases. Adjuvant arthritis (AA), an animal model of human rheumatoid arthritis (RA), is a Th1-mediated disease and it can be induced in Lewis (LEW) (RT.1l) rats by s.c. injection of heat-killed M. tuberculosis. Arthritic LEW rats raise T cell and antibody responses to mycobacterial heat shock protein 65 (Bhsp65). We employed a novel tolerogenic approach by introducing a Bhsp65-IgG heavy chain gene construct retrovirally ex vivo into B cells and then injecting these cells i.p. into syngeneic recipients. In another approach, we injected LEW rats i.p. with soluble Bhsp65. The former approach was successful in preventing as well as treating ongoing AA, whereas the latter was effective in the prevention. We observed significantly reduced T cell proliferative response to Bhsp65 in rats injected with either Bhsp65-IgG-expressing B cells or soluble Bhsp65 compared to the respective controls. This reduced T cell proliferation was restored by IL-2. Interestingly, there was increased production of IFN-γ by Bhsp65-primed cells in the Bhsp65-treated LEW rats, whereas not much change was observed in IL-10 secretion. The frequency of CD4+FoxP3+ T cells in peripheral blood did not change following tolerization. However, a high level of serum anti-Bhsp65 antibodies was observed in tolerized rats much earlier during the course of AA than that in controls. Regulation of a Th1-mediated autoimmune disease by a pro-inflammatory cytokine (IFN-γ) and the disease-protective attribute of antibodies represent novel aspects of this study. B cell-mediated suppression of established autoimmunity offers a promising approach for the treatment of RA. (Support: Arthritis Foundation and NIH)

Evaluation of a novel vaccine (HVJ–liposome/HSP65 DNA + IL-12 DNA) against tuberculosis using the cynomolgus monkey model of TB

We have developed a novel tuberculosis (TB) vaccine; a combination of the DNA vaccines expressing mycobacterial heat shock protein 65 (HSP65) and interleukin 12 (IL-12) delivered by the hemagglutinating virus of Japan (HVJ)-liposome (HSP65 + IL-12/HVJ). This vaccine provided remarkable protective efficacy in mouse and guinea pig models compared to the BCG vaccine, on the basis of an induction of the CTL activity and improvement of the histopathological tuberculosis lesions, respectively. Furthermore, we extended our studies to a cynomolgus monkey model, which is currently the best animal model of human tuberculosis. This novel vaccine provided a higher level of the protective efficacy than BCG based upon the assessment of mortality, the ESR, body weight, chest X-ray findings and immune responses. Furthermore, the combination of HSP65 + IL-12/HVJ and BCG by the priming-booster method showed a synergistic effect in the TB-infected cynomolgus monkey (100% survival). These data indicate that our novel DNA vaccine might be useful against Mycobacterium tuberculosis for human clinical trials.

Immunologic response enhances atherosclerosis—type 1 helper T cell (Th1)-to-type 2 helper T cell (Th2) shift and calcified atherosclerosis in Bacillus Calmette-Guerin (BCG)-treated apolipoprotein E-knockout (apo E −/−) mice

Although immunocompetent hosts develop protective type 1 helper T cell (Th1) responses in mycobacterial infections, seroepidemiologic studies show that patients with atherosclerosis commonly express high antibody titers against mycobacterial heat shock protein (HSP) 65 and may develop a nonprotective type 2 helper T cell (Th2) response and advanced disease. These studies were undertaken to define mycobacterial dose requirements and kinetics for development of antibodies to HSP65, the Th1 to Th2 shift of immune response, and calcified atherosclerotic lesion development in the apo E-/- mouse. Fourteen-week apo E-/- female mice were treated intraperitoneally (ip) with heat-killed M. bovis Bacillus Calmette-Guerin (BCG), and 14 days later, cross-sections from the ascending aortas were stained for measurement of lesion size and calcium deposition. At 14 days, 0.01-mg BCG induced Th1 responses against HSP65. In contrast, 1-mg BCG induced splenic PGE2-releasing macrophages with a Th1-to-Th2 shift of responses to HSP65, which was PGE2-dependent. Treatment with 1-mg BCG significantly lowered bone density with increases in marrow osteoclastogenesis and development of calcified lesions in the aorta. At 14 days, 0.01-mg BCG induced Th1-dependent HSP65 responses and did not advance atherosclerosis. In contrast, for 1-mg BCG, a PGE2-dependent Th1-to-Th2 shift of responses to HSP65 and evidence of bone resorption are associated with advanced calcified atherosclerotic lesions.

