Virus-specific cytotoxic T-lymphocyte responses select for amino-acid variation in simian immunodeficiency virus Env and Nef
Summary
This summary is machine-generated.Human immunodeficiency virus evades immune responses by altering cytotoxic T-lymphocyte (CTL) epitopes. This study shows viral mutations in CTL epitopes contribute to disease progression in macaques, supporting the CTL escape hypothesis.
Area Of Science
- Virology
- Immunology
- Genetics
Background
- Cytotoxic T-lymphocyte (CTL) responses are crucial in controlling human immunodeficiency virus (HIV) infection but often fail to prevent Acquired Immunodeficiency Syndrome (AIDS) progression.
- HIV evades CTL responses through accumulation of amino acid substitutions within CTL epitopes, a phenomenon known as viral escape.
Purpose Of The Study
- To investigate the role of CTL epitope evolution in simian immunodeficiency virus (SIV) disease progression in macaques.
- To determine if amino acid replacements in CTL epitopes correlate with immune evasion and disease outcome.
Main Methods
- Studied 10 specific CTL epitopes in three macaques throughout the course of SIV infection.
- Analyzed amino acid changes within these epitopes and assessed evidence of positive selection.
- Evaluated the impact of mutations on major histocompatibility complex (MHC) class I binding and CTL recognition.
Main Results
- All 10 studied CTL epitopes accumulated amino acid replacements by the time of macaque death.
- Evidence of positive selection was observed in all 10 epitopes, indicating viral adaptation.
- Many identified mutations reduced or abolished MHC class I binding and/or CTL recognition.
Conclusions
- Viral accumulation of amino acid replacements in CTL epitopes is a key mechanism of immune evasion during SIV infection.
- These escape mutations contribute to the failure of CTL responses to control viral replication and prevent disease progression.
- Findings strongly support the CTL escape hypothesis as a driver of lentiviral pathogenesis.
View abstract on PubMed