ABSTRACT
FREP Induction ................................................................................................... 484 32.5 Surprising Extent of FREP Diversity ............................................................................... 484 32.5.1 Biological Signi cance of FREP Diversi cation ................................................ 485 32.6 Some Remaining Puzzles and Some Speculations ........................................................... 486 32.7 Conclusion and Future Directions ..................................................................................... 487 Acknowledgments ........................................................................................................................ 487 References .................................................................................................................................... 488
The concept that invertebrates employ lectins to mediate nonself recognition in an immune context, proposed decades ago [1,2], holds true to date. Extensive experimental data in the literature and in sequence databases con rm that both invertebrate and vertebrate organisms use lectins as pattern recognition molecules (PRMs) to detect pathogen-associated molecular patterns (PAMPs) and activate defense responses [3-6]. In the absence of lymphocyte-derived defense components (T-cells, B-cells, antibodies, and T-cell receptors) [7], invertebrates may rely extensively on lectin-mediated pattern recognition of pathogens for their defense.
