Do heat shock proteins play a role in Graves' disease? Heat shock protein-specific T-cells from Graves' disease thyroids do not recognize thyroid epithelial cells

Thyroid-derived T-cells from patients with Graves' disease were analyzed for their reactivity to recombinant heat shock proteins (hsp) and autologous thyroid epithelial cells (TEC). Five of six uncloned T-cell lines responded to stimulation with recombinant mycobacterial 71-kilodalton (kDa) hsp and cross-reacted with the corresponding amoebial and human proteins. Only one line reacted with recombinant 65-kDa hsp. Thyroid-derived T-cell lines also showed a proliferative response to TEC, which could be increased in four of the lines, when hsp expression was induced in thyroid cells by heat stress before the initiation of coculture. Clonal specificity analysis of thyroid-derived T-cell clones, however, demonstrated that distinct T-cells were responsible for the recognition of recombinant hsp and TEC. None of the clones responsive to recombinant hsp recognized TEC, whereas TEC-responsive clones did not react with recombinant hsp. Interestingly, the response of the majority of TEC-reactive clones could be dramatically increased when heat-shocked TEC were used as stimulator cells. These results suggest that T-cells specific for hsp of the 70- or 60-kDa families do not recognize TEC in the autoimmune thyroid gland. Heat shock-inducible proteins may, however, still play a role in the autoimmune process by facilitating the presentation of thyroid-specific autoantigen(s) to autoreactive T-cells.

Immune recognition of human Hsp60 by Lyme disease patient sera

Members of the Hsp60 family of microbial heat shock proteins frequently serve as immunodominant antigens and immunological responses to these highly conserved proteins have been implicated in the pathology of a number of autoimmune diseases and inflammatory processes associated with microbial infection. In the present study, sera from patients with Lyme disease were examined by Western blot analysis for the presence of IgG against Borrelia burgdorferi antigens and for autoreactive IgG against recombinant human Hsp60 (huHsp60). These results were then compared to those obtained using sera from normal healthy controls, patients with a variety of acute non-spirochete infections, and patients with rheumatoid arthritis (RA). The results indicate a high incidence of autoreactive antibodies against huHsp60 in the sera of Lyme disease patients (67.9%) and patients with RA (75%). Positive reactivity was observed at lower rates in sera from healthy controls (25%) and sera from patients with acute non-spirochete infections (38%). Together the data suggest an association between the presence of autoreactive antibodies against huHsp60 and infection with B. burgdorferi. A similar association may exist between the presence of autoreactive antibodies against huHsp60 and RA.

Vaccinia virus infection induces a stress response that leads to association of Hsp70 with viral proteins

We studied the impact of vaccinia virus infection on stress protein gene expression in human cells and investigated the possibility that eukaryotic heat shock proteins interact with viral components during assembly. Infection of human monocyte-macrophages by vaccinia virus caused a dramatic decrease in levels of cellular mRNAs such as those encoding actin and tubulin. In contrast, infection did not cause a significant reduction in the levels of Hsp90 and Hsp60 mRNAs and led to substantially increased levels of Hsp70 mRNAs. The accumulation of these stress protein mRNAs was due both to increases in their transcription rate and to their stability relative to other cellular mRNAs. The relative levels of the heat shock proteins and the other cellular proteins reflected the relative levels of their mRNAs. These results indicate that stress protein gene expression is relatively refractory to the generally deleterious effects of vaccinia virus infection on host cell gene expression. The continued expression of some of these stress proteins may be beneficial to the virus; the observations that the levels of Hsp70 are greatest at the peak of viral gene expression and that a large fraction of cellular Hsp70 is associated with vaccinia virus proteins suggest that Hsp70 is involved in vaccinia virus assembly.

Disease association of antibodies to human and mycobacterial hsp70 and hsp60 stress proteins

Structural homology between microbial and human stress proteins has been postulated to be a basis for autoimmunization in chronic inflammatory diseases. Therefore, we estimated by ELISA titration the antibody levels to mycobacterial (M) and human (H) recombinant hsp70 and M-hsp65 heat-shock proteins in sera of patients with Crohn's disease (n = 29), ulcerative colitis (n = 20) and nontuberculous mycobacterial disease of the lungs (n = 20). Antibodies to H-hsp60, separated by two-dimensional gel electrophoresis, were tested in six sera of each group of patients. In Crohn's disease, antibody titres to the M-hsp65 antigen without detectable H-hsp60 binding were significantly elevated in 52% of the patients. In contrast titres to both M-hsp70 and H-hsp70 were demonstrable and correlated, but increased over control values only in four (14%) patients. The antibody pattern in ulcerative colitis was found to be quite different: anti-H-hsp60 binding was demonstrable in most patients, although anti-M-hsp65 titres were not elevated. Furthermore, 25% of patients had significantly elevated titres to M-hsp70, but not to H-hsp70. In non-tuberculous mycobacterial pulmonary disease, about 50% of patients had elevated titres to both hsp65 and hsp71 mycobacterial antigens but not to the corresponding human proteins; patients with Mycobacterium xenopi infection had the highest titres in this group. These results demonstrate the existence of distinct disease-associated patterns in the human antibody response to stress protein antigens. However, these data are not sufficient to imply sensitization with mycobacteria in patients with inflammatory bowel diseases, since certain epitopes of heat-shock proteins are shared by several bacterial genera.

