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Biomedical subjects

G Colucci

Publications and source records attributed to G Colucci.

At least 127 records · Page 7Linked to original sources
PubMed1987

Interactions between hepatitis B virus and polymeric human albumin. I. Production of monoclonal anti-idiotypes (anti-anti-polymeric human albumin) which recognize hepatitis B virus surface antigen.

In an attempt to characterize the polymeric human albumin (polyHSA) receptor expressed on hepatitis B virus and hepatocytes, we have used a human anti-polyHSA IgG to generate monoclonal anti-idiotypes (anti-Id) which bear the internal image of polyHSA and mimic its binding activity. Two monoclonal anti-Id antibodies, 63.14 and 70.F9, were strongly reactive in both radioimmunoassay and enzyme-linked immunosorbent assay (ELISA) with the F(ab')2 of the immunogen as well as with purified hepatitis B surface antigen (HBsAg) expressing various subtypes. The specificity of the binding of anti-Id to HBsAg was confirmed in direct ELISA and by Western blot analysis. These experiments also showed that the anti-Id bind to a site expressed on the major 24-kDa protein of HBsAg particles, and that this recognition is specifically inhibited by polyHSA. Experiments on cellular staining and radioimmunoprecipitation on HBsAg-positive and -negative cell lines showed that the anti-Id recognize intracellular HBsAg but not other liver cell proteins, including the putative polyHSA receptor. These data indicate, therefore, that the monoclonal anti-Id mimic the binding activity of polyHSA and recognize its binding site on the virus. The inability of both anti-Id to react with the hepatocyte surface suggests either the absence of a specific hepatic polyHSA receptor or the expression of one with a different configuration.

Antibodies, Monoclonal↗
PubMed1987

Interactions between hepatitis B virus and polymeric human serum albumin. II. Development of syngeneic monoclonal anti-anti-idiotypes which mimic hepatitis B surface antigen in the induction of immune responsiveness.

We used monoclonal anti-idiotypes (anti-Id) 63.14, previously shown to mimic polymeric human serum albumin (polyHSA) and bind its receptor on hepatitis B surface antigen (HBsAg), to produce syngeneic monoclonal anti-anti-Id (Ab3) which could bear the internal image of HBsAg and mimic its immunogenicity in vivo. Nine hybridomas obtained from spleen cells of BALB/c mice immunized with 63.14 were isolated, which were able to inhibit the binding of alkaline phosphatase-conjugated 63.14 to HBsAg. Both direct and competition enzyme-linked immunosorbent assay (ELISA) showed that 4 of these clones were able to mimic HBsAg since they reacted with polyHSA and inhibited the binding of monoclonal and polyclonal anti-HBsAg to the viral antigen. To determine whether these Ab3 could induce an immune response against HBsAg in vivo, we injected a series of rabbits with Ab3 G11 or HBsAg and tested their sera after the second boost. ELISA, radioimmunoassay and Western blot experiments showed that G11 was as effective as HBsAg in inducing a specific anti-HBsAg immune response. These data indicate that our Ab3 can mimic HBsAg both in vitro and in vivo and might be useful as alternative vaccine for HBV infection.

Animals↗
PubMed1986

In situ characterization of the cell-surface antigens of the mononuclear cell infiltrate and bile duct epithelium in primary biliary cirrhosis.

To analyze the tissue distribution of mononuclear cells and HLA antigens in primary biliary cirrhosis, we studied liver biopsies of 12 patients at different stages of the disease, using the avidin-biotin-peroxidase technique and monoclonal antibodies directed against T and B lymphocytes, T-cell subsets, macrophages, NK/K cells, dendritic cells, and HLA class I and II antigens. To evaluate the proportion of activated T cells we used anti-interleukin-2-receptor antibodies and a double-staining technique for T cells and class II HLA antigens. In all biopsies activated T cells predominated in the portal areas and around the damaged bile ducts. T4 cells almost always outnumbered T8 cells. While B cells, NK/K cells, and dendritic cells were always scarce, macrophages constituted about 30% of the cellular infiltrate. Biliary epithelium, which normally expresses HLA class I antigens, displayed mainly HLA class II antigens. The predominance of T4 cells around the bile ducts, which express class II antigens, suggests that class II-restricted T4 lymphocytes may mediate liver damage in primary biliary cirrhosis.

Antigens, Surface↗
PubMed1986

Preparation and characterization of human monoclonal antibodies directed against the hepatitis B virus surface antigen.

The hepatitis B surface antigen (HBsAg) is highly immunogenic and induces an antibody response which is protective in vivo against hepatitis B virus (HBV) infection. Human monoclonal antibodies specific for HBsAg were produced, which could have potential therapeutic applications. Lymphocytes obtained from a vaccinated donor were stimulated in vitro and fused with the human myeloma cell line GM 4672, and eight hybridomas were obtained. Three of these clones, which reacted in an ELISA against the HBsAg vaccine, were expanded, subcloned and further analyzed. The subclones E7C2, C4C10, and D5B2 were able to bind to different HBsAg preparations, which express various subtypes, and recognized the major HBsAg peptides in Western blot analysis. Cross-inhibition experiments showed that E7C2, C4C10 and D5B2 are directed against the same epitope and have an affinity constant ranging from 5 X 10(7) to 3.3 X 10(9) M. Furthermore, these antibodies stained the surface and cytoplasm of the HBsAg-secreting cell lines PLC/PRF/5 and 4.10. The production of immunoglobulins varies from 0.3 to 1.3 micrograms/ml/10(6) and has remained stable over a period of 8 months. These human monoclonal antibodies, which appear to be directed against an antigenic determinant common to all HBsAg subtypes, could be useful in the study of HBV-related liver diseases as well as in their diagnosis and experimental therapy.

