Amebiasis in Nicaragua: class specific serum antibody responses

Area of Science:

• Immunology
• Infectious Diseases
• Parasitology

Background:

• Entamoeba histolytica is a significant cause of parasitic infections.
• Understanding antibody responses is crucial for diagnosing and managing amoebiasis.

Purpose of the Study:

• To investigate the antibody profile against E. histolytica in León, Nicaragua.
• To compare antibody reactivity across different age groups and population types.

Main Methods:

• Indirect hemagglutination (IHA) test and IgG ELISA were used to analyze 562 sera.
• Treatment with 2-mercaptoethanol and immunofluorescence with anti-IgM conjugate were employed.
• Class-specific antibody reactivity was compared in healthy residents, cyst carriers, and patients with liver abscess.

Main Results:

• Highest seropositivity (48%) was observed in the 6-15 year age group.
• Discrepancies between IHA and IgG ELISA suggested reactivity in different immunoglobulin (Ig) classes.
• 2-mercaptoethanol reduced antibody titers in most tested sera, and IgM antibodies were detected in a subset of sera.
• No significant difference in antibody prevalence was found between healthy residents and cyst carriers.
• Cyst carriers showed IgA and/or IgM antibodies without detectable IgG.
• Patients with recent or acute liver abscess showed significantly high reactivity across all tests.

Conclusions:

• Antibody profiles against E. histolytica vary by age and clinical status.
• Different Ig classes play a role in the immune response to E. histolytica.
• The IHA test may involve non-specific reactions, necessitating careful interpretation alongside other diagnostic methods.