Separate Ia-like determinants in human lymphocytes and macrophages

Area of Science:

• Immunology
• Cell Biology
• Transplantation Science

Background:

• Human alloantisera are crucial tools for identifying cell surface antigens.
• Monocytes and B-lymphocytes share some cell surface markers, complicating specific antibody identification.
• Macrophages play significant roles in immune responses and transplantation.

Purpose of the Study:

• To investigate the presence and specificity of antibodies reacting with human macrophages.
• To determine if macrophage-specific alloantigens exist and are distinct from B-lymphocyte antigens.
• To explore the potential link between macrophage alloantigens and histocompatibility functions.

Main Methods:

• Utilizing carbonyl iron treatment to deplete monocytes from B-lymphocyte preparations.
• Testing alloantisera reactivity against both depleted B-lymphocyte preparations and isolated monocyte populations.
• Performing absorption experiments using B-lymphocyte and monocyte preparations.
• Analyzing sera from multiparous women and kidney transplant recipients for macrophage antibodies.

Main Results:

• Alloantisera cytotoxic for B-lymphocytes lost reactivity after monocyte depletion, indicating reactivity with monocytes.
• These sera reacted specifically with isolated monocyte preparations.
• Macrophage antibodies were detected in 38% of sera from multiparous women and 70% from kidney transplant recipients.
• Absorption with B-lymphocytes did not remove reactivity with macrophages, confirming distinct determinants.

Conclusions:

• Human macrophages express alloantigens distinct from those on B-lymphocytes.
• Macrophage alloantigens are present in a significant proportion of the general population and transplant recipients.
• These macrophage alloantigens may be products of genes associated with histocompatibility and immune functions.