Infection of C3HeB/FeJ mice with the docile strain of lymphocytic choriomeningitis virus induces autoantibodies specific for erythrocyte Band 3

C3HeB/FeJ mice infected with the docile strain of lymphocytic choriomeningitis virus (LCMV-d) develop a persistent infection with a transient haemolytic anaemia. Immunoglobulin can be eluted from the red blood cells (RBC) of these mice but it cannot be detected on the RBC by a conventional antiglobulin test. The present study demonstrates that RBC from such mice bear erythrocyte autoantibodies which are predominantly of the IgG2a subclass, with lower levels of autoantibodies of the IgG1, IgG2b and IgG3 subclasses. To identify the target antigen the autoantibodies were eluted from the RBC of LCMV-infected mice. The eluted autoantibody bound to intact normal RBC and precipitated a 105000 MW component that corresponds to murine Band 3 protein. A monoclonal antibody derived from mice infected with LCMV-d also precipitated mouse Band 3, and reacted specifically by enzyme-linked immunosorbent assay against a purified preparation of Band 3. This study has shown that in C3H mice infected with LCMV-d which develop autoimmune haemolytic anaemia, the target autoantigen is erythrocyte membrane Band 3.

Does the presence of ANCA in patients with ulcerative colitis necessarily imply renal involvement?

BACKGROUND

ANCA are thought to play a pathogenic role in renal vasculitis. ANCA may also be detected in patients with diseases not usually associated with renal pathology, such as ulcerative colitis. Our study was conducted to determine if the presence of ANCA in patients with ulcerative colitis is associated with renal pathology.

METHODS

Eight ANCA-positive and five ANCA-negative patients with a histological and endoscopic diagnosis of active ulcerative colitis were investigated. Repeated complete urinalyses and determination of microalbuminuria and creatinine clearance were performed. Serum IgG and IgA ANCA were evaluated in all patients by indirect immunofluorescence and ELISA, and when detected the antibodies were further characterized by alpha granules preparation, myeloperoxidase, lactoferrin, and cathepsin G.

RESULTS

In both ANCA-positive and ANCA-negative patients renal function was normal or near normal and urinalyses (including microalbuminuria) failed to disclose any abnormalities. ANCA exhibited a perinuclear pattern in all ANCA-positive patients. Interestingly, none of the ANCA-positive patients had antibodies to myeloperoxidase or to alpha granules which are usually found in the sera of patients with ANCA-associated vasculitis, and only one had antibodies to lactoferrin. The ANCA specificity remained undetermined in the remaining seven patients. At the end of the 1-year observation period, all ANCA-positive patients remained ANCA-positive without developing symptoms, signs or laboratory abnormalities consistent with renal involvement.

CONCLUSIONS

Renal damage was not observed in ANCA-positive patients with ulcerative colitis even after 1 year of follow-up, suggesting that the ANCA found in these patients do not share the antigenic targets with the ANCA commonly found in renal vasculitis. Therefore the potential of ANCA of inducing renal lesions (if any) is dependent on their own antigenic specificity.

Characterization of T cell receptor single-chain Fv fragments secreted by myeloma cells

Myeloma cells have been used to produce milligram quantities of soluble alpha beta T cell receptor (TCR) molecules as single-chain polypeptides in which the TCR variable (V) domains are connected by a peptide linker (TCR scFv). Unlike most TCR scFv produced in bacteria, the purified TCR scFv were stable and showed no tendency to aggregate when kept at concentrations up to 10 mg/ml. Circular dichroism analyses of the TCR scFv indicated that they contained a high proportion of beta-pleated sheet structures. Since the V alpha subunits present in the TCR scFv contained their own signal sequences, they provided the opportunity to determine by N-terminal amino acid sequencing the position of the signal cleavage of three distinct mouse V alpha. Two of the experimentally determined signal cleavage sites differed from those previously predicted on the basis of biochemical and statistical criteria. The expression approach outlined in this report has been applicable to three distinct alpha beta TCR and should contribute to the large scale production of soluble TCR amenable to structural studies.