Celastrus aculeatus Merr. suppresses the induction and progression of autoimmune arthritis by modulating immune response to heat-shock protein 65

Complementary and alternative medicine products are increasingly being used for the treatment of autoimmune diseases. However, the mechanisms of action of these agents are not fully defined. Using the rat adjuvant arthritis (AA) model of human rheumatoid arthritis, we determined whether the ethanol extract of Celastrus aculeatus Merr. (Celastrus), a Chinese herb, can down-modulate the severity of AA, and also examined the Celastrus-induced changes in immune responses to the disease-related antigen mycobacterial heat-shock protein 65 (Bhsp65). AA was induced in the Lewis (LEW; RT.1l) rat by immunization subcutaneously with heat-killed M. tuberculosis H37Ra (Mtb). Celastrus was fed to LEW rats by gavage daily, beginning either before Mtb challenge (preventive regimen) or after the onset of AA (therapeutic regimen). An additional group of rats was given methotrexate for comparison. All rats were graded regularly for the signs of arthritis. In parallel, the draining lymph node cells of Celastrus-treated rats were tested for proliferative and cytokine responses, whereas their sera were tested for the inflammatory mediator nitric oxide. Celastrus feeding suppressed both the induction as well as the progression of AA, and the latter effect was comparable to that of methotrexate. Celastrus treatment induced relative deviation of the cytokine response to anti-inflammatory type and enhanced the production of anti-Bhsp65 antibodies, which are known to be protective against AA. Celastrus feeding also reduced the levels of nitric oxide. On the basis of our results, we suggest further systematic exploration of Celastrus as an adjunct therapeutic modality for rheumatoid arthritis.

Resolution of inflammatory acne vulgaris may involve regulation of CD4+ T-cell responses to Propionibacterium acnes

Propionibacterium acnes has been strongly implicated in inflammatory acne. However, its role in the disease is unclear. It has been hypothesized that an immune response to P. acnes and/or P. acnes heat shock proteins (HSPs) may play a role in the pathogenesis of inflammatory acne. To compare the cell-mediated immune response to P. acnes and HSPs in acne patients, nonacne controls and individuals with resolved acne. The proliferative response of peripheral blood mononuclear cells (PBMC) from acne patients, resolved acne donors and healthy controls to P. acnes, P. acnes HSP60 and HSP70, and mycobacterial HSPs was assessed by lymphocyte transformation assay (LTA). The proliferative response of purified CD4+ T cells was further analysed by limiting dilution analysis (LDA). Contingency tables (G-test) were used to analyse the proportion of individuals in each group showing a positive proliferative response for LTA or data fitting single-hit kinetics for LDA. Analysis of stimulation of PBMC with P. acnes, P. acnes HSP60 and HSP70 in the LTA showed the proportion of positive responders to be independent of subject group. However, the proportion of acne patients with a positive response to mycobacterial HSPs was significantly higher than those for the other subject groups. Analysis of LDA data showed the proportion of resolved donors with responses to P. acnes fitting the single-hit kinetics model to be significantly lower than those of the other groups. There were no significant differences in responses to other antigens. The significantly lower proportion of resolved donors demonstrating a single-hit kinetics response to P. acnes by LDA may represent negative regulation of the CD4+ T-cell response to P. acnes in these subjects.

Antibody Responses to Mycobacterial and Self Heat Shock Protein 65 in Autoimmune Arthritis: Epitope Specificity and Implication in Pathogenesis

Many autoimmune diseases are believed to involve primarily T cell-mediated effector mechanisms. There is increasing realization, however, that Abs may also play a vital role in the propagation of T cell-driven disorders. In this study, on the rat adjuvant-induced arthritis (AA) model of human rheumatoid arthritis, we examined the characteristics of serum Ab response to mycobacterial heat shock protein (hsp) 65 (Bhsp65), self (rat) hsp65 (Rhsp65), and linear peptides spanning these two molecules. The AA-resistant WKY (RT.1(l)) rat responded to the heat-killed Mycobacterium tuberculosis immunization with a rapid burst of Abs to both Bhsp65 and Rhsp65. These Abs reacted with numerous peptide epitopes; however, this response was reduced to a few epitopes with time. On the contrary, the susceptible Lewis (RT.1(l)) rat developed a relatively lower Ab response to Bhsp65, and Abs to Rhsp65 did not appear until the recovery from the disease. The Ab response in Lewis rats diversified with progression of AA, and there was an intriguing overlap between the repertoire of Bhsp65-reactive B and T cells during the recovery phase of AA. Nonetheless, subsets of the repertoire of the late Abs in both rat strains became focused on the same epitope regions of Bhsp65 and Rhsp65. The functional relevance of these Abs was evident from the results showing that sera from recovery phase Lewis or WKY rats, but not that of naive rats, afforded protection against subsequent AA. These results are of significance in further understanding of the role of humoral immunity in the pathogenesis of autoimmune arthritis.

