The surface antigens of orthopoxviruses detected by cross-neutralization tests on cross-absorbed antisera

Area of Science:

• Virology
• Immunology
• Molecular Biology

Background:

• The genus Orthopoxvirus includes significant human and animal pathogens.
• Accurate identification and differentiation of Orthopoxvirus strains are crucial for public health and vaccine development.
• Understanding viral antigenicity is key to developing effective diagnostic and prophylactic measures.

Purpose of the Study:

• To characterize the antigenic relationships among various Orthopoxvirus species and isolates.
• To identify and map the distribution of neutralizing antigens within the Orthopoxvirus genus.
• To assess the utility of cross-neutralization tests for Orthopoxvirus identification.

Main Methods:

• Cross-neutralization assays were performed using antisera absorbed with different Orthopoxvirus strains.
• The distribution of four distinct neutralizing antigens was determined across 13 Orthopoxvirus strains.
• Specific Orthopoxvirus strains were analyzed for unique antigenic profiles.

Main Results:

• Four neutralizing antigens were identified, with distinct distributions among strains like monkeypox, camelpox, and ectromelia.
• Certain Orthopoxvirus vaccines (Lister, Wyeth, Copenhagen, EM63) showed unique antigenic profiles.
• Cowpox, buffalopox, MK 10, and Moscow poxviruses were antigenically indistinguishable.
• Shared surface antigens between viruses sometimes hindered complete neutralization, reducing diagnostic value.
• A fifth antigen was found to potentially interfere with neutralization by blocking antibodies.

Conclusions:

• Cross-neutralization tests can delineate antigenic differences and similarities within the Orthopoxvirus genus.
• The presence of shared and interfering antigens complicates precise viral identification using neutralization assays alone.
• Further research into Orthopoxvirus antigen structure and function is warranted for improved diagnostics and vaccines.