Detection of receptors for polymerised human albumin by immunoperoxidase and immunoadherence in liver tissue of HBsAg chronic carriers.

Receptors for polymerised human albumin (pHSA-Rs) were detected in unfixed cryostat sections from HBsAg chronic carriers using direct immunoperoxidase and immunoadherence methods. Although pHSA-Rs were detected by both methods, the receptors detected by immunoperoxidase were associated with HBV and showed properties different from the receptors detected by immunoadherence. The double immunocytochemical staining which detected contemporaneously pHSA-Rs and HBsAg in the same cell showed that there are two types of infected hepatocytes: one capable of synthesizing pHSA-Rs and HBsAg and the other capable of synthesizing only HBsAg. The intrahepatocyte synthesis of pHSA-Rs does not correlate with the severity of chronic liver disease or with the presence of tissue HB core antigen

Analysis of mechanisms involved in the Cucumber mosaic virus satellite RNA-mediated transgenic resistance in tomato plants

Transgenic tomato (Lycopersicon esculentum Mill. cv. UC82) plants expressing a benign variant of Cucumber mosaic virus satellite RNA (CMV Tfn-satRNA) were generated. The transformed plants did not produce symptoms when challenged with a satRNA-free strain of CMV (CMV-FL). The same plant lines initially were susceptible to necrosis elicited by a CMV strain supporting a necrogenic variant of satRNA (CMV-77), but a phenotype of total recovery from the necrosis was observed in the newly developing leaves. The features of the observed resistance were analyzed and are consistent with two different mechanisms of resistance. In transgenic plants inoculated with CMV-FL strain, the symptomless phenotype was correlated to the down-regulation of CMV by Tfn-satRNA, amplified from the transgene transcripts, as the first resistance mechanism. On the other hand, the delayed resistance to CW-77 in transgenic tomato lines was mediated by a degradation process that targets satRNAs in a sequence-specific manner. Evidence is provided for a correlation between a reduced accumulation level of transgenic messenger Tfn-satRNA, the accumulation of small (approximately 23 nucleotides) RNAs with sequence homology to satRNAs, the progressively reduced accumulation of 77-satRNA in infected tissues, and the transition in infected plants from diseased to healthy. Thus, events leading to the degradation of satRNA sequences indicate a role for RNA silencing as the second mechanism determining resistance of transgenic tomato lines

An enzyme-linked immunosorbent assay for the detection of autoantibodies to albumin.

The development of an enzyme-linked immunosorbent assay (ELISA) for anti-albumin autoantibodies (AAA), using immobilized monomeric or glutaraldehyde-polymerized human, bovine or egg albumin, is described. Major problems in detection by the ELISA of AA against human albumin (HSA) were due to high 'non-specific' binding with the commercial anti-human immunoglobulin antisera used and to interference by IgM/HBs circulating complexes. However, it was found that AAA are not species-specific and that these problems may be overcome using immobilized bovine (BSA) or egg (EggA) albumin. AAA were found to have a similar affinity for BSA as for HSA but slightly lower for EggA, while AAA affinities for the monomeric forms were lower than for the corresponding polymeric albumins. All sera from the 28 normal subjects tested were found to contain both IgM- and IgG-AAA. Patients with acute hepatitis B (n = 23) had significantly lower titres of IgM-AAA than normal subjects, as did chronic HBV carriers with (n = 33) or without (= 17) underlying liver disease, while IgG-AAA titres were reduced only in the acute hepatitis patients. These findings support the concept that AAA have a normal physiological function (probably for removal of effete albumin molecules) and that, in HBV infection, there is a decrement in titres that may be related to the clearance of the virus

Correlation between hepatitis B virus deoxyribonucleic acid and receptors for polymerized human albumin in HBV chronic infection.

This study indicates that hepatitis B virus deoxyribonucleic acid (HBV DNA) is actually the most sensitive marker for the identification of HBV-related pathologies in active replication phase and does not correlate with serum receptor activity for polymerized human serum albumin which can be found in absence of either HBV DNA or HBeAg in HBV chronic infection

Autoantibody to albumin of type G and M in acute and chronic viral hepatitis.

Autoantibodies to albumin (AAA) were tested by an ELISA method in patients with A, B and NANB acute and chronic hepatitis, and in a control group. AAA-IgM had a different behaviour in acute hepatitis type A, in which we observed a high average titre as compared with B, and NANB hepatitis, in which we observed a decrease in the average titre. In the chronic phase, we noted a decrement of the average titre in all the types of hepatitis. For AAA-IgG, in the acute phase the average titre in hepatitis A, B and NANB was lower than in the control group. In the chronic stage, only NANB hepatitis showed a decrement of the average titre of the antibody. On the base of these results, we can say that the involvement of AAA seems to be different in hepatitis A from the other two types, in which the decrement of average titre may be explained by the formation of immunocomplexes which are not detected by this test

Demonstration of HBsAg as the antigen component in circulating immune complexes detected by peg-solid phase test.

The development of an enzyme-linked immunosorbent assay to identify HBsAg as the antigen component within circulating immune complexes using immobilized polyethylene glycol (PEG) is described. The method utilizes, on one hand, the ability of PEG to bind stably to plastic supports and, on the other, to precipitate circulating macromolecules. This method is easily performed, very cheap, quick and, above all, it helps define the biological nature of the immune complexes. HBsAg can be revealed as the antigen component of HBsAg/anti-HBs soluble immune complexes at concentrations of at least 20 ng/ml and either in antigen or antibody excess. Our results indicate that HBsAg circulates in a complexed form in 47% of HBsAg chronic carriers and in 10.7% of patients with liver disease who are positive for serum antibody to hepatitis B surface antigen (anti-HBs) and to core antigen (anti-HBc). None of the other groups of patients in the study had circulating HBsAg in the complexed form

Serum binding activity for human albumin polymers in acute and chronic virus hepatitis.

We considered the serum binding activity for human albumin polymerized with glutaraldehyde in 346 serum samples of 205 subjects with acute and chronic type A, B and non-A, non-B virus hepatitis. We showed that the binding activity for pHSA in the control groups did not have a titer higher than 2(-6). All sera from patients with HAV and HBV acute infection showed a high binding titer that returned to below the threshold in the former after the peak of hepatocytolysis, and in the latter after the seroconversion of HBsAg to anti-HBs. In the subjects who became HBsAg chronic carriers after the acute episode of HBV infection, the pHSA binding activity showed a decrement of the titer in relation to the seroconversion of HBeAg to anti-HBe. Furthermore, 92% of HBsAg chronic carriers who were HBeAg positive had a high titer of pHSA binding, while only 14.3% of the anti-HBe positives showed a high titer. Acute and chronic hepatitis non-A, non-B virus showed a pHSA binding titer similar to that of the control group. The results indicate that the non-A, non-B virus does not seem to be correlated to pHSA or related factors