Dendritic Cell Stimulation by Mycobacterial Hsp70 Is Mediated Through CCR5

An effective host immune response to mycobacterial infection must control pathogen dissemination without inducing immunopathology. Constitutive overexpression of mycobacterial heat shock protein (myHsp70) is associated with impaired bacterial persistence, but the immune-mediated mechanisms are unknown. We found that myHsp70, in addition to enhancing antigen delivery to human dendritic cells, signaled through the CCR5 chemokine receptor, promoting dendritic cell aggregation, immune synapse formation between dendritic cells and T cells, and the generation of effector immune responses. Thus, CCR5 acts as a pattern-recognition receptor for myHsp70, which may have implications for both the pathophysiology of tuberculosis and the use of myHsps in tumor-directed immunotherapy.

Immune Response Regulation

Mycobacterial heat shock proteins have been implicated in the way the host response to mycobacterial infection is finely balanced to control pathogen dissemination while preventing immunopathology. Constitutive overexpression of mycobacterial Hsp70 (myHsp70) enhances mycobacterial clearance in mouse models, and Hsps can promote antitumor and antiviral immune responses. Human dendritic cells pulsed with myHsp70 generate potent antigen-specific cytotoxic T cell responses, which are dependent on a calcium-signaling cascade. Floto et al . now show that this critical function of myHsp70 is dependent on signaling through the HIV coreceptor, CCR5. R. A. Floto, P. A. MacAry, J. M. Boname, T. S. Mien, B. Kampmann, J. R. Hair, O. S. Huey, E. N. G. Houben, J. Pieters, C. Day, W. Oehlmann, M. Singh, K. G. C. Smith, P. J. Lehner, Dendritic cell stimulation by mycobacterial Hsp70 is mediated through CCR5. Science 314 , 454-458 (2006). [Abstract] [Full Text]

Mycobacterium tuberculosis Complex and Mycobacterial Heat Shock Proteins in Lymph Node Tissue from Patients with Pulmonary Sarcoidosis

We demonstrated that not whole Mycobacterium tuberculosis but its particular antigens, hsp70(Mtb), hsp65(Mtb), and hsp16(Mtb), are present in lymph node tissues of patients with sarcoidosis (SA). hsp16(Mtb) occurs in the early stage of SA, whereas hsp70(Mtb) occurs in stage II of SA. hsp65(Mtb) is highly expressed in the capillary vessels in lymph node tissues in patients with SA.

Cardiovascular disease could be contained based on currently available data!

Largely due to better control of infectious diseases and significant advances in biomedical research, life expectancy worldwide has increased dramatically in the last three decades. However, as the average age of the population has risen, the incidence of chronic age-related diseases such as arthritis, Alzheimer's, Parkinson's, cardiovascular disease, cancer, osteoporosis, benign prostatic hyperplasia, and late-onset diabetes have increased and have become serious public health problem, as well. The etiology of these disorders is still incompletely understood, therefore, neither preventive strategies nor long-term effective treatment modalities are available for these disorders. In keeping with the aforementioned, the ultimate goal in cardiovascular research is to prevent the onset of cardiovascular episodes and thereby allow successful ageing without morbidity and cognitive decline. Herein, I argue that cardiovascular episodes could be contained with relatively simple approaches. Cardiovascular disorder is characterized by cellular and molecular changes that are commonplace in age-related diseases in other organ system, such alterations include increased level of oxidative stress, perturbed energy metabolism, and "horror autotoxicus" largely brought about by the perturbation of ubiquitin -proteasome system, and excessive oxidative stress damage to the cardiac muscle cells and tissues, and cross-reactions of specific antibodies against human heat shock protein 60 with that of mycobacterial heat shock protein 65. "Horror autotoxicus", a Latin expression, is a term coined by Paul Ehrlich at the turn of the last century to describe autoimmunity to self, or the attack of "self" by immune system, which ultimately results to autoimmune condition. Based on the currently available data, the risk of cardiovascular episodes and several other age-related disorders, including cancer, Alzheimer's disease and diabetes, is known to be influenced by the nature and level of food intake. Now, a wealth of scientific data from studies of rodents and monkeys has documented the significant beneficial effects of calorie restriction (CR) or dietary restriction (DR), and multiple antioxidant agents in extending life span and reducing the incidence of progeroid-related diseases. Reduced levels of cellular oxidative stress, protection of genome from deleterious damage, detoxification of toxic molecules, and enhancement of energy homeostasis, contribute to the beneficial effects of dietary restriction and multiple antioxidant agents. Recent findings suggest that employment of DR and multiple antioxidant agents (including, catalase, glutathione peroxidase, CuZn superoxide dismutase, and Mn superoxide dismutase = enzymes forming the primary defense against oxygen toxicity), and ozone therapy may mount an effective resistance to pathogenic factors relevant to the pathogenesis of cardiovascular episodes. Hence, while further studies will be needed to establish the extent to which CR and multiple antioxidant agents will reduce incidence of cardiovascular episodes in humans, it would seem prudent to recommend CR and multiple antioxidant agents as widely applicable preventive approach for cardiovascular disorders and other progeroid-related disorders.

