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Effect of tear secretory IgA on chemotaxis of polymorphonuclear leucocytes
J X Lan1, M D Willcox, G D Jackson
1Cooperative Research Centre for Eye Research and Technology, School of Microbiology and Immunology, University of New South Wales, Sydney, Australia. jenny@cclru.unsw.edu.au
Purpose:
The aim of the present study was to examine the effect of tear and purified colostrum secretory IgA (sIgA) on polymorphonuclear leucocyte (PMN) chemotaxis.
Methods:
The chemotactic effect of tear and purified sIgA for PMN was studied using a modified Boyden chamber. Tears treated with anti-human IgA, complement-inactivated tears and albumin were used as controls.
Results:
The data indicate that both tear and purified sIgA are highly chemotactic for PMN. Anti-sIgA antibodies reduced the chemotactic effect of closed-eye tears (34%) and tear collected during ocular inflammation.
Conclusion:
The massive recruitment of PMN in tears during sleep may be partially attributed to the increased levels of tear sIgA. This may play an important role in protecting the eye against bacterial infection.
Insights
Tear secretory IgA (sIgA) and purified sIgA attract polymorphonuclear leucocytes (PMNs), indicating a role in ocular defense. Increased tear sIgA may contribute to PMN recruitment during sleep, aiding protection against bacterial eye infections.
Area of Science:
- Immunology
- Ophthalmology
- Cell Biology
Background:
- Secretory IgA (sIgA) is a critical component of mucosal immunity.
- Tears contain various immune factors, including sIgA, which plays a role in ocular surface protection.
Purpose of the Study:
- To investigate the chemotactic effect of tear and purified colostrum secretory IgA (sIgA) on polymorphonuclear leucocytes (PMNs).
Main Methods:
- Modified Boyden chamber assay was used to assess PMN chemotaxis.
- Tears treated with anti-human IgA, complement-inactivated tears, and albumin served as controls.
Main Results:
- Both tear and purified sIgA demonstrated significant chemotactic activity for PMNs.
- Anti-sIgA antibodies diminished the chemotactic response of tears from closed eyes and during ocular inflammation by 34%.
Conclusions:
- Elevated tear sIgA levels may partially explain the substantial recruitment of PMNs in tears during sleep.
- Tear sIgA likely plays a crucial role in the eye's defense against bacterial infections.