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Peptidomics and genomics analyses were used to study an anti-infection array of peptides of amphibian skin. 372 cDNA sequences of antimicrobial peptides were characterized from a single individual skin of the frog Odorrana grahami that encode 107 novel antimicrobial peptides. This contribution almost triples the number of currently reported amphibian antimicrobial peptides. The peptides could be organized into 30 divergent groups, including 24 novel groups. The diversity in peptide coding cDNA sequences is, to our knowledge, the most extreme yet described for any animal. The patterns of diversification suggest that point mutations as well as insertion, deletion, and "shuffling" of oligonucleotide sequences were responsible for the diversity. The diversity of antimicrobial peptides may have resulted from the diversity of microorganisms. These diverse peptides exhibited both diverse secondary structure and "host defense" properties.

LJM11, an abundant salivary protein from the sand fly Lutzomyia longipalpis, belongs to the insect "yellow" family of proteins. In this study, we immunized mice with 17 plasmids encoding L. longiplapis salivary proteins and demonstrated that LJM11 confers protective immunity against Leishmania major infection. This protection correlates with a strong induction of a delayed type hypersensitivity (DTH) response following exposure to L. longipalpis saliva. Additionally, splenocytes of exposed mice produce IFN-␥ upon stimulation with LJM11, demonstrating the systemic induction of Th1 immunity by this protein. In contrast to LJM11, LJM111, another yellow protein from L. longipalpis saliva, does not produce a DTH response in these mice, suggesting that structural or functional features specific to LJM11 are important for the induction of a robust DTH response. To examine these features, we used calorimetric analysis to probe a possible ligand binding function for the salivary yellow proteins. LJM11, LJM111, and LJM17 all acted as high affinity binders of prohemostatic and proinflammatory biogenic amines, particularly serotonin, catecholamines, and histamine. We also determined the crystal structure of LJM11, revealing a six-bladed ␤-propeller fold with a single ligand binding pocket located in the central part of the propeller structure on one face of the molecule. A hypothetical model of LJM11 suggests a positive electrostatic potential on the face containing entry to the ligand binding pocket, whereas LJM111 is negative to neutral over its entire surface. This may be the reason for differences in antigenicity between the two proteins.The salivary secretions of blood-feeding insects contain a rich mixture of proteins that act to prevent host hemostatic and inflammatory responses (1, 2). Individual proteins in the saliva inhibit the essential processes of coagulation, platelet activation, vasoconstriction, inflammation, and mast cell function (2). Additionally, certain of these salivary proteins are immunogenic, conferring protection against cutaneous and visceral leishmaniasis in several animal models following exposure to sand fly bites or immunization with a salivary component (3-9). In most of these studies, protection correlates with a delayed type hypersensitivity (DTH) 3 response to saliva or to a protective salivary molecule in the host skin that alters the outcome of infection (10, 11). These studies have established the potential of salivary proteins as components of vaccines against leishmaniasis.A major protein family in the saliva of the sand fly genera Lutzomyia and Phlebotomus is related by sequence to the "yellow" protein of Drosophila melanogaster and the major royal jelly proteins (MRJPs) of bees. Immunization with LJM11, a yellow protein from saliva of Lutzomyia longipalpis, protects hamsters against visceral leishmaniasis up to 2 months postinfection (4). This partial protection was associated with the induction at the site of challenge of a DTH response composed mainly of a mononuclear infiltrate ...