Induction of human hsp60 expression in monocytic cell lines

Both bacterial and mammalian heat shock proteins (HSP) are recognized by some T cells, and hsp60 recognition has been implicated in rheumatoid arthritis. We have developed a model to study the induction of hsp60 in human monocytic cell lines. An anti-mycobacterial hsp65 mAb (ML30), cross-reacting with human hsp60 was used to screen 21 human tumor cell lines in Western blot analysis. All T cell and B cell lymphomas constitutively expressed hsp60 protein at moderate to high levels, while little or no hsp60 protein was detected in two monocytic leukemia lines. Moderate to high levels of hsp60 mRNA and protein could be induced in the THP-I monocytic leukemia cell line by heat shock, retinoic acid, interferon (IFN)-gamma or tumor necrosis factor (TNF)-alpha treatment, the highest levels obtained with a combination of IFN-gamma/TNF-alpha. This was also seen using two rabbit anti-hsp60 antisera directed against the N-terminal or C-terminal part of the human hsp60 protein. The determinants detected by the ML30 mAb or the two rabbit anti-hsp60 antisera were not cell surface expressed, as measured with immunofluorescence (FACS) analysis on control cultured or cytokine treated cell lines. This could be a useful model for studies related to the induction of hsp60 in human cells.

Frequency of D8/17 B lymphocyte alloantigen in north Indian patients with rheumatic heart disease

Ninety patients with rheumatic heart disease and 50 age- and sex-matched healthy human volunteers representing a North Indian population were typed for the B cell alloantigen D8/17 using a monoclonal antibody and a single step immunofluorescence technique. This alloantigen was expressed in 66.44% patients with RHD as compared with 14% of the normal population. A high relative risk (RR = 11.13) indicated a strong association of D8/17 B cell alloantigen with rheumatic heart disease. Increase in the frequency of the marker was observed with increasing age up to the fifth decade (40-49 years) in these patients. However, the frequency of this alloantigen, in the present study, in North Indian patients with rheumatic heart disease is lower than that reported in the American population.

Multi-choice food preference behaviour of the Indian mole rat Bandicota bengalensis

Multi-choice food preference behaviour of the Indian mole rat Bandicota bengalensis has been studied with 4 and 8 foods consisting of cereals and a pulse in rat pens which had floor area of 143 x 94 cm and 143 x 94 plus 220 x 82 cm, respectively, and separate food and nest boxes. Nine combinations of three texture forms of 4 foods and one combination of 8 foods were tested. Significant differences were observed in the daily consumption of different foods irrespective of the daily clock-wise rotation in the location of the foods. The number of available foods, their taste and textural qualities were found to influence the feeding responses of B. bengalensis. In multi-choice feeding tests with 4 foods, small sized and less harder grains as of rice and millet were eaten more than those of maize and gram, while the maize flour was more preferred than the flour forms of other grains. Compared to other foods in any combination, rice in its whole (W), cracked (C) and flour (F) forms was generally eaten more than the W and C forms of maize and gram and F form of gram and millet. However, the 8 foods were eaten in the following order of preference: millet (W) > millet (C) > jowar (C) > wheat (C) > rice parmal (C) > rice basmati (C) > gram (C) > maize (C). The mole rat appeared to establish a particular order of preference of foods on the first day of feeding, and that was maintained on subsequent days by daily exploration and sampling of all foods. The particular patterns of food preference, as established in combinations of 4 foods and 8 foods, were not influenced significantly by the changes in location of foods among similar and familiar feeding sites of the rats.

Cloning and characterization of the yeast chaperonin HSP60 gene

The heat-shock protein, HSP60, is abundant in prokaryotes and eukaryotes and is required in the assembly of specific proteins. We have cloned the Saccharomyces cerevisiae HSP60 gene from a lambda gt11 genomic library using monoclonal antibodies, have obtained its sequence, determined its transcription start point, and shown that it exists as a single copy. The predicted HSP60 contains a mitochondrial target sequence and exhibits striking amino acid sequence similarity to its counterparts in bacteria, plants, and humans. These data indicate a high level of evolutionary conservation and are consistent with the suggestion of evolutionarily conserved function [Hemmingsen et al., Nature 333 (1988), 330-334].