Antibodies, Monoclonal↗
PubMed1984

[Differentiated carcinoma of the thyroid].

Experience in differentiated thyroid carcinoma surgery is presented. It is considered that, although these neoplasias are not very aggressive, they should be treated radically with a combination of surgery and radioisotopes.

Adenoma↗
PubMed1983

In situ characterization by monoclonal antibodies of the mononuclear cell infiltrate in chronic active hepatitis.

To characterize the inflammatory infiltrate of chronic active hepatitis we have examined 26 liver biopsy specimens [16 hepatitis B surface antigen-negative and 10 hepatitis B surface antigen-positive] with monoclonal antibodies and antiimmunoglobulins that react against the following mononuclear cell populations: T cells, T4 cells, T8 cells, monocytes-macrophages, Ia-positive cells, surface Ig-bearing cells, natural killer/killer cells. A biotin-avidin-fluorescein technique was used and the number of positive cells was counted in a portal tract that was more severely involved. The T cells predominate in all the specimens. The T4:T8 cell ratio and the number of T and T4 cells in the hepatitis B surface antigen-negative patients are higher than in the hepatitis B surface antigen-positive patients. While natural killer/killer cells, surface Ig-bearing cells, and macrophages are always rare, Ia-positive cells are numerous and the double-staining technique demonstrates a fair number of cells displaying both T-cell and Ia markers. These findings, while not supporting a major role of killer cells in chronic active hepatitis, suggest a different alteration of T-cell subsets in hepatitis B surface antigen-positive and -negative chronic active hepatitis.

Adult↗
PubMed1980

[Probable stenocardial effects of combined oral contraceptives].

One case of myocardial infarction and one case of coronary insufficiency, observed in women treated with oral contraceptives, are presented. Pathogenetic hypotheses are put forward and stress is laid on the necessity of evaluating risk factors as well as carrying out the various hemogenic tests in these patients.

Adenosine Monophosphate↗
PubMedDate not supplied

Severe pneumonia in pregnancy three months after resolution of cutaneous zoster.

A 22 weeks pregnant women was affected by a life-threatening pneumonia and a paresis of the proximal muscles with cerebrospinal fluid pleocytosis. Her past medical history had been unremarkable except for recurrent episodes of paraumbilical herpes zoster. The clinical findings suggested a dissemination of varicella-zoster virus without skin lesions. Acyclovir was added to the therapy, and the clinical picture began to improve. Varicella-zoster virus DNA was detected in placental tissue by DNA-hybridisation analysis.

Acyclovir↗
PubMedDate not supplied

Case-control study of hepatitis B virus infection in chronic liver disease and hepatocellular carcinoma.

The prevalence of serum hepatitis B virus markers was studied in three groups of age- and sex-matched patients: a. 31 patients with liver cirrhosis and hepatocellular carcinoma (c-HCC); b. 31 patients with chronic liver disease (CLD) and c. 62 hospitalized control subjects. The overall exposure rate to the hepatitis B virus was 90% in c-HCC, 80% in CLD and 58% in control subjects. The prevalence of hepatitis B surface antigen (HBsAg) was 29%, 13% and 1.6% in the three groups, respectively. The prevalence of hepatitis B surface antibody was significantly lower in c-HCC (9.6%) than CLD (42%) and control subjects (40%). The serological evidence of continuous viral replication (HBsAg positivity or isolated high titre hepatitis B core antibody positivity) was more common in c-HCC (39%) than CLD (12%) and control subjects (1.6%). The prevalence and patterns of aggregation of serum hepatitis B virus markers were similar in the 31 patients with c-HCC and in 11 patients with HCC without concomitant liver cirrhosis (n-HCC). In conclusion, the overall exposure rate to the hepatitis B virus is similar in c-HCC and CLD. However, serological evidence of continuous viral replication is more common in the former group. A defective clearance of the hepatitis B virus in hepatocellular carcinoma is a possible explanation of the phenomenon. The strength of the association between hepatitis B virus infection and hepatocellular carcinoma appears to be similar in c-HCC and n-HCC.

Adult↗
PubMedDate not supplied

Detection of the hepatitis B virus major pre-core mutation by the amplification refractory mutation system technique.

HBeAg/anti-HBe seroconversion is associated, in some patients affected by type B chronic active hepatitis (CAH), with the occurrence of HBV pre-core mutants characterized by a common G-A change at codon 83. Since this mutation has important clinical correlations, we tried to develop a fast and reliable PCR test based on the amplification refractory mutation system (ARMS) technique, which has been successfully used to identify point mutations associated with genetic diseases. Following this approached, we analysed HBV particles isolated from 7 patients with anti-HBe CAH and previously characterized by DNA sequencing. Sera containing only wild type or mutant HBV DNA or a combination of both showed a discrete amplification product only in the presence of the specific wild type or mutant upstream primer. These results confirm the efficacy of the ARMS technique in detecting in a rapid and specific fashion the most common and clinically relevant HBV pre-core mutation.

Base Sequence↗