Tick histamine-binding proteins and related lipocalins: potential as therapeutic agents.

Tick histamine-binding proteins bind histamine with high affinity and specificity. This is attained by a novel binding mechanism, whereby histamine is sequestered within a binding cavity of the lipocalin fold. The histamine binding proteins and related protein family members are currently under investigation as potential therapeutic agents for the treatment of various diseases, including conjunctivitis, allergic rhinitis, carcinoid syndrome and rheumatoid arthritis. While these proteins show great therapeutic potential, they are part of a diverse family of tick lipocalin proteins, some of which have been implicated in tick-host rejection and host pathogenesis. As such, the therapeutic mining of tick lipocalins should be considered within the framework of the rest of the family.