Molecular mimicry between a uveitopathogenic site of S-antigen and viral peptides. Induction of experimental autoimmune uveitis in Lewis rats.

S-Antigen (S-Ag) is a well characterized 45,000 m.w. photoreceptor cell protein. When injected into susceptible animal species, including primates, it induces an experimental autoimmune uveitis, a predominantly T cell-mediated autoimmune disease of the retina and uveal tract of the eye, and of the pineal gland. In this study we found an amino acid sequence homology between a uveitopathogenic site of S-Ag, several viral proteins and one additional nonviral protein. An experimental autoimmune uveitis and pinealitis was induced in Lewis rats with these different synthetic peptides, corresponding to the amino sequence of hepatitis B virus DNA polymerase, gag-pol polyprotein of Baboon endogenous virus and gag-pol polyprotein of AKV murine leukemia virus and potato proteinase inhibitor IIa, which contain three or more consecutive amino acids identical to peptide M in S-Ag. Lymph node cells from rats immunized with either peptide M or the different synthetic peptides showed a significant degree of cross-reaction. Mononuclear cells from monkeys (Macaca fascicularis) immunized with peptide M also showed significant proliferation when incubated with either peptide M or synthetic peptides as measured by in vitro lymphocyte mitogenesis assay using [3H]TdR. Based on our findings we conclude that a viral infection may sensitize the mononuclear cells that can cross-react with self proteins by a mechanism termed molecular mimicry. Tissue injury from the resultant autoantigenic event can take place in the absence of the infectious virus that initiated the immune response.     

Detection of Trp-P-1 and Trp-P-2, carcinogenic tryptophan pyrolysis products, in dialysis fluid of patients with uremia

In order to estimate the exposure levels of mutagenic and carcinogenic heterocyclic amines in humans, we developed a high-performance liquid chromatography method to detect 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1) and 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2) in dialysis fluid of patients with uremia. Using this methods, dialysis fluid of 12 patients who had received hemodialysis treatment or continuous ambulatory peritoneal dialysis was examined. Trp-P-1 was detected in dialysate of all uremic patients (727 +/- 282 pmoles, n = 12). In patients who had been treated with continuous ambulatory peritoneal dialysis, the average amount of Trp-P-1 found in whole dialysate (6 l) per day was 710 +/- 203 pmoles (mean +/- S.D., n = 8). Moreover, Trp-P-2 could be detected in 5 out of 12 patients (206 +/- 85 pmoles, n = 5). These results indicate that patients with uremia are actually exposed to carcinogenic tryptophan pyrolysis products. The average exposure level of Trp-P-1 in uremic patients apparently exceeded 710 pmoles (150 ng) per day.     

Transport and Fixation of Inorganic Carbon during Photosynthesis in Cells of Anabaena Grown under Ordinary Air: III. Some Characteristics of the HCO3--Transport System in Cells Grown under Ordinary Air

In cells of cyanobacterium Anabaena variabilis grown under ordinaryair (low-CO₂ cells), the transport of both CO₂ and HCO₃^–was significantly enhanced by Na⁺. This effect was pronouncedas the external pH increased. When low-CO₂ cells were treatedwith an inhibitor of carbonic anhydrase (CA), only CO₂ transportbut not HCO₃^– transport, was inhibited. The initial rateof photosynthetic carbon fixation as a function of the concentrationof internal inorganic carbon (IC) was practically the same irrespectiveof whether CO₂ or HCO₃^– was externally supplied. Theseresults suggest that IC is actively transported through theplasma membrane in a form of HCO₃^– probably by some transporterand that the transmembrane Na⁺ gradient is involved in thisIC transport system. Free CO₂ may be hydrated by CA to HCO₃^–and then transported to the cells by this transporter. On the other hand, CO₂ is actively taken up by cells grown withair containing 5% CO₂ (high-CO₂ cells) though the enhancingeffect of Na⁺ was much smaller in high- CO₂ cells than in low-CO₂cells. The initial rate of fixation as a function of internal IC concentrationindicated that the rate of the carboxylation reaction of accumulatedIC is higher in I0W-CO₂ cells than in high-CO₂ cells. The studieswith ethoxyzolamide indicated that even in low-CO₂ cells, CAdoes not function inside Anabaena cells. These results suggestthat inside the low-CO₂ cells of Anabaena, some mediator(s)facilitates the transport of IC to RuBPCase. (Received January 23, 1987; Accepted April 24, 1987)     

Transport and Fixation of Inorganic Carbon during Photosynthesis of Anabaena Grown under Ordinary Air. I. Active Species of Inorganic Carbon Utilized for Photosynthesis

Inorganic carbon transport during photosynthesis of cyanobacteriumAnabaena variabilis grown under ordinary air was investigatedby supplying ¹⁴CO₂ or H¹⁴CO₃^– solution to three differentstrains. Both CO₂ and HCO₃^– were accumulated within thealgal cells. In the cell suspension from which dissolved inorganiccarbon had been depleted by pre-illumination, CO₂ was transportedand accumulated faster than HCO₃^–. When the concentrationof HCO₃^– injected into the cell suspension of A. variabilisM3 was 25 times as high as that of CO2 (the expected ratio atequilibrium at pH 7.8), the initial rates of fixation of bothinorganic carbon species were practically the same. On the otherhand, when ¹⁴CO₂ or H¹⁴CO₃^– was added under steady statephotosynthetic conditions, both carbon species were transportedat similar rates. The ratio of fixed to transported carbon measuredafter the initial 5 s was only 23–27% regardless of thecarbon species supplied. This percentage is much lower thanthat reported for Chlorella cells. ¹ To whom reprint requests should be addressed (Received June 30, 1986; Accepted December 16, 1986)     

