What is the Difference Between HBeAg and HBcAg

The key difference between HBeAg and HBcAg is that HBeAg is a hepatitis B viral antigen that circulates in the blood of the infected person, while HBcAg is a hepatitis B viral antigen that does not circulate in the blood of the infected person.

Hepatitis B is a liver infection caused by the hepatitis B virus. This infection transmits through the blood, semen, or other body fluid of an infected person. The infected person has symptoms such as vomiting, yellowish skin, tiredness, and abdominal pain. Normally, this infection can be prevented by a vaccine. Hepatitis B virus is a member of the hepadnavirus family. This virus has different important antigens: HBsAg, HBeAg and HBcAg, which help the viral infection. Therefore, HBeAg and HBcAg are two distinct hepatitis B viral antigens.

CONTENTS

1. Overview and Key Difference
2. What is HBeAg  
3. What is HBcAg
4. Similarities – HBeAg and HBcAg
5. HBeAg vs HBcAg in Tabular Form
6. Summary – HBeAg vs HBcAg

What is HBeAg?

HBeAg is a hepatitis B viral antigen (protein) that circulates in the blood of an infected person. It is usually an active indicator of viral replication. HBeAg indicates that a person is infectious, meaning that he is able to transmit the disease to another person. This antigen can be found between an icosahedral nucleocapsid core and a lipid envelope. The nucleocapsid core is the innermost layer, and the lipid envelope is the outermost layer of the hepatitis B virus. HBeAg antigen is considered non-particulate or secretory. This is because HBeAg is secreted and is accumulated in the serum of the infected person as an immunologically distinct antigen.

HBeAg and HBcAg antigens are made from the same open reading frame. This is the reason why both these proteins together act as a marker of viral replication. The antibodies for these antigens are a marker of declining viral replication. Moreover, the presence of this antigen in the infected person’s serum can serve as a marker of active replication in chronic hepatitis. The function of this antigen is not well understood yet. However, one research work detected that it can down-regulate Toll-like receptor 2 expression on hepatocytes and monocytes, which leads to a decrease in cytokine expression.

What is HBcAg?

HBcAg is a hepatitis B viral antigen (protein) that does not circulate in the blood of the infected person. It is also called the hepatitis B core antigen. It also acts as an active indicator of viral replication. This antigen can be found on the surface of the nucleocapsid core. Both HBcAg and HBeAg are made from the same open reading frame. However, it is considered particulate or non-secretory.

Although HBcAg does not circulate in the blood, it is readily detected in hepatocytes after a biopsy. The presence of both HBcAg and HBeAg antigens together indicates viral replication. On the other hand, their antibodies are a marker of declining viral replication. Furthermore, tapasin is a glycoprotein that interacts HBcAg and enhances cytotoxic T– lymphocyte response against HBV.

What are the Similarities Between HBeAg and HBcAg?

• HBeAg and HBcAg are two distinct hepatitis B viral antigens.
• Both are produced by the same open reading frame (ORF).
• They are proteins.
• Both antigens share constituent amino acids.
• Together, they act as a marker of viral replication.

What is the Difference Between HBeAg and HBcAg?

HBeAg is a hepatitis B viral antigen that circulates in the blood of an infected person, while HBcAg is a hepatitis B viral antigen that does not circulate in the blood of an infected person. So, this is the key difference between HBeAg and HBcAg. Furthermore, HBeAg is located between the icosahedral nucleocapsid core and the lipid envelope. On the other hand, HBcAg is located on the surface of the nucleocapsid core.

The below infographic lists the differences between HBeAg and HBcAg in tabular form for side by side comparison.

Summary – HBeAg vs HBcAg

Hepatitis infection is a vaccine-preventable liver disease caused by the hepatitis B virus. HBeAg and HBcAg are two distinct hepatitis B viral antigens. HBeAg viral antigen circulates in the blood of the infected person while HBcAg viral antigen does not circulate in the blood of the infected person. Thus, this is the key difference between HBeAg and HBcAg.

Reference:

1. “Hepatitis B(E) Antigen.” An Overview | ScienceDirect Topics.
2. “HBCAG.” An Overview | ScienceDirect Topics.

Image Courtesy:

1. “HBV serum markers” (CC BY 3.0) via Commons Wikimeida
2. “Hepatitis B virus phases of chronic infection” By Gwilz – Own work (CC BY-SA 4.0) via Commons Wikimedia