Final answer:
The presence of Hepatitis B surface antigen (HBsAg) and antibodies indicates different stages of Hepatitis B infection. In acute and chronic stages, HBsAg is present, while during recovery and after vaccination, the antigen is absent but specific antibodies to HBsAg exist. The Hepatitis B vaccine elicits an immune response using recombinant DNA technology to produce HBsAg in yeast cells without causing the disease.
Step-by-step explanation:
The presence and absence of Hepatitis B surface antigen (HBsAg) and antibodies (Abs) can indicate various stages of Hepatitis B infection, including acute infection, chronic infection, recovery, and immunity through vaccination. During an acute infection, HBsAg is typically present as it indicates a current infection. Conversely, in a chronic infection, HBsAg remains positive beyond six months, suggesting the virus continues to replicate and the infection has not resolved.
In the recovery phase, HBsAg will no longer be detected, and antibodies specific to HBsAg (anti-HBs) will be present, indicating the body has cleared the infection and developed immunity. After receiving the Hepatitis B vaccine, which is produced via recombinant DNA technology using yeast cells, only anti-HBs antibodies are present. This reflects the body’s immune response to the vaccine without any ongoing or previous infection.
Regarding other vaccines, they work on a similar principle where components like the capsid protein VP3 for hepatitis A, pneumococcal capsular polysaccharide for pneumonia, and haemagglutinin and neuraminidase for influenza are used to elicit an immune response without causing the disease. Specific treatments for chronic Hepatitis B include the use of interferon alpha 2b and antiviral medications like lamivudine, entecavir, adefovir, and telbivudine.