Oxidized Low-Density Lipoprotein Autoantibodies, Chronic Infections, and Carotid Atherosclerosis in a Population-Based Study

We investigated whether associations exist between immune reactions to oxidized low-density lipoproteins (OxLDLs), chronic infections, and carotid atherosclerosis as quantified by ultrasound. Atherosclerosis is a chronic immuno-inflammatory disease wherein both oxidized lipids and infectious agents are incriminated as possible contributors. We measured immunoglobulin (Ig)G and IgM autoantibody titers to copper-oxidized-LDL and malondialdehyde-LDL (OxLDL-AB), IgG and IgM apolipoprotein B-100-immune complexes (ApoB-IC), and titers of antibodies to Escherichia coli and chlamydial lipopolysaccharide (LPS), mycobacterial heat shock protein 65 (mHSP65), Chlamydia pneumoniae, Helicobacter pylori, and cytomegalovirus and evaluated their relationship to cardiovascular risk factors, chronic infections, and incident/progressive carotid atherosclerosis in the Bruneck study. The OxLDL-AB and ApoB-IC levels remained stable over time as indicated by strong correlations between 1995 and 2000 measurements (p < 0.001 each). Significant associations existed between all OxLDL markers and antibody titers to pathogens, especially to E. coli-LPS and mHSP65. Both OxLDL-AB and ApoB-IC levels showed a rise with increasing pathogen burden. Notably, OxLDL-ABs were also elevated in subjects with chronic infection as defined by clinical criteria. Titers of IgG, but not IgM, OxLDL-AB, or ApoB-IC inversely correlated with total cholesterol, LDL cholesterol, and apoB concentrations. The IgG OxLDL markers were positively and IgM markers were inversely associated with incident and progressive carotid atherosclerosis in univariate analyses but were not independent predictors in multivariate analyses. Our study provides evidence for an association between human oxLDL markers and chronic infections. Moreover, in this population-based study, neither IgG nor IgM OxLDL autoantibodies were independently predictive of atherosclerosis progression in the carotid arteries.

Ten tandem repeats of β-hCG 109–118 enhance immunogenicity and anti-tumor effects of β-hCG C-terminal peptide carried by mycobacterial heat-shock protein HSP65

The β-subunit of human chorionic gonadotropin (β-hCG) is secreted by many kinds of tumors and it has been used as an ideal target antigen to develop vaccines against tumors. In view of the low immunogenicity of this self-peptide,we designed a method based on isocaudamer technique to repeat tandemly the 10-residue sequence X of β-hCG (109–118), then 10 tandemly repeated copies of the 10-residue sequence combined with β-hCG C-terminal 37 peptides were fused to mycobacterial heat-shock protein 65 to construct a fusion protein HSP65-X10-βhCGCTP37 as an immunogen. In this study, we examined the effect of the tandem repeats of this 10-residue sequence in eliciting an immune by comparing the immunogenicity and anti-tumor effects of the two immunogens, HSP65-X10-βhCGCTP37 and HSP65-βhCGCTP37 (without the 10 tandem repeats). Immunization of mice with the fusion protein HSP65-X10-βhCGCTP37 elicited much higher levels of specific anti-β-hCG antibodies and more effectively inhibited the growth of Lewis lung carcinoma (LLC) in vivo than with HSP65-βhCGCTP37, which should suggest that HSP65-X10-βhCGCTP37 may be an effective protein vaccine for the treatment of β-hCG-dependent tumors and multiple tandem repeats of a certain epitope are an efficient method to overcome the low immunogenicity of self-peptide antigens.