Tissue-specific B-cell dysfunction and generalized memory B-cell loss during acute SIV infection

Area of Science:

• Immunology
• Virology
• Cell Biology

Background:

• Primary HIV infection causes irreversible B-cell damage, not fully restored by HAART.
• Studying simian immunodeficiency virus (SIV) in macaques offers insights into B-cell dysfunction during acute infection.
• Lymphoid organ accessibility limits longitudinal studies in primary HIV infection.

Purpose of the Study:

• To investigate tissue-specific B-cell dysfunctions in acutely SIV-infected Cynomolgus macaques.
• To compare B-cell phenotypes, functions, and lymphoid tissue organization during SIV infection and HAART treatment.
• To elucidate the impact of SIV infection and HAART on B-cell trafficking and memory B-cell loss.

Main Methods:

• Infection of macaques with SIV mac251 at different time points (14, 21, 28 days post-infection).
• Treatment with HAART initiated at various early time points post-infection (4h, 7 days, 14 days).
• Simultaneous assessment of B-cell phenotypes, functions, and lymphoid organ architecture.

Main Results:

• SIV infection led to a steady decline in memory B-cells (SIgD(-)CD27(+)) in spleen and lymph nodes.
• B-cells selectively homed to or sequestered in the small intestine and spleen during SIV infection.
• HAART reduced B-cell apoptosis and SIV-specific antibody production but did not prevent memory B-cell loss or splenic B-cell increase.

Conclusions:

• SIV infection causes tissue-specific B-cell trafficking and functional impairments, along with generalized memory B-cell loss.
• Early B-cell dysfunction is influenced by virus-B-cell interactions and inflammatory cytokines.
• Further research into underlying mechanisms can guide therapeutic strategies to enhance HIV/SIV-specific antibody responses.