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Virus-like antigen associated with hepatitis A: investigations in children's acute hepatitis
Abstract:
Stool specimens, collected from 8 children with viral hepatitis [5 of type A, presumably, and 3 of type B (HBsAg-positive)] during the acute phase, were examined in the electron microscope. The presence of 27-nm virus-like particles, aggregated by the convalescent serum of a chimpanzee infected with MS-1 and not by the serum of the same animal drawn before infection, was detected by immune electron microscopy (IEM) in the stools of 3 out of the 5 children with suspected hepatitis A. The virus-like particles (HA-Ag) present in the stools were aggregated by the serum drawn from the corresponding subject during convalescence and not by that obtained in the acute phase of the disease. Employing as antigen a stool particle preparation purified by isopycnic banding in cesium cloride, it was pointed out that, in all 5 children with suspected hepatitis A, antibodies capable to cause the aggregation of HA-Ag particles, appeared. Anti-HA antibodies turned out to be present also in three lots of commercial immunoglobulins. In the three subjects with type B hepatitis (HBsAg-positive) neither virus-like particles with a 27-nm diameter were observed, nor anti-HA antibodies appeared in the convalescent serum.
Insights
Researchers identified 27-nm virus-like particles in children with suspected hepatitis A. These particles, termed HA-Ag, were aggregated by convalescent serum, indicating a link to hepatitis A virus (HAV) infection.
Area of Science:
- Hepatology
- Virology
- Immunology
Background:
- Viral hepatitis remains a significant global health concern, particularly in children.
- Distinguishing between different types of viral hepatitis, such as hepatitis A and B, is crucial for effective management and treatment.
- The causative agents of some forms of viral hepatitis, especially non-A, non-B types, have been challenging to identify.
Purpose of the Study:
- To investigate the presence of virus-like particles in stool samples from children with viral hepatitis.
- To characterize these particles using immune electron microscopy (IEM) and serological assays.
- To determine if these particles are associated with hepatitis A virus (HAV) infection.
Main Methods:
- Stool specimens were collected from children during the acute phase of viral hepatitis.
- Immune electron microscopy (IEM) was used to examine virus-like particles.
- Agglutination assays were performed using chimpanzee and patient sera.
- Purified virus-like particles were used as antigen to detect specific antibodies.
Main Results:
- 27-nm virus-like particles, designated HA-Ag, were detected in stools of 3 out of 5 children with suspected hepatitis A.
- These HA-Ag particles were aggregated by convalescent chimpanzee serum and patient convalescent sera, but not by acute-phase sera.
- Antibodies against HA-Ag were detected in all 5 children with suspected hepatitis A and in commercial immunoglobulins.
- No such particles or antibodies were found in children with hepatitis B (HBsAg-positive).
Conclusions:
- The identified 27-nm virus-like particles (HA-Ag) are likely associated with hepatitis A virus (HAV).
- The presence of anti-HA antibodies in convalescent sera and commercial immunoglobulins supports this association.
- These findings contribute to the understanding and diagnosis of hepatitis A in children.