Isolation and characterization of a novel 2-aminoethylphosphonyl-glycosphingolipid from the sea hare, Aplysia kurodai

A novel phosphonoglycosphingolipid named SGL-I' containing 1 mol of 2-aminoethylphosphonate residue was isolated from the skin of Aplysia kurodai using two silicic acid chromatography systems. Data obtained on methanolysis, permethylation, mild acid hydrolysis, and hydrogen fluoride treatment combined with thin-layer chromatography, gas liquid chromatography, gas chromatography-mass spectrometry, and proton magnetic resonance spectrometry showed that this glycolipid was 3-O-MeGal beta 1----3GalNAc alpha 1----3[6'-O-(2-aminoethylphosphonyl)Gal alpha 1----2]Gal beta 1----4Glc beta 1----1Ceramide. Palmitic acid, octadeca-4-sphingenine and anteiso-nonadeca-4-sphingenine are its major aliphatic components. The new glycolipid has essentially the same structure as another major phosphonoglycosphingolipid in the skin of Aplysia, SGL-II, that contains 2 mol of 2-aminoethylphosphonate residue, suggesting a metabolic relationship between the two.     

Identification of a family of high molecular weight tumor-associated glycoproteins

The monoclonal antibody (MAb) designated DF3 was prepared against a human breast carcinoma metastatic to liver. This MAb reacts with a high molecular weight glycoprotein detectable in human breast carcinomas and human milk. In contrast, MAb F36/22 was prepared against the MCF-7 breast carcinoma cell line, MAb 115-D8 against human milk fat globule membrane (HMFGM) and MAb Ca1 against the HEp-2 human laryngeal carcinoma cell line. These MAb have similar patterns of reactivity with normal tissues and tumors based upon immunoperoxidase staining. In the present study we have monitored reactivity of these MAb against DF3 antigen purified from human breast carcinoma cell lines (MCF-7, BT-20) and HMFGM. Solid phase immunoassays and immunoblotting demonstrate that MAb DF3, F36/22, 115-D8, and Ca1 all react with the same purified DF3 antigen. Furthermore, immunoblot analysis indicates that the DF3 antigen reactive with these MAb differs structurally in preparations from breast carcinoma cells and HMFGM. We also demonstrate that MAb F36/22 completely inhibits MAb DF3 binding in competitive blocking assays. In contrast, the results indicate that MAb 115-D8 and Ca1 only partially block MAb DF3 reactivity and the extent of this inhibition varies with DF3 antigen purified from breast carcinoma cells and HMFGM. Taken together, these findings with multiple MAb prepared against a variety of immunogens suggest that existence of a family of related but not identical high molecular weight tumor-associated glycoproteins.     

Nuclear DNA content as an indicator of chemosensitivity in small-cell carcinoma of the lung

The relationship between the nuclear DNA histogram pattern of tumor cells obtained by bronchoscopic brushing and the response to combination chemotherapy (Cytoxan + Adriamycin + Vincristine) was studied in 28 patients with small-cell carcinoma of the lung. Microspectrophotometric analysis of the tumor cells showed a near-diploid nuclear DNA pattern in 18 patients and a hyperdiploid pattern in 10 patients. Eight of the ten patients with the hyperdiploid pattern showed a good response (complete or partial response) to the chemotherapy. However, of the 18 patients with the near-diploid DNA pattern, only 2 displayed a good response; the remaining 16 patients exhibited no response. The hyperdiploid DNA pattern of tumor cells was thus associated with a better response to chemotherapy than was the near-diploid pattern. These results indicate that the nuclear DNA histogram pattern may be an indicator for predicting the degree of response to chemotherapy in small-cell carcinoma of the lung.     

Serum free thyroxine and thyroxine-binding globulin concentrations in early phase of subacute thyroiditis

Serum total thyroxine (T4), total triiodothyronine (T3), T4-binding globulin (TBG), free T4(FT4) and free T3(FT3) concentrations and the T3-uptake(T3-U) value were estimated in 11 patients with subacute thyroiditis, and compared with the same parameters in 11 patients with Graves' disease, whose serum T4 concentrations were similar to the former group. Seven patients with subacute thyroiditis, who were treated with dicrofenac sodium alone, were investigated as to the sequential changes in serum parameters during their clinical courses. The mean serum T3-U value and FT4, T3 and FT3 concentrations in patients with subacute thyroiditis were increased, but all were significantly lower than those in patients with Graves' disease (p less than 0.01, p less than 0.001, p less than 0.001 and p less than 0.001, respectively). Three patients with subacute thyroiditis, who showed shorter duration of symptoms than 10 days, had serum TBG excess. Thus the mean (+/- SD) serum TBG concentration (26.5 +/- 8.4 micrograms/ml) was significantly higher than that (18.3 +/- 2.9 micrograms/ml) in patients with Graves' disease (p less than 0.02). The ratios of serum T3 to T4 and FT3 to FT4 in patients with subacute thyroiditis were also significantly lower than those in patients with Graves' disease (p less than 0.001 and p less than 0.001, respectively). The serum FT4 in 7 patients treated with dicrofenac sodium alone decreased to the normal range after 3 to 8 weeks from the onset of the illness. In 3 patients with TBG excess and one patient (TBG; 29.0 micrograms/ml), serum TBG declined in consequence of the serum FT4 normalization.(ABSTRACT TRUNCATED AT 250 WORDS)