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A Bertoletti

Publications and source records attributed to A Bertoletti.

43 records · Page 3Linked to original sources
PubMed1989

The preS1 antigen of hepatitis B virus is highly immunogenic at the T cell level in man.

14 hepatitis B vaccine recipients who showed high titers of anti-hepatitis B surface antibodies in serum after booster immunization with a polyvalent hepatitis B surface antigen vaccine that contained trace amounts of hepatitis B virus (HBV) preS1 and preS2 envelope antigens were studied for their in vitro T cell response to these antigens. All 14 subjects displayed a significant proliferative T cell response to the S/p25 envelope region encoded polypeptide; 8 also responded to preS1, while only 1 showed a significant level of T cell proliferation to preS2. Limiting dilution analysis demonstrated that the frequency of preS-specific T cells in two of these vaccine recipients was higher than that of S/p25-specific T cells. T cell cloning was then performed and a total of 29 HBV envelope antigen-reactive CD4+ cloned lines were generated from two preS-responsive vaccines. 21 of these lines were S/p25 specific, 7 preS1 specific, and 1 preS2 specific. Taken together, all these results suggest that the preS1 antigen may function as a strong T cell immunogen in man.

Chromobox Protein Homolog 5↗
PubMed1989

[Immune response to plasma-derived hepatitis B vaccine in hospital health personnel of Parma].

In January 1984 a hepatitis B vaccination campaign was started in health care workers of Hospital of Parma. Within 3 years, of the 953 subjects submitted to serologic screening, 446 were eligible and 409, serum negative for HBV, completed the vaccination. 202 received HB-VAX vaccine (M.S.D.) intramusculary into the buttock at 0.1 and 6 months, and 208 received HEVAC-B vaccine (Pasteur) into deltoid region at 0, 1, 2 and 12 months. After the booster injection, percent of seroconversion (anti-HBs greater than 10 UI/l) and anti-HBs antibody titres were significantly (p less than 0.01) higher in HEVAC-B recipients (95.6%, mean anti-HBs titres = 6400 UI/l), than in the subjects vaccined with HB-VAX (77.1%, mean anti-HBs titres = 2703 UI/l). There was no significative difference in immune response in both groups with respect to age, sex or occupational category. Three hepatitis B infections were identified in HB-VAX recipients, but no one in individuals vaccined with HEVAC-B. No participants had serious adverse effects, minor side effects occurred with equal frequency in both groups. In general, both plasma-derived vaccines have proved to be highly immunogenic, safe and well tolerated in health care workers, however HEVAC-B vaccine, since contains S and pre-S ag, has shown a more satisfactory immunogenic effect.

Adult↗
PubMed1984

Sulfonylureas enhance in vivo the effectiveness of insulin in type 1 (insulin dependent) diabetes mellitus.

Indirect evidence suggests that sulfonylureas, in addition to stimulating insulin release, exert additional effects at extrapancreatic levels which are of value in the management of type 2 diabetes. In order to characterize in vivo some of these effects, insulin sensitivity was studied in 9 type 1 diabetics with no residual insulin secretory activity, during treatment with chlorpropamide (250 mg b.i.d. for 8 days) and with glipizide (5 mg t.i.d. for 8 days). Employing the glucose clamp technique with the aid of an artificial pancreas (Biostator), glucose disposal during insulin infusion (0.1 U/kg in 60 min) was calculated by the amount of glucose required to keep the blood glucose at preinfusion levels. Chlorpropamide and glipizide administration was accompanied by a significant increase of the amount of glucose required to clamp blood glucose levels, while serum (free) insulin levels were superimposable during the different clamping studies. In the absence of endogenous insulin release, these data strongly suggest that the two sulfonylureas employed enhance in vivo the peripheral sensitivity to insulin. Further studies are required to indicate a preferential site of action (liver, muscle, adipose tissue) of sulfonylureas.

Adolescent↗
PubMedDate not supplied

[The immunopathogenesis of hepatitis B].

Knowledge of hepatitis B immunopathogenesis has greatly improved in the last few years thanks to the development of new methods of lymphocyte culture and the introduction of molecular techniques in the study of the cell-mediated antiviral immune responses. Some of the immune mechanisms likely responsible for liver cell injury and viral clearance during hepatitis B have recently been characterized. By using synthetic peptides and high efficiency recombinant expression vectors. HLA class I restricted cytotoxic T cells specifically able to recognize the nucleocapsid antigen of the hepatitis B virus (HBV) have been isolated from the blood of patients with acute self-limited hepatitis B. The observation that this cytotoxic response is lacking or very weak in chronic patients who do not succeed in clearing the virus suggests a major role for cytotoxic T cells in terminating virus infection. Similar behaviour is shown by HLA class II restricted CD4+ T cells which express much stronger levels of response to HBV nucleocapsid antigens in acute than in chronic HBV infection. Whether these defective responses in chronic patients are due to an actual lesion of the host's immune system or to viral mutations affecting immune surveillance and thereby allowing virus escape, still remain open issues. A definitive answer to these questions will, we hope, provide the appropriate tools to devise effective immune therapies against chronic HBV infection.

B-Lymphocytes↗