The antiperinuclear factor: II. A light microscopical and immunofluorescence study on the antigenic substrate

Area of Science:

• Cell Biology
• Immunology
• Histology

Background:

• The antiperinuclear factor (APF) is an autoantibody associated with certain autoimmune diseases.
• The precise antigenic target of APF within cells has not been fully elucidated.
• Understanding the cellular localization and nature of APF's target is crucial for diagnostic applications.

Purpose of the Study:

• To characterize the antigenic substrate of APF in human buccal mucosa cells.
• To evaluate alternative cellular substrates for APF detection.

Main Methods:

• Light microscopy and cytochemistry were employed to examine cellular morphology and staining properties.
• Immunofluorescence technique (IFT) was utilized to visualize APF binding.
• Autoantibodies and antisera against various tissue components were used for characterization.

Main Results:

• Cytoplasmic granules in buccal cells stained basophilic and were the target of APF.
• These granules did not react positively with stains for specific chemical components or lysosomal enzymes.
• Human vaginal epithelial cells and cryostat sections of human and rabbit buccal/oesophageal mucosa showed similar fluorescent granules when incubated with APF-positive sera.

Conclusions:

• The antigenic substrate of APF in human buccal cells comprises specific cytoplasmic granules.
• Rabbit buccal and oesophageal mucosa sections are unsuitable as diagnostic substrates due to decreased specificity and sensitivity.
• Further characterization of these granules is needed, but their presence in vaginal and buccal mucosa is confirmed.