IgA immunity in HIV type 1-infected chimpanzees. I. Systemic immunity

Area of Science:

• Immunology
• Virology
• Primatology

Background:

• Human immunodeficiency virus (HIV) infection disrupts cellular and humoral immunity, notably affecting B lymphocyte function and immunoglobulin A (IgA) regulation in humans.
• Elevated serum IgA concentrations are a common observation in HIV-infected individuals, indicating immune system dysregulation.

Purpose of the Study:

• To investigate whether HIV-1 infection induces similar IgA abnormalities in chimpanzees as observed in humans.
• To analyze changes in total IgA, IgG, and IgM levels and specific antibody responses to HIV antigens in infected chimpanzees.

Main Methods:

• Longitudinal serum sampling from six HIV-1-infected chimpanzees and one control.
• Quantification of total IgA, IgG, and IgM levels.
• ELISA for IgA subclasses, enzyme immunoassay (EIA), and Western blot analysis for HIV-specific antibodies (IgG, IgA, IgA1, IgA2), including analysis of IgG-depleted sera.

Main Results:

• Two infected chimpanzees showed increased serum immunoglobulins, while two others exhibited a transient decrease in IgA, IgG, and IgM.
• Two chimpanzees displayed stable immunoglobulin levels throughout the study period.
• Abnormalities in the IgA2 subclass were noted in animals without significant overall immunoglobulin fluctuations; IgA reactivity against HIV antigens was sometimes enhanced after IgG depletion.

Conclusions:

• HIV-1 infection can induce serum IgA abnormalities in chimpanzees, mirroring some human responses.
• Findings contribute to understanding HIV-induced humoral immune responses and may inform research on HIV in humans.