T-helper 1 dominated responses to erythrocyte Band 3 in NZB mice

Band 3, the red blood cell (RBC) anion channel protein, is the target autoantigen for the pathogenic RBC autoantibodies and T-helper (Th) cells in New Zealand Black (NZB) mice with autoimmune haemolytic anaemia (AIHA). To determine the subpopulation of these Th cells, they were stimulated with Band 3 and the profile of the cytokines elaborated by the responding cells was measured. NZB T cells stimulated with Band 3 produced high levels of the Th1 cytokine, interferon-gamma (IFN-gamma), but little or no interleukin-4 (IL-4), IL-5 or IL-10. Similar patterns were produced by NZB T cells responding to a spectrin preparation from the RBC membrane skeleton, or to mycobacterial heat-shock protein (hsp) 65 following immunization of mice with hsp 65 in incomplete adjuvant. By contrast, T cells from CBA mice similarly immunized with hsp 65 produced high levels of IL-4 and IL-5 in response to hsp 65. Examination of the isotype of the RBC-bound immunoglobulins in NZB mice revealed that immunoglobulin G2a (IgG2a) autoantibodies were the first to be detected in most mice and that later in the disease, IgG3 autoantibodies were often prominent. It is concluded that, contrary to expectation, the development of RBC autoantibodies in NZB mice is associated with Th1 cytokine-dominated responses.

Covalent assembly of a soluble T cell receptor-peptide-major histocompatibility class I complex

We used stepwise photochemical cross-linking for specifically assembling soluble and covalent complexes made of a T-cell antigen receptor (TCR) and a class I molecule of the major histocompatibility complex (MHC) bound to an antigenic peptide. For that purpose, we have produced in myeloma cells a single-chain Fv construct of a TCR specific for a photoreactive H-2Kd-peptide complex. Photochemical cross-linking of this TCR single-chain Fv with a soluble form of the photoreactive H-2Kd-peptide ligand resulted in the formation of a ternary covalent complex. We have characterized the soluble ternary complex and showed that it reacted with antibodies specific for epitopes located either on the native TCR or on the Kd molecules. By preventing the fast dissociation kinetics observed with most T cell receptors, this approach provides a means of preparing soluble TCR-peptide-MHC complexes on large-scale levels.

Quantitation of erythrocyte-bound IgG subclass autoantibodies in murine autoimmune haemolytic anaemia

A quantitative and sensitive cellular enzyme-linked immunosorbent assay was developed for determining the number of molecules of IgG of each subclass bound to the surface of murine red blood cells (RBC). To develop standard titration curves, RBC from normal mice were treated with tannic acid and coated with a known concentration of purified myeloma of each IgG subclass. The quantity of each subclass bound to the surface of erythrocytes was determined by calculating the protein concentration of the bound IgG, which was then converted into number of molecules of IgG/RBC. The assay was used to quantify the number of autoantibodies of all four IgG subclass bound to the erythrocytes of mice injected with rat RBC. Twenty one days after the first immunisation, a mean number of 84,000 molecules of IgG1/RBC were detected, which increased to 114,500 molecules/RBC on day 28. On days 56 and 96 the mean concentration of IgG1 remained high, however by day 110 the mean level of IgG1 had decreased slighty to 69,500 molecules/RBC. By contrast, the mean concentration of IgG2a autoantibodies was considerably lower throughout the experiment, starting at 40,200 molecules/RBC on day 21 and dropping to 2,500 molecules/RBC by day 110. The mean quantities of IgG2b and IgG3 autoantibodies were similar to each other, and intermediate between the levels of IgG1 and IgG2a autoantibodies.

Autoreactive T cell specificity in autoimmune hemolytic anemia of the NZB mouse

Splenic T cells from Coombs'-positive New Zealand Black (NZB) mice proliferated consistently in vitro in response to the integral red blood cell (RBC) membrane protein Band 3, the antigen previously shown to be the target for the pathogenic RBC autoantibodies. The responding cells predominantly express CD4 and the proliferative response is blocked by antibodies to the NZB major histocompatibility complex class II but not by antibodies to an irrelevant H-2 haplotype. NZB splenic T cells also proliferated in response to the internal membrane skeleton protein spectrin. By contrast, T cells from BALB/c and DBA2 mice, which bear the same H-2 haplotype as NZB mice, but which do not develop autoimmune hemolytic anemia (AIHA), fail to respond to Band 3. It is considered that these results support the hypothesis that Band 3-reactive T cells provide help for the production of pathogenic anti-Band 3 autoantibodies in NZB mice. T cells from Coombs'-negative NZB mice as young as 3 weeks old proliferated in response to Band 3; moreover, the RBC from Coombs'-negative mice bore elevated levels of autoantibody as judged by a sensitive direct enzyme-linked anti-globulin test. Thus, the pathology of AIHA develops at a much earlier age than was thought previously.

