Ixodes dammini: salivary anaphylatoxin inactivating activity.

Area of Science:

• Parasitology
• Biochemistry
• Immunology

Background:

• Anaphylatoxins and bradykinin are potent mediators of inflammation.
• Tick saliva components can modulate host responses during blood feeding.

Purpose of the Study:

• To investigate the biochemical activity of Ixodes dammini tick saliva.
• To determine the effect of tick saliva on anaphylatoxin and bradykinin.

Main Methods:

• Testing tick saliva's effect on guinea pig ileum preparations stimulated with histamine.
• Assessing the impact of saliva on intradermal anaphylatoxin-induced edema in guinea pigs.
• Evaluating saliva's influence on polymorphonuclear leukocyte aggregation.
• Measuring the inactivation of various peptides including bradykinin, angiotensin I, angiotensin II, and substance P.

Main Results:

• Tick saliva abolished anaphylatoxin's effects on guinea pig ileum and local edema.
• Saliva did not affect anaphylatoxin-induced polymorphonuclear leukocyte aggregation.
• Bradykinin and lysil-bradykinin were inactivated by saliva.
• Angiotensin I, angiotensin II, and substance P remained unaffected.
• Amino acid release patterns suggested a carboxypeptidase with specificity for terminal basic amino acids.

Conclusions:

• Ixodes dammini saliva possesses a carboxypeptidase activity.
• This enzyme likely inactivates anaphylatoxin and bradykinin at the tick attachment site.
• This mechanism may contribute to successful tick feeding by modulating host inflammatory responses.