Phage display identifies two Caprine Arthritis Encephalitis Virus env epitopes

Area of Science:

• Virology
• Immunology
• Molecular Biology

Background:

• Caprine Arthritis Encephalitis Virus (CAEV) is a significant pathogen affecting small ruminants.
• Understanding the virus's surface proteins and their immunogenic sites is crucial for developing control strategies.
• The Env protein of CAEV plays a vital role in viral entry and is a primary target for the host immune response.

Purpose of the Study:

• To identify and characterize immunogenic epitopes on the CAEV Env protein using phage display technology.
• To map these epitopes to specific regions of the mature gp135 amino acid sequence.
• To assess the conservation of these epitopes across different CAEV isolates and related viruses.

Main Methods:

• Phage display technology was employed using IgG from a goat infected with CAEV.
• Families of 7-mer constrained peptides were generated and analyzed for consensus motifs (LxSDPF/Y and SWN/KHWSY).
• Epitope mapping was performed on the Env gp135 amino acid sequence at specific sites (Env 6-LISDPY-11 and 67-WNTYHW-72).

Main Results:

• Two distinct epitopes were identified: one at the N-terminal immunogenic site (aa1-EDYTLISDPYGFS-aa14) and a newly described one (aa67-WNTYHW-72).
• The first epitope is largely conserved across CAEV isolates.
• The second, newly identified epitope, demonstrates extreme conservation within Small Ruminant Lentiviruses env sequences.

Conclusions:

• The identified epitopes are immunodominant and represent potential targets for diagnostic applications.
• These epitopes are promising candidates for the development of mimotope-mediated neutralization strategies against CAEV.
• The high conservation of the second epitope suggests its importance in viral pathogenesis and potential as a universal target for small ruminant lentiviruses.