Haemorrhage in cerebral toxoplasmosis. A report on a patient with the acquired immunodeficiency syndrome

A patient with the acquired immunodeficiency syndrome (AIDS) presented to hospital with a haemorrhagic cerebral lesion. The lesion was biopsied and electron microscopy confirmed a diagnosis of toxoplasmosis. Although known in congenital cases, haemorrhagic infarction is unknown in adults suffering from cerebral toxoplasmosis. Severe vasculitis with subsequent thrombosis and extensive fibrinoid necrosis of the vessel wall or direct parasitism of endothelial cells with subsequent destruction and seepage of blood appear to be the possible mechanisms in a situation where the T-cell immune mechanism and tissue cell response are compromised. Other intracerebral haemorrhagic lesions in AIDS were reviewed.

Primary structure of a human mitochondrial protein homologous to the bacterial and plant chaperonins and to the 65-kilodalton mycobacterial antigen

The complete cDNA for a human mitochondrial protein designated P1, which was previously identified as a microtubule-related protein, has been cloned and sequenced. The deduced amino acid sequence of P1 shows strong homology (40 to 50% identical residues and an additional 20% conservative replacements) to the 65-kilodalton major antigen of mycobacteria, to the GroEL protein of Escherichia coli, and to the ribulose 1,5-bisphosphate carboxylase-oxygenase (rubisco) subunit binding protein of plant chloroplasts. Similar to the case with the latter two proteins, which have been shown to act as chaperonins in the posttranslational assembly of oligomeric protein structures, it is suggested that P1 may play a similar role in mammalian cells. The observed high degree of homology between human P1 and mycobacterial antigen also suggests the possible involvement of this protein in certain autoimmune diseases.

Stress proteins may provide a link between the immune response to infection and autoimmunity

Stress proteins are frequently the target of humoral and cell-mediated immune responses to infection. These proteins belong to highly conserved gene families and there is substantial sequence homology between antigens produced by pathogenic organisms and the corresponding proteins from mammalian cells. Human T cells from sites of infectious and autoimmune lesions proliferate in response to stress proteins, and mapping of antigenic determinants on a mycobacterial stress protein shows that both species specific and highly conserved, 'self-like', regions of the molecule can take part in immune recognition. It is proposed that the lymphocyte population induced in response to stress proteins of pathogens during infection includes cells capable of autoimmune recognition of the corresponding self protein. Local accumulation of self stress proteins--in response to viral infection, for example--may subsequently provide a stimulus for proliferation of such autoreactive lymphocytes, thereby triggering a cycle of events which may contribute to the pathological damage associated with autoimmune disease.

Short-chain alkanols and the functional efficiency of the Ca pump in the sarcoplasmic reticulum of rabbit skeletal muscles

The effect of 10 low molecular mass alkanols on the activity of Ca-ATPase (EC 3.6.1.38), Ca uptake and Ca efflux as well as the functional efficiency of the Ca pump in the fragmented sarcoplasmic reticulum of rabbit skeletal muscles has been studied. Some alkanols, especially when taken at low concentration, have been found to stimulate the activity of the Ca pump and Ca-ATPase, namely tert-butanol, isopropanol and ethanol (from the group of hydrophilic alkanols), and pentanol, isopentanol and hexanol (from the more hydrophobic alkanols). Methanol (from the first group) and isobutanol, butanol and propanol (from the second) do not stimulate the Ca pump compared with the control. The specific effect of different alkanols cannot be explained in terms of a unitary mechanism based on 'fluidity' changes of the membrane. It is assumed that, at low concentrations, certain alkanols (or groups of related alkanols) are able to promote the specific transition of membrane proteins into the active state, whereas at higher concentrations all alkanols provide for the non-functional state of the proteins.

A randomized study of cyclosporine with and without prednisone in renal allograft recipients. Canadian Transplant Group

Sixty-nine patients receiving Cs after cadaveric or LRD renal transplants were randomly allocated to receive prednisone or no prednisone beginning on the day of transplant. There were 36 in the prednisone group and 33 in the group assigned to no prednisone. Of these latter, only seven (21%) never received prednisone and an additional four had one short course for rejection episodes (11%). Of the remaining 22 who were placed on continuous steroids, only 12 met rejection criteria and either some or all of the remainder probably had Cs nephrotoxicity. The patient and graft survival were better but not statistically so in the no-prednisone group (97% v 89%) and (88% v 78%), and the number of infections was only half that of the prednisone-treated group (22% v 42%). A policy of withholding steroids except for rejection episodes does not prejudice graft or patient survival in Cs-treated patients.