Linfadenectomia laparoscopica e Mini-lap: Attualità, limiti ed indicazioni

The authors, according to their preliminary experience with laparoscopic lymphadenectomy and Mini-lap performed for the staging of 15 patients with prostatic carcinoma, have compared the morbidity, the diagnostic accuracy rate and costs of these two techniques, referring critically to international literature and evaluating the real efficacy of a delayed laparoscopic pelvic lymphadenectomy prior to radical prostatectomy. Moreover they have tested the general applicability of the equation by Roach et al., which was empirically derived from a nomogram reported by Partin et al., to predict the risk of lymph node metastasis, applying it to a selected group of patients who underwent radical prostatectomy from 1992 to 1994 in order to maximize the utility of lymphadenectomy for prostatic cancer staging.

Relazione su: “La prostatectomia radicale oggi: Problematiche attuali e nuove terapie alternative”

The Authors present a report about 107 patients treated by radical retropubic prostatectomy over a period of 6 years in the Urologic Department of Gorizia Hospital. They compare their data with those given in the latest scientific articles, results being similar. Noticing that many cases are still understaged, they emphasize the opportunity of a joint contribution by surgeon and oncologist in fighting the disease.

La progressione di malattia dopo prostatectomia radicale: Quale strategia terapeutica?

Cancer progression, following radical prostatectomy, is distinguished by its biological or clinical aspects and is a controversial subject. As adjuvant therapy there is hormonal treatment and radiation therapy or a combination of both. The lack of standardization of the main pathological features of prostate cancer does not allow an accurate valuation of the results from the most important studies. A real efficacy in local or distant control seems to be certain, while the influence on disease-free survival is more uncertain. After a review of the most common options of treatment, the Authors present their results from 107 radical prostatectomies carried out between 1989 and 1994.

Quail sono i limiti attuali dell'indicazione alla prostatectomia radicale?

Progressive improvement in surgical techniques has considerably reduced complications subsequent to radical prostatectomy, which has been considered first choice treatment for about a decade. At the same time two lines of thought have been established regarding the more or less extended indication for surgery. Today's greater knowledge concerning the biological behaviour of the neoplasm and the significance of the prognostic factors should stimulate reflection about the selection of patients for more effective surgery.

Anthocyanins in grapes and grape products

The types of anthocyanins occurring in grapes, wines, and juices are described and their distribution documented. Recent work on the evaluation of red wine color during storage and aging is reviewed. Molecular interactions between anthocyanins and some of the other red wine molecules are shown to be associated with development of new pigments whose formation explains the subtle color changes and stabilization occurring on aging of red wines. A detailed description of the recovery of anthocyanins from grape pomace and production of natural red colorants is also given.

Tissue immunoglobulin G subclasses observed in immune-mediated dermatopathy, deep pyoderma and hypersensitivity dermatitis in dogs

A panel of monoclonal antibodies has been used to define three of the four subclasses of canine immunoglobulin G (IgG2, IgG3 and IgG4) in formalin-fixed tissues. These reagents, together with a polyclonal antiserum specific for the Fc region of canine IgG, were used in an immunohistochemical study of biopsies of skin from five normal dogs and from the lesions of canine pemphigus foliaceus in seven dogs, discoid lupus erythematosus in eight dogs, bullous pemphigoid in one dog, cutaneous drug eruption in two dogs, deep pyoderma in 13 dogs and hypersensitivity dermatitis in eight dogs. IgG autoantibody was identified in the skin of all the dogs with immune-mediated dermatoses by using the polyclonal reagent, and antibody of the IgG2 and/or IgG4 subclass was identified in the epidermis of three of the dogs with pemphigus foliaceus, two of those with discoid lupus erythematosus and in the dog with bullous pemphigoid. In all the lesions, the infiltrate of dermal plasma cells consisted of similar numbers of IgG2 and IgG4 bearing cells, with relatively few IgG3 positive cells. The total number of these cells was generally approximately the same as or greater than the number of cells labelled with the polyclonal reagent. There was no significant difference between the IgG-bearing plasma cell infiltrate in German shepherd dogs with deep pyoderma and that in dogs of other breeds. The infiltration of IgG2 and IgG4 bearing plasma cells into the skin of dogs with a range of cutaneous disorders was related to the selectively enhanced serum levels of these subclasses in the diseased dogs.

