Weak anti-HIV CD8(+) T-cell effector activity in HIV primary infection

Area of Science:

• Immunology
• Virology
• Infectious Diseases

Background:

• HIV-specific CD8(+) T cells are crucial for controlling viral replication during primary infection (PI).
• However, these T cells do not completely prevent viral spread in early-stage Human Immunodeficiency Virus (HIV) infection.

Purpose of the Study:

• To characterize the ex vivo CD8(+) T-cell responses to various HIV epitopic peptides in individuals with early HIV PI.
• To compare the breadth and characteristics of T-cell responses between primary and chronic HIV infection stages.

Main Methods:

• Utilized IFN-gamma enzyme-linked immunospot assay and intracellular staining to analyze CD8(+) T-cell responses.
• Assessed responses to a wide array of HIV epitopic peptides in 24 subjects with early HIV PI and 30 asymptomatic chronic HIV subjects.

Main Results:

• HIV-specific T-cell responses were detected in 71% of subjects during PI, recognizing a median of 2 peptides (Gag and Nef frequently recognized).
• In contrast, chronic infection showed broader responses (median 13 peptides) in all subjects.
• The proportion of terminally differentiated CD8(+)CD28(-) T cells was lower in PI compared to chronic infection.

Conclusions:

• The limited immune response during HIV PI may contribute to the failure to control viral replication.
• Findings highlight the importance of early immune status for HIV control and inform strategies for immunotherapies and vaccine development.