Development of an enzyme-linked immunosorbent assay for the detection of IgG subclasses in the serum of normal and diseased dogs

The present study describes the development of an enzyme-linked immunosorbent assay capable of quantifying serum antibody of all four canine IgG subclasses. A panel of subclass-restricted and subclass-specific monoclonal antibodies was used to measure IgG subclasses in the serum of healthy dogs, as well as in dogs with a range of clinical diseases. The subclasses have been redefined as IgG1, IgG2, IgG3 and IgG4 based on a comparison with the relative concentration and electrophoretic mobilities of human IgG subclasses. In serum samples from healthy dogs, the concentration of IgG1 (mean, 8.17 +/- 0.95 mg ml-1) and IgG2 (mean, 8.15 +/- 3.16 mg ml-1) were very similar and considerably higher than the levels of IgG3 (mean, 0.36 +/- 0.43 mg ml-1) and IgG4 (mean, 0.95 +/- 0.45 mg ml-1). There was no apparent difference in the level of subclasses between the different breeds comprising this normal population. Sera from dogs with a range of immune-mediated or inflammatory diseases all had markedly elevated levels of IgG2 (more than 13 mg ml-1), but IgG1 decreased (less than 4 mg ml-1) to levels below the normal range.

Preparation of monoclonal antibodies specific for the subclasses of canine IgG

Canine IgG is composed of four subclasses, which are defined as IgG1, IgG2, IgG3 and IgG4 on the basis of data from fast protein liquid chromatography, and their electrophoretic mobilities and relative concentrations in serum. This paper describes the preparation of mAbs specific for determinants on canine IgG2, IgG3 and IgG4. The mAb specific for IgG2 resulted from a conventional immunisation protocol. The mAb specific for IgG3 was a result of immunisation with IgG3 combined with the suppression of the immune response to IgG1 by passively administered anti-IgG1 antibody. The mAb specific for IgG4 resulted from immunisation with Fab or Fc fragments which were obtained by the cleavage of the IgG4 molecule with papain. The specificity of each mAb was established by using an enzyme-linked immunosorbent assay which showed that all three specific clones recognised a determinant in the Fd region of the canine immunoglobulin molecule.

T cell development in mice lacking the CD3-zeta/eta gene

The CD3-zeta and CD3-eta polypeptides are two of the components of the T cell antigen receptor (TCR) which contribute to its efficient cell surface expression and account for part of its transducing capability. CD3-zeta and CD3-eta result from the alternative splicing of a single gene designated CD3-zeta/eta. To evaluate the role of these subunits during T cell development, we have produced mice with a disrupted CD3-zeta/eta gene. The analysis of thymocyte populations from the CD3-zeta/eta-/- homozygous mutant mice revealed that they have a profound reduction in the surface levels of TCR complexes and that the products of the CD3-zeta/eta gene appear to be needed for the efficient generation and/or survival of CD4+CD8+ thymocytes. Despite the almost total absence of mature single positive thymocytes, the lymph nodes from zeta/eta-/- mice were found to contain unusual CD4+CD8- and CD4-CD8+ single positive cells which were CD3-. In contrast to the situation observed in the thymus, the thymus-independent gut intraepithelial lymphocytes present in zeta/eta-/- mice do express TCR complexes on their surface and these are associated with Fc epsilon RI gamma homodimers. These results establish an essential role for the CD3-zeta/eta gene products during intrathymic T cell differentiation and further emphasize the difference between conventional T cells and thymus-independent gut intraepithelial lymphocytes.

The separation and identification by monoclonal antibodies of dog IgG fractions

Four fractions of IgG from normal dog serum have been successfully isolated by gel filtration followed by protein A and protein G affinity chromatography using the fast protein liquid chromatography (FPLC) system. Protein A chromatography produced three peaks: peak 1 was fallthrough material consisting of components which did not bind to protein A, peak 2 consisted of bound material eluting at pH 6, and peak 3 contained bound material eluting at pH 3.5. The three peaks were then subjected individually to protein G affinity chromatography. Peak 1 from protein A chromatography produced a fallthrough peak followed by a weakly binding component which eluted at pH 8, and was called peak w. Peak 2 from protein A chromatography bound to protein G and eluted as a single peak at pH 3.8, and was called peak x. Peak 3 from protein A chromatography emerged as two separate peaks (y and z) off the protein G column; peak y bound and eluted at pH 4.1, and peak z bound weakly to protein G and emerged as a broad band at pH 8. Peaks w, x, y and z have been named gamma w, gamma x, gamma y and gamma z, respectively, and there purified IgG fractions were used to immunize mice for the preparation of monoclonal antibodies (McAbs). To date, two sets of McAbs have been produced: one which recognizes an epitope present in both gamma w and gamma z fractions and another set of McAbs which recognizes an epitope in the gamma x and